sharppy.sharptab package¶

Submodules¶

Modules that perform data analysis and processing tasks in SHARPpy.

sharppy.sharptab.constants module¶

Contains constants used by the SHARPpy routines.

Frequently used meteorological constants

sharppy.sharptab.fire module¶

Contains routines that analyze the potential for fire weather using sounding profiles.

sharppy.sharptab.fire.fosberg(prof)[source]¶

The Fosberg Fire Weather Index Adapted from code donated by Rich Thompson - NOAA Storm Prediction Center

Description: The FWI (Fire Weather Index) is defined by a quantitative model that provides a nonlinear filter of meteorological data which results in a linear relationship between the combined meteorological variables of relative humidity and wind speed, and the behavior of wildfires. Thus the index deals with only the weather conditions, not the fuels. Several sets of conditions have been defined by Fosberg (Fosberg, 1978) to apply this to fire weather management. The upper limits have been set to give an index value of 100 if the moisture content is zero and the wind is 30 mph.

Thus, the numbers range from 0 to 100 and if any number is larger than 100, it is set back to 100. The index can be used to measure changes in fire weather conditions. Over several years of use, Fosberg index values of 50 or greater generally appear significant on a national scale. The SPC fire weather verification scheme uses the Fosberg Index, but with a check for both temperature (60F) and adjective fire danger rating (3-High, 4-Very High, 5-Extreme).

Description Source - http://www.spc.noaa.gov/exper/firecomp/INFO/fosbinfo.html

WARNING: This function has not been fully tested.

Parameters: prof (profile object) – Profile object
Returns: param – Fosberg Fire Weather Index
Return type: number

sharppy.sharptab.fire.haines_height(prof)[source]¶

Haines Index Height calculation

Calculates the appropriate height category(Low/Mid/High) given the the lowest height in the sounding.

Adapted from S-591 course Added by Nickolai Reimer (NWS Billings, MT)

Parameters: prof (profile object) – Profile object
Returns: param – the Haines Index Height
Return type: number

sharppy.sharptab.fire.haines_high(prof)[source]¶

Haines Index High Elevation calculation

Calculates the Haines Index(Lower Atmosphere Severity Index) using the higher elevation parmeters, used above 3000ft or 914 m.

Pressure levels 700 mb and 500 mb Dewpoint depression at 700 mb

1 : < 18C 2 : 18C to 21C 3 : > 21C

1 : < 15C 2 : 15C to 20C 3 : > 20C

Adapted from S-591 course Added by Nickolai Reimer (NWS Billings, MT)

Parameters: prof (profile object) – Profile object
Returns: param – the Haines Index high
Return type: number

sharppy.sharptab.fire.haines_low(prof)[source]¶

Haines Index Low Elevation calculation

Calculates the Haines Index(Lower Atmosphere Severity Index) using the lower elevation parmeters, used below 1000ft or 305 m.

Pressure levels 950 mb and 850 mb Dewpoint depression at 850 mb

1 : < 4C 2 : 4C to 7C 3 : > 7C

1 : < 6C 2 : 6C to 9C 3 : > 9C

Adapted from S-591 course Added by Nickolai Reimer (NWS Billings, MT)

Parameters: prof (profile object) – Profile object
Returns: param – the Haines Index low
Return type: number

sharppy.sharptab.fire.haines_mid(prof)[source]¶

Haines Index Mid Elevation calculation

Calculates the Haines Index(Lower Atmosphere Severity Index) using the middle elevation parmeters, used between 1000 ft or 305 m and 3000 ft or 914 m.

Pressure levels 850 mb and 700 mb Dewpoint depression at 850 mb

1 : < 6C 2 : 6C to 10C 3 : > 10C

1 : < 6C 2 : 6C to 12C 3 : > 12C

Adapted from S-591 course Added by Nickolai Reimer (NWS Billings, MT)

Parameters: prof (profile object) – Profile object
Returns: param – the Haines Index mid
Return type: number

sharppy.sharptab.interp module¶

Contains routines that use the numpy interpolation routines to interpolate various variables in the sounding data.

Interpolation Routines

sharppy.sharptab.interp.pres(prof, h)[source]¶

Interpolates the given data to calculate a pressure at a given height

Parameters

prof (profile object) – Profile object
h (number, numpy array) – Height (m) of the level for which pressure is desired

Returns

Pressure (hPa) at the given height

Return type

number, numpy array

sharppy.sharptab.interp.hght(prof, p)[source]¶

Interpolates the given data to calculate a height at a given pressure

Parameters

prof (profile object) – Profile object
p (number, numpy array) – Pressure (hPa) of the level for which height is desired

Returns

Height (m) at the given pressure

Return type

number, numpy array

sharppy.sharptab.interp.temp(prof, p)[source]¶

Interpolates the given data to calculate a temperature at a given pressure

Parameters

prof (profile object) – Profile object
p (number, numpy array) – Pressure (hPa) of the level for which temperature is desired

Returns

Temperature (C) at the given pressure

Return type

number, numpy array

sharppy.sharptab.interp.dwpt(prof, p)[source]¶

Interpolates the given data to calculate a dew point temperature at a given pressure

Parameters

prof (profile object) – Profile object
p (number, numpy array) – Pressure (hPa) of the level for which dew point temperature is desired

Returns

Dew point tmperature (C) at the given pressure

Return type

number, numpy array

sharppy.sharptab.interp.vtmp(prof, p)[source]¶

Interpolates the given data to calculate a virtual temperature at a given pressure

Parameters

prof (profile object) – Profile object
p (number, numpy array) – Pressure (hPa) of the level for which virtual temperature is desired

Returns

Virtual tmperature (C) at the given pressure

Return type

number, numpy array

sharppy.sharptab.interp.components(prof, p)[source]¶

Interpolates the given data to calculate the U and V components at a given pressure

Parameters

prof (profile object) – Profile object
p (number, numpy array) – Pressure (hPa) of a level

Returns

U and V components at the given pressure (kts)

Return type

number, numpy array

sharppy.sharptab.interp.vec(prof, p)[source]¶

Interpolates the given data to calculate the wind direction and speed at a given pressure

Parameters

p (number, numpy array) – Pressure (hPa) of a level
prof (profile object) – Profile object

Returns

Wind direction (degrees) and magnitude (kts) at the given pressure

Return type

number, numpy array

sharppy.sharptab.interp.thetae(prof, p)[source]¶

Interpolates the given data to calculate theta-e at a given pressure

Parameters

prof (profile object) –
object (Profile) –
p (number, numpy array) –
(hPa) of the level for which temperature is desired (Pressure) –

Returns

Theta-E (C) at the given pressure

Return type

number, numpy array

sharppy.sharptab.interp.wetbulb(prof, p)[source]¶

Interpolates the given data to calculate a wetbulb temperature at a given pressure

Parameters

prof (profile object) –
object (Profile) –
p (number, numpy array) –
(hPa) of the level for which wetbulb temperature is desired (Pressure) –

Returns

Wetbulb temperature (C) at the given pressure

Return type

number, numpy array

sharppy.sharptab.interp.theta(prof, p)[source]¶

Interpolates the given data to calculate theta at a given pressure

Parameters

prof (profile object) –
object (Profile) –
p (number, numpy array) –
(hPa) of the level for which potential temperature is desired (Pressure) –

Returns

Theta (C) at the given pressure

Return type

number, numpy array

sharppy.sharptab.interp.mixratio(prof, p)[source]¶

Interpolates the given data to calculate water vapor mixing ratio at a given pressure

Parameters

prof (profile object) –
object (Profile) –
p (number, numpy array) –
(hPa) of the level for which mixing ratio is desired (Pressure) –

Returns

Water vapor mixing ratio (g/kg) at the given pressure

Return type

number, numpy array

sharppy.sharptab.interp.to_agl(prof, h)[source]¶

Convert a height from mean sea-level (MSL) to above ground-level (AGL)

Parameters

h (number, numpy array) – Height of a level
prof (profile object) – Profile object

Returns

Converted height (m AGL)

Return type

number, numpy array

sharppy.sharptab.interp.to_msl(prof, h)[source]¶

Convert a height from above ground-level (AGL) to mean sea-level (MSL)

Parameters

h (number, numpy array) – Height of a level
prof (profile object) – Profile object

Returns

Converted height (m MSL)

Return type

number, numpy array

sharppy.sharptab.params module¶

Contains a wide variety of routines that calculate convection indices.

Thermodynamic Parameter Routines

class sharppy.sharptab.params.DefineParcel(prof, flag, **kwargs)[source]¶

Bases: object

Create a parcel from a supplied profile object.

Parameters

prof (profile object) – Profile object
Keywords (Optional) – flag : int (default = 1) Parcel Selection
- Observed Surface Parcel (1) –
- Forecast Surface Parcel (2) –
- Most Unstable Parcel (3) –
- Mean Mixed Layer Parcel (4) –
- User Defined Parcel (5) –
- Mean Effective Layer Parcel (6) –
Keywords (Depending on Parcel Selected) (Optional) –
(flag) == 1 (Parcel) – None
(flag) == 2 (Parcel) –
pres (number (default = SFC - 100 hPa)) – Depth over which to mix the boundary layer; only changes temperature; does not affect moisture
(flag) == 3 (Parcel) –
pres – Depth over which to look for the the most unstable parcel
from the surface pressure (starting) – Parcel (flag) == 4: Mixed Layer Parcel
pres – Depth over which to mix the surface parcel
(flag) == 5 (Parcel) –
pres – Pressure of the parcel to lift
tmpc (number (default = Temperature at the provided pressure)) – Temperature of the parcel to lift
dwpc (number (default = Dew Point at the provided pressure)) – Dew Point of the parcel to lift
(flag) == 6 (Parcel) –
ecape (number (default = 100)) – The minimum amount of CAPE a parcel needs to be considered part of the inflow layer
ecinh (number (default = -250)) – The maximum amount of CINH allowed for a parcel to be considered as part of the inflow layer

class sharppy.sharptab.params.Parcel(**kwargs)[source]¶

Bases: object

Initialize the parcel variables

Parameters

pbot (number) – Lower-bound (pressure; hPa) that the parcel is lifted
ptop (number) – Upper-bound (pressure; hPa) that the parcel is lifted
pres (number) – Pressure of the parcel to lift (hPa)
tmpc (number) – Temperature of the parcel to lift (C)
dwpc (number) – Dew Point of the parcel to lift (C)

pres¶

parcel beginning pressure (mb)

Type: number

tmpc¶

parcel beginning temperature (C)

Type: number

dwpc¶

parcel beginning dewpoint (C)

Type: number

ptrace¶

parcel trace pressure (mb)

Type: array

ttrace¶

parcel trace temperature (C)

Type: array

blayer¶

Pressure of the bottom of the layer the parcel is lifted (mb)

Type: number

tlayer¶

Pressure of the top of the layer the parcel is lifted (mb)

Type: number

entrain¶

Parcel entrainment fraction (not yet implemented)

Type: number

lclpres¶

Parcel LCL (lifted condensation level) pressure (mb)

Type: number

lclhght¶

Parcel LCL height (m AGL)

Type: number

lfcpres¶

Parcel LFC (level of free convection) pressure (mb)

Type: number

lfchght¶

Parcel LCL height (m AGL)

Type: number

elpres¶

Parcel EL (equilibrium level) pressure (mb)

Type: number

elhght¶

Parcel EL height (m AGL)

Type: number

mplpres¶

Maximum Parcel Level (mb)

Type: number

mplhght¶

Maximum Parcel Level (m AGL)

Type: number

bplus¶

Parcel CAPE (J/kg)

Type: number

bminus¶

Parcel CIN below 500 mb (J/kg)

Type: number

bfzl¶

Parcel CAPE up to freezing level (J/kg)

Type: number

b3km¶

Parcel CAPE up to 3 km (J/kg)

Type: number

b6km¶

Parcel CAPE up to 6 km (J/kg)

Type: number

p0c¶

Pressure value at 0 C (mb)

Type: number

pm10c¶

Pressure value at -10 C (mb)

Type: number

pm20c¶

Pressure value at -20 C (mb)

Type: number

pm30c¶

Pressure value at -30 C (mb)

Type: number

hght0c¶

Height value at 0 C (m AGL)

Type: number

hghtm10c¶

Height value at -10 C (m AGL)

Type: number

hghtm20c¶

Height value at -20 C (m AGL)

Type: number

hghtm30c¶

Height value at -30 C (m AGL)

Type: number

wm10c¶

Wetbulb at -10 C (C)

Type: number

wm20c¶

Wetbulb at -20 C (C)

Type: number

wm30c¶

Wetbulb at -30 C (C)

Type: number

li5¶

500-mb lifted index (C)

Type: number

li3¶

300-mb lifted index (C)

Type: number

brnshear¶

Bulk Richardson Number Shear (kts)

Type: number

brnu¶

U-component Bulk Richardson Number Shear (kts)

Type: number

brnv¶

V-component Bulk Richardson Number Shear (kts)

Type: number

brn¶

Bulk Richardson Number (unitless)

Type: number

limax¶

Maximum lifted index value (C)

Type: number

limaxpres¶

Pressure at Maximum lifted index (mb)

Type: number

cap¶

Cap strength (C)

Type: number

cappres¶

Cap strength pressure (mb)

Type: number

bmin¶

Buoyancy minimum (C)

Type: number

bminpres¶

Pressure at the buoyancy minimum (mb)

Type: number

sharppy.sharptab.params.k_index(prof)[source]¶

Calculates the K-Index from a profile object

Parameters: prof (profile object) – Profile Object
Returns: k_index – K-Index
Return type: number

sharppy.sharptab.params.t_totals(prof)[source]¶

Calculates the Total Totals Index from a profile object

Parameters: prof (profile object) – Profile Object
Returns: t_totals – Total Totals Index
Return type: number

sharppy.sharptab.params.c_totals(prof)[source]¶

Calculates the Cross Totals Index from a profile object

Parameters: prof (profile object) – Profile Object
Returns: c_totals – Cross Totals Index
Return type: number

sharppy.sharptab.params.v_totals(prof)[source]¶

Calculates the Vertical Totals Index from a profile object

Parameters: prof (profile object) – Profile Object
Returns: v_totals – Vertical Totals Index
Return type: number

sharppy.sharptab.params.precip_water(prof, pbot=None, ptop=400, dp=- 1, exact=False)[source]¶

Calculates the precipitable water from a profile object within the specified layer. The default layer (lower=-1 & upper=-1) is defined to be surface to 400 hPa.

Parameters

prof (profile object) – Profile Object
pbot (number (optional; default surface)) – Pressure of the bottom level (hPa)
ptop (number (optional; default 400 hPa)) – Pressure of the top level (hPa).
dp (negative integer (optional; default = -1)) – The pressure increment for the interpolated sounding
exact (bool (optional; default = False)) – Switch to choose between using the exact data (slower) or using interpolated sounding at ‘dp’ pressure levels (faster)

Returns

pwat – Precipitable Water (in)

Return type

number,

sharppy.sharptab.params.temp_lvl(prof, temp, wetbulb=False)[source]¶

Calculates the level (hPa) of the first occurrence of the specified temperature.

Parameters

prof (profile object) – Profile Object
temp (number) – Temperature being searched (C)
wetbulb (boolean) – Flag to indicate whether or not the wetbulb profile should be used instead

Returns

First Level of the temperature (hPa)

Return type

number

sharppy.sharptab.params.max_temp(prof, mixlayer=100)[source]¶

Calculates a maximum temperature forecast based on the depth of the mixing layer and low-level temperatures

Parameters

prof (profile object) – Profile Object
mixlayer (number (optional; default = 100)) – Top of layer over which to “mix” (hPa)

Returns

mtemp – Forecast Maximum Temperature

Return type

number

sharppy.sharptab.params.mean_mixratio(prof, pbot=None, ptop=None, dp=- 1, exact=False)[source]¶

Calculates the mean mixing ratio from a profile object within the specified layer.

Parameters

prof (profile object) – Profile Object
pbot (number (optional; default surface)) – Pressure of the bottom level (hPa)
ptop (number (optional; default 400 hPa)) – Pressure of the top level (hPa)
dp (negative integer (optional; default = -1)) – The pressure increment for the interpolated sounding (mb)
exact (bool (optional; default = False)) – Switch to choose between using the exact data (slower) or using interpolated sounding at ‘dp’ pressure levels (faster)

Returns

Mean Mixing Ratio

Return type

number

sharppy.sharptab.params.mean_theta(prof, pbot=None, ptop=None, dp=- 1, exact=False)[source]¶

Calculates the mean theta from a profile object within the specified layer.

Parameters

prof (profile object) – Profile Object
pbot (number (optional; default surface)) – Pressure of the bottom level (hPa)
ptop (number (optional; default 400 hPa)) – Pressure of the top level (hPa)
dp (negative integer (optional; default = -1)) – The pressure increment for the interpolated sounding (mb)
exact (bool (optional; default = False)) – Switch to choose between using the exact data (slower) or using interpolated sounding at ‘dp’ pressure levels (faster)

Returns

Mean Theta

Return type

number

sharppy.sharptab.params.mean_thetae(prof, pbot=None, ptop=None, dp=- 1, exact=False)[source]¶

Calculates the mean theta-e from a profile object within the specified layer.

Parameters

prof (profile object) – Profile Object
pbot (number (optional; default surface)) – Pressure of the bottom level (hPa)
ptop (number (optional; default 400 hPa)) – Pressure of the top level (hPa)
dp (negative integer (optional; default = -1)) – The pressure increment for the interpolated sounding (mb)
exact (bool (optional; default = False)) – Switch to choose between using the exact data (slower) or using interpolated sounding at ‘dp’ pressure levels (faster)

Returns

Mean Theta-E

Return type

number

sharppy.sharptab.params.mean_relh(prof, pbot=None, ptop=None, dp=- 1, exact=False)[source]¶

Calculates the mean relative humidity from a profile object within the specified layer.

Parameters

prof (profile object) – Profile Object
pbot (number (optional; default surface)) – Pressure of the bottom level (hPa)
ptop (number (optional; default 400 hPa)) – Pressure of the top level (hPa)
dp (negative integer (optional; default = -1)) – The pressure increment for the interpolated sounding (mb)
exact (bool (optional; default = False)) – Switch to choose between using the exact data (slower) or using interpolated sounding at ‘dp’ pressure levels (faster)

Returns

Mean Relative Humidity

Return type

number

sharppy.sharptab.params.lapse_rate(prof, lower, upper, pres=True)[source]¶

Calculates the lapse rate (C/km) from a profile object

Parameters

prof (profile object) – Profile Object
lower (number) – Lower Bound of lapse rate (mb or m AGL)
upper (number) – Upper Bound of lapse rate (mb or m AGL)
pres (bool (optional; default = True)) – Flag to determine if lower/upper are pressure [True] or height [False]

Returns

lapse rate (C/km)

Return type

number

sharppy.sharptab.params.max_lapse_rate(prof, lower=2000, upper=6000, interval=250, depth=2000)[source]¶

Calculates the maximum lapse rate (C/km) between a layer at a specified interval

Parameters

prof (profile object) – Profile object
lower (number) – Lower bound in height (m)
upper (number) – Upper bound in height (m)
interval (number) – Interval to assess the lapse rate at (m)
depth (number) – Depth of the layer to assess the lapse rate over (m)

Returns

max lapse rate (C/km) (float)
lower pressure of max lapse rate (mb) (number)
upper pressure of max lapse rate (mb) (number)

sharppy.sharptab.params.most_unstable_level(prof, pbot=None, ptop=None, dp=- 1, exact=False)[source]¶

Finds the most unstable level between the lower and upper levels.

Parameters

prof (profile object) – Profile Object
pbot (number (optional; default surface)) – Pressure of the bottom level (hPa)
ptop (number (optional; default 400 hPa)) – Pressure of the top level (hPa)
dp (negative integer (optional; default = -1)) – The pressure increment for the interpolated sounding (mb)
exact (bool (optional; default = False)) – Switch to choose between using the exact data (slower) or using interpolated sounding at ‘dp’ pressure levels (faster)

Returns

Pressure level of most unstable level (hPa)

Return type

number

sharppy.sharptab.params.parcelx(prof, pbot=None, ptop=None, dp=- 1, **kwargs)[source]¶

Lifts the specified parcel, calculates various levels and parameters from the profile object. B+/B- are calculated based on the specified layer. Such parameters include CAPE, CIN, LCL height, LFC height, buoyancy minimum, EL height, MPL height.

!! All calculations use the virtual temperature correction unless noted. !!

Parameters

prof (profile object) – Profile Object
pbot (number (optional; default surface)) – Pressure of the bottom level (hPa)
ptop (number (optional; default 400 hPa)) – Pressure of the top level (hPa)
pres (number (optional)) – Pressure of parcel to lift (hPa)
tmpc (number (optional)) – Temperature of parcel to lift (C)
dwpc (number (optional)) – Dew Point of parcel to lift (C)
dp (negative integer (optional; default = -1)) – The pressure increment for the interpolated sounding (mb)
exact (bool (optional; default = False)) – Switch to choose between using the exact data (slower) or using interpolated sounding at ‘dp’ pressure levels (faster)
flag (number (optional; default = 5)) – Flag to determine what kind of parcel to create; See DefineParcel for flag values
lplvals (lifting parcel layer object (optional)) – Contains the necessary parameters to describe a lifting parcel

Returns

Return type

Parcel Object

sharppy.sharptab.params.bulk_rich(prof, pcl)[source]¶

Calculates the Bulk Richardson Number for a given parcel.

Parameters

prof (profile object) – Profile object
pcl (parcel object) – Parcel object

Returns

Bulk Richardson Number

Return type

number

sharppy.sharptab.params.bunkers_storm_motion(prof, **kwargs)[source]¶

Compute the Bunkers Storm Motion for a right moving supercell using a parcel based approach. This code is consistent with the findings in Bunkers et. al 2014, using the Effective Inflow Base as the base, and 65% of the most unstable parcel equilibrium level height using the pressure weighted mean wind.

Parameters

prof (profile object) – Profile Object
pbot (float (optional)) – Base of effective-inflow layer (hPa)
mupcl (parcel object (optional)) – Most Unstable Layer parcel

Returns

rstu (number) – Right Storm Motion U-component (kts)
rstv (number) – Right Storm Motion V-component (kts)
lstu (number) – Left Storm Motion U-component (kts)
lstv (number) – Left Storm Motion V-component (kts)

sharppy.sharptab.params.effective_inflow_layer(prof, ecape=100, ecinh=- 250, **kwargs)[source]¶

Calculates the top and bottom of the effective inflow layer based on research by 3.

Parameters

prof (profile object) – Profile object
ecape (number (optional; default=100)) – Minimum amount of CAPE in the layer to be considered part of the effective inflow layer.
echine (number (optional; default=250)) – Maximum amount of CINH in the layer to be considered part of the effective inflow layer
mupcl (parcel object) – Most Unstable Layer parcel

Returns

pbot (number) – Pressure at the bottom of the layer (hPa)
ptop (number) – Pressure at the top of the layer (hPa)

sharppy.sharptab.params.convective_temp(prof, **kwargs)[source]¶

Computes the convective temperature, assuming no change in the moisture profile. Parcels are iteratively lifted until only mincinh is left as a cap. The first guess is the observed surface temperature.

Parameters

prof (profile object) – Profile Object
mincinh (parcel object (optional; default -1)) – Amount of CINH left at CI
pres (number (optional)) – Pressure of parcel to lift (hPa)
tmpc (number (optional)) – Temperature of parcel to lift (C)
dwpc (number (optional)) – Dew Point of parcel to lift (C)

Returns

Convective Temperature (C)

Return type

number

sharppy.sharptab.params.esp(prof, **kwargs)[source]¶

Enhanced Stretching Potential (ESP) This composite parameter identifies areas where low-level buoyancy and steep low-level lapse rates are co-located, which may favor low-level vortex stretching and tornado potential.

REQUIRES: 0-3 km MLCAPE (from MLPCL)

Parameters

prof (profile object) – Profile object
mlpcl (parcel object, optional) – Mixed-Layer Parcel object

Returns

ESP Index

Return type

number

sharppy.sharptab.params.pbl_top(prof)[source]¶

Planetary Boundary Layer Depth Adapted from NSHARP code donated by Rich Thompson (SPC)

Calculates the planetary boundary layer depth by calculating the virtual potential temperature of the surface parcel + .5 K, and then searching for the location above the surface where the virtual potential temperature of the profile is greater than the surface virtual potential temperature.

While this routine suggests a parcel lift, this Python adaptation does not use loop like parcelx().

Parameters: prof (profile object) – Profile object
Returns: ppbl_top (mb)
Return type: number

sharppy.sharptab.params.precip_eff(prof, **kwargs)[source]¶

Precipitation Efficiency (*)

This calculation comes from Noel and Dobur 2002, published in NWA Digest Vol 26, No 34.

The calculation multiplies the PW from the whole atmosphere by the 1000 - 700 mb mean relative humidity (in decimal form)

Values on the SPC Mesoanalysis range from 0 to 2.6.

Larger values means that the precipitation is more efficient.

Warning

This function has not been directly compared with a version at SPC.

Parameters

prof (profile object) – Profile object
pwat (number, optional) – precomputed precipitable water vapor (inch)
pbot (number, optional) – the bottom pressure of the RH layer (mb)
ptop (number, optional) – the top pressure of the RH layer (mb)

Returns

precip_efficency (inches)

Return type

number

sharppy.sharptab.params.dcape(prof)[source]¶

Downdraft CAPE (DCAPE)

Adapted from John Hart’s (SPC) DCAPE code in NSHARP donated by Rich Thompson (SPC)

Calculates the downdraft CAPE value using the downdraft parcel source found in the lowest 400 mb of the sounding. This downdraft parcel is found by identifying the minimum 100 mb layer averaged Theta-E.

Afterwards, this parcel is lowered to the surface moist adiabatically (w/o virtual temperature correction) and the energy accumulated is called the DCAPE.

Future adaptations of this function may utilize the Parcel/DefineParcel object.

Parameters

prof (profile object) – Profile object

Returns

dcape (number) – downdraft CAPE (J/kg)
ttrace (array) – downdraft parcel trace temperature (C)
ptrace (array) – downdraft parcel trace pressure (mb)

sharppy.sharptab.params.sig_severe(prof, **kwargs)[source]¶

Significant Severe (SigSevere) Craven and Brooks, 2004

Parameters

prof (profile object) – Profile object
mlpcl (parcel object, optional) – Mixed-Layer Parcel object

Returns

significant severe parameter (m3/s3)

Return type

number

sharppy.sharptab.params.dgz(prof)[source]¶

Dendritic Growth Zone Levels

This function finds the pressure levels for the dendritic growth zone (from -12 C to -17 C). If either temperature cannot be found, it is set to be the surface pressure.

Parameters

prof (profile object) – Profile Object

Returns

pbot (number) – Pressure of the bottom level (mb)
ptop (number) – Pressure of the top level (mb)

sharppy.sharptab.params.ship(prof, **kwargs)[source]¶

Calculate the Sig Hail Parameter (SHIP)

Ryan Jewell (SPC) helped in correcting this equation as the SPC sounding help page version did not have the correct information of how SHIP was calculated.

The significant hail parameter (SHIP; SPC 2014) is an index developed in-house at the SPC. (Johnson and Sugden 2014)

Parameters

prof (profile object) – Profile object
mupcl (parcel object, optional) – Most Unstable Parcel object
lr75 (float, optional) – 700 - 500 mb lapse rate (C/km)
h5_temp (float, optional) – 500 mb temperature (C)
shr06 (float, optional) – 0-6 km shear (m/s)
frz_lvl (float, optional) – freezing level (m)

Returns

ship – significant hail parameter (unitless)

Return type

number

sharppy.sharptab.params.stp_cin(mlcape, esrh, ebwd, mllcl, mlcinh)[source]¶

Significant Tornado Parameter (w/CIN)

Formulated using the methodology outlined in 1. Used to detect environments where significant tornadoes are possible within the United States. Uses the effective inflow layer calculations in 3 and was created as an alternative to 2.

1: Thompson, R. L., B. T. Smith, J. S. Grams, A. R. Dean, and C. Broyles, 2012: Convective modes for significant severe thunderstorms in the contiguous United States.Part II: Supercell and QLCS tornado environments. Wea. Forecasting, 27, 1136–1154,doi:https://doi.org/10.1175/WAF-D-11-00116.1.
3(1,2): Thompson, R. L., C. M. Mead, and R. Edwards, 2007: Effective storm-relative helicity and bulk shear in supercell thunderstorm environments. Wea. Forecasting, 22, 102–115, doi:https://doi.org/10.1175/WAF969.1.

Parameters

mlcape (float) – Mixed-layer CAPE from the parcel class (J/kg)
esrh (float) – effective storm relative helicity (m2/s2)
ebwd (float) – effective bulk wind difference (m/s)
mllcl (float) – mixed-layer lifted condensation level (m)
mlcinh (float) – mixed-layer convective inhibition (J/kg)

Returns

stp_cin – significant tornado parameter (unitless)

Return type

number

sharppy.sharptab.prof_collection module¶

Code that describes the “Profile Collection” objects that is used by the sharppy.io.decoders and the SHARPpy GUI. This is essentially an object that is a collection of Profile objects.

class sharppy.sharptab.prof_collection.ProfCollection(profiles, dates, target_type=<class 'sharppy.sharptab.profile.ConvectiveProfile'>, **kwargs)[source]¶

Bases: object

ProfCollection: A class to keep track of profiles from a single data source. Handles time switching, ensemble member switching,: and modifications to profiles.

advanceHighlight(direction)[source]¶: Change which member is highlighted. direction: An integer (either 1 or -1) specifying which direction to go in the list. The list is in

alphabetical order, so the members will be gone through in that order.

advanceTime(direction)[source]¶: Advance time in a direction specified by ‘direction’. Returns a datetime object containing the new time. direction: An integer (ether 1 or -1) specifying which direction to move time in. 1 moves time forward,

-1 moves time backward.

cancelCopy()[source]¶: Terminates any threads that are running in the background.

defineUserParcel(parcel)[source]¶: Defines a custom parcel for the current profile. parcel: A parcel object to use as the custom parcel.

getAnalogDate()[source]¶: If this is an analog, return the date of the analog. Otherwise, returns None.

getCurrentDate()[source]¶: Returns the current date in the profile object

getCurrentProfs()[source]¶: Returns the profiles at the current time.

getHighlightedMemberName()[source]¶: Gets the name of the member that is currently highlighted.

getHighlightedProf()[source]¶: Returns which profile is highlighted.

getMeta(key, index=False)[source]¶: Returns metadata about the profile. key: What metadata to return. index [optional]: If true, treat the metadata as an array with the same length as dates passed in the constructor.

Returns value of that array at this time index..

hasCurrentProf()[source]¶: Returns True if the collection has a profile at the current time. Otherwise, returns False.

hasMeta(key)[source]¶: Returns True if the collection has metadata corresponding to ‘key’. Otherwise returns False.

interp(dp=- 25)[source]¶: Interpolate the profile object to a specific pressure level spacing.

isEnsemble()[source]¶: Returns True if this collection has multiple ensemble members. Otherwise, returns False.

isInterpolated()[source]¶: Returns True if the profiles at the current time have been modified. Returns False otherwise.

isModified()[source]¶: Returns True if the profiles at the current time have been modified. Returns False otherwise.

modify(idx, **kwargs)[source]¶

Modify the profile at the current time. idx: The vertical index to modify **kwargs: The variables to modify (‘tmpc’, ‘dwpc’, ‘u’, or ‘v’)

TODO: Allow modification of layers. Could be that idx is -999 for layer: and kwargs passes information about the layers to be modified.

modifyStormMotion(deviant, vec_u, vec_v)[source]¶

resetInterpolation()[source]¶

resetModification(*args)[source]¶: Reset the profile to its original state. *args: The variables to reset (‘tmpc’, ‘dwpc’, ‘u’, or ‘v’).

resetStormMotion()[source]¶

setAnalogToDate(analog_to_date)[source]¶

Specify that this collection represents an analog; the date is set to ‘analog_to_date’, and the: analog date is set to the former date.

analog_to_date: A datetime object that specifies the date to which this collection is an analog.

setAsync(async_obj)[source]¶

Start an asynchronous process to load objects of type ‘target_type’ in the background. Used to upgrade the Profile objects to ConvectiveProfile objects in the background

async: An AsyncThreads instance.

setCurrentDate(cur_dt)[source]¶: Sets the current date to be ‘cur_dt’. cur_dt: A datetime object specifiying which date to set it to.

setHighlightedMember(member_name)[source]¶: Sets the highlighted ensemble member to be ‘member_name’.

setMeta(key, value)[source]¶: Sets the metadata ‘key’ to ‘value’.

subset(idxs)[source]¶: Subset the profile collection over time. idxs: The time indices to include in the subsetted collection.

sharppy.sharptab.prof_collection.doCopy(target_type, prof, idx, pipe)[source]¶

sharppy.sharptab.profile module¶

Contains code to create the Profile objects.

Create the Sounding (Profile) Object

class sharppy.sharptab.profile.BasicProfile(**kwargs)[source]¶

Bases: sharppy.sharptab.profile.Profile

The default data class for SHARPpy. All other data classes inherit from this class. This class holds the vertical data for pressure, height, temperature, dewpoint, and winds. This class has no indices computed.

get_rh_profile()[source]¶

Function to calculate the relative humidity profile

Parameters: None –
Returns
Return type: Array of the relative humidity profile

get_sfc()[source]¶

Convenience function to get the index of the surface. It is determined by finding the lowest level in which a temperature is reported.

Parameters: None –
Returns
Return type: Index of the surface

get_theta_profile()[source]¶

Function to calculate the theta profile.

Parameters: None –
Returns
Return type: Array of theta profile

get_thetae_profile()[source]¶

Function to calculate the theta-e profile.

Parameters: None –
Returns
Return type: Array of theta-e profile

get_top()[source]¶

Convenience function to get the index of the surface. It is determined by finding the lowest level in which a temperature is reported.

Parameters: None –
Returns
Return type: Index of the surface

get_wetbulb_profile()[source]¶

Function to calculate the wetbulb profile.

Parameters: None –
Returns
Return type: Array of wet bulb profile

get_wvmr_profile()[source]¶

Function to calculate the water vapor mixing ratio profile.

Parameters: None –
Returns
Return type: Array of water vapor mixing ratio profile

class sharppy.sharptab.profile.ConvectiveProfile(**kwargs)[source]¶

Bases: sharppy.sharptab.profile.BasicProfile

The Convective data class for SHARPPy. This is the class used to generate the indices that are default for the SPC NSHARP display.

This class inherits from the Profile object.

get_PWV_loc()[source]¶

Function to compute the location of the current PWV with respect to it’s sounding climatology from Bunkers.

Parameters: None –
Returns
Return type: None

get_fire()[source]¶

Function to generate different indices and information regarding any fire weather in the sounding. This helps fill the data shown in the FIRE inset.

Parameters: None –
Returns
Return type: None

get_indices()[source]¶

Function to set any additional indices that are included in the thermo window.

Parameters: None –
Returns
Return type: None

get_kinematics()[source]¶

Function to generate the numerous kinematic quantities used for display and calculations. It requires that the parcel calculations have already been called for the lcl to el shear and mean wind vectors, as well as indices that require an effective inflow layer.

Parameters: None –
Returns
Return type: None

get_parcels()[source]¶

Function to generate various parcels and parcel traces. Returns nothing, but sets the following variables:

self.mupcl : Most Unstable Parcel self.sfcpcl : Surface Based Parcel self.mlpcl : Mixed Layer Parcel self.fcstpcl : Forecast Surface Parcel self.ebottom : The bottom pressure level of the effective inflow layer self.etop : the top pressure level of the effective inflow layer self.ebotm : The bottom, meters (agl), of the effective inflow layer self.etopm : The top, meters (agl), of the effective inflow layer

Parameters: None –
Returns
Return type: None

get_precip()[source]¶

Function to generate different indices and information regarding any precipitation in the sounding. This helps fill the data shown in the WINTER inset.

Returns nothing, but sets the following variables:

self.dgz_pbot, self.dgz_ptop : the dendretic growth zone (DGZ) top and bottom (mb) self.dgz_meanrh : DGZ mean relative humidity (%) self.dgz_pw : the preciptable water vapor in the DGZ (inches) self.dgz_meanq : the mean water vapor mixing ratio in the DGZ (g/kg) self.dgz_meanomeg : the mean omega in the DGZ (microbars/second) self.oprh : the OPRH variable (units don’t mean anything) self.plevel, self.phase, self.tmp, self.st : the initial phase, level, temperature, and state of any precip in the sounding self.tpos, self.tneg, self.ttop, self.tbot : positive and negative temperature layers in the sounding self.wpos, self.wneg, self.wtop, self.wbot : positive and negative wetbulb layers in the soundings self.precip_type : the best guess precipitation type

Parameters: None –
Returns
Return type: None

get_sars()[source]¶

Function to get the SARS analogues from the hail and supercell databases. Requires calling get_kinematics() and get_parcels() first. Also calculates the significant hail parameter.

Function returns nothing, but sets the following variables:

self.matches - the matches from SARS HAIL self.ship - significant hail parameter self.supercell_matches - the matches from SARS SUPERCELL

Parameters: None –
Returns
Return type: None

get_severe()[source]¶

Function to calculate special severe weather indices. Requires calling get_parcels() and get_kinematics().

Returns nothing, but sets the following variables:

self.right_stp_fixed - fixed layer significant tornado parameter (computed with SRH relative to the right-mover vector) self.left_stp_fixed - fixed layer significant tornado parameter (computed with SRH relative to the left-mover vector) self.right_stp_cin - effective layer significant tornado parameter (computed with SRH relative to the right-mover vector) self.left_stp_cin - effective layer significant tornado parameter (computed with SRH relative to the left-mover vector) self.right_scp - right moving supercell composite parameter self.left_scp - left moving supercell composite parameter

Parameters: None –
Returns
Return type: None

get_thermo()[source]¶

Function to generate thermodynamic indices.

Function returns nothing, but sets the following variables:

self.k_idx - K Index, a severe weather index self.pwat - Precipitable Water Vapor (inches) self.lapserate_3km - 0 to 3km AGL lapse rate (C/km) self.lapserate_3_6km - 3 to 6km AGL lapse rate (C/km) self.lapserate_850_500 - 850 to 500mb lapse rate (C/km) self.lapserate_700_500 - 700 to 500mb lapse rate (C/km) self.convT - The Convective Temperature (F) self.maxT - The Maximum Forecast Surface Temp (F) self.mean_mixr - Mean Mixing Ratio self.low_rh - low level mean relative humidity self.mid_rh - mid level mean relative humidity self.totals_totals - Totals Totals index, a severe weather index

Parameters: None –
Returns
Return type: None

get_traj()[source]¶

Function to compute the storm slinky profile using the trajectory model.

self.slinky_traj - the list containing the position vector for the updraft self.updraft_tilt - the updraft tilt (an angle) with respect to the horizon

Parameters: None –
Returns
Return type: None

get_watch()[source]¶

Function to get the possible watch type. Function returns nothing, but sets the following variables:

self.watch_type - possible watch type

Parameters: None –
Returns
Return type: None

reset_srm()[source]¶

Resets the storm motion vector to those found by the Bunkers algorithm

Parameters: None –
Returns
Return type: None

set_srleft(lm_u, lm_v)[source]¶

Sets the u and v values of the left mover supercell storm motion vector.

Parameters

lm_u (number) – Left mover u-component of the storm motion vector
lm_v (number) – Left mover v-component of the storm motion vector

Returns

Return type

None

set_srright(rm_u, rm_v)[source]¶

Sets the u and v values of the right mover supercell storm motion vector.

Parameters

rm_u (number) – Right mover u-component of the storm motion vector
rm_v (number) – Right mover v-component of the storm motion vector

Returns

Return type

None

class sharppy.sharptab.profile.Profile(**kwargs)[source]¶

Bases: object

checkDataIntegrity()[source]¶

classmethod copy(prof, strictQC=False, **kwargs)[source]¶: Copies a profile object.

toFile(file_name)[source]¶

sharppy.sharptab.profile.create_profile(**kwargs)[source]¶

This is a wrapper function for constructing Profile objects and objects that inherit from the Profile class. This will construct and return the appropriate Profile object based on the supplied keyword argument. If no profile keyword is supplied, it defaults to a basic Profile. This also requires that you pass through all the relevant keyword arguments for the constructors to the Profile objects and the objects that inherit from Profile.

Parameters

Keywords (Optional) –
pres (array_like) – The pressure values (Hectopascals)
hght (array_like) – The corresponding height values (Meters)
tmpc (array_like) – The corresponding temperature values (Celsius)
dwpc (array_like) – The corresponding dewpoint temperature values (Celsius)
Keyword Pairs (must use one or the other) (Optional) –
wdir (array_like) – The direction from which the wind is blowing in meteorological degrees
wspd (array_like) – The speed of the wind (kts)
OR –
u (array_like) – The U-component of the direction from which the wind is blowing. (kts)
v (array_like) – The V-component of the direction from which the wind is blowing. (kts)
Keywords –
missing (number, optional (default: sharppy.sharptab.constants.MISSING)) – The value of the missing flag used in the Profile objects
profile (string, optional (default: 'default')) – The text identifier for the Profile to be generated. Valid options include (‘default’ | ‘basic’ | ‘convective’). Default will construct a basic Profile, and convective will construct a ConvectiveProfile used for the SPC style GUI.
omeg (array_like) – The corresponding vertical velocity values (Pa/s)

Returns

Profile (a basic Profile object) – This is the most basic and default object.
OR
ConvectiveProfile (a child of Profile) – This is the class used for the SPC GUI.

sharppy.sharptab.thermo module¶

Contains code to perform thermodynamic routines (i.e. saturated lifting, dry lifting, calculation of dewpoint, mixing ratio, equivalent potential temperature)

Thermodynamic Library

sharppy.sharptab.thermo.drylift(p, t, td)[source]¶

Lifts a parcel to the LCL and returns its new level and temperature.

Parameters

p (number, numpy array) – Pressure of initial parcel in hPa
t (number, numpy array) – Temperature of inital parcel in C
td (number, numpy array) – Dew Point of initial parcel in C

Returns

p2 (number, numpy array) – LCL pressure in hPa
t2 (number, numpy array) – LCL Temperature in C

sharppy.sharptab.thermo.thalvl(theta, t)[source]¶

Returns the level (hPa) of a parcel.

Parameters

theta (number, numpy array) – Potential temperature of the parcel (C)
t (number, numpy array) – Temperature of the parcel (C)

Returns

Return type

Pressure Level (hPa [float]) of the parcel

sharppy.sharptab.thermo.lcltemp(t, td)[source]¶

Returns the temperature (C) of a parcel when raised to its LCL.

Parameters

t (number, numpy array) – Temperature of the parcel (C)
td (number, numpy array) – Dewpoint temperature of the parcel (C)

Returns

Return type

Temperature (C) of the parcel at it’s LCL.

sharppy.sharptab.thermo.theta(p, t, p2=1000.0)[source]¶

Returns the potential temperature (C) of a parcel.

Parameters

p (number, numpy array) – The pressure of the parcel (hPa)
t (number, numpy array) – Temperature of the parcel (C)
p2 (number, numpy array (default 1000.)) – Reference pressure level (hPa)

Returns

Return type

Potential temperature (C)

sharppy.sharptab.thermo.wobf(t)[source]¶

Implementation of the Wobus Function for computing the moist adiabats.

Caution

The Wobus function has been found to have a slight pressure dependency (Davies-Jones 2008). This dependency is not included in this implementation.

Parameters: t (number, numpy array) – Temperature (C)
Returns
Return type: Correction to theta (C) for calculation of saturated potential temperature.

sharppy.sharptab.thermo.satlift(p, thetam, conv=0.1)[source]¶

Returns the temperature (C) of a saturated parcel (thm) when lifted to a new pressure level (hPa)

Caution

Testing of the SHARPpy parcel lifting routines has revealed that the convergence criteria used the SHARP version (and implemented here) may cause drifting the pseudoadiabat to occasionally “drift” when high-resolution radiosonde data is used. While a stricter convergence criteria (e.g. 0.01) has shown to resolve this problem, it creates a noticable departure from the SPC CAPE values and therefore may decalibrate the other SHARPpy functions (e.g. SARS).

Parameters

p (number) – Pressure to which parcel is raised (hPa)
thetam (number) – Saturated Potential Temperature of parcel (C)
conv (number) – Convergence criteria for satlift() (C)

Returns

Return type

Temperature (C) of saturated parcel at new level

sharppy.sharptab.thermo.wetlift(p, t, p2)[source]¶

Lifts a parcel moist adiabatically to its new level.

Parameters

p (number) – Pressure of initial parcel (hPa)
t (number) – Temperature of initial parcel (C)
p2 (number) – Pressure of final level (hPa)

Returns

Return type

Temperature (C)

sharppy.sharptab.thermo.lifted(p, t, td, lev)[source]¶

Calculate temperature (C) of parcel (defined by p, t, td) lifted to the specified pressure level.

Parameters

p (number) – Pressure of initial parcel in hPa
t (number) – Temperature of initial parcel in C
td (number) – Dew Point of initial parcel in C
lev (number) – Pressure to which parcel is lifted in hPa

Returns

Return type

Temperature (C) of lifted parcel

sharppy.sharptab.thermo.vappres(t)[source]¶

Returns the vapor pressure of dry air at given temperature

Parameters: t (number, numpy array) – Temperature of the parcel (C)
Returns
Return type: Vapor Pressure of dry air

sharppy.sharptab.thermo.mixratio(p, t)[source]¶

Returns the mixing ratio (g/kg) of a parcel

Parameters

p (number, numpy array) – Pressure of the parcel (hPa)
t (number, numpy array) – Temperature of the parcel (hPa)

Returns

Return type

Mixing Ratio (g/kg) of the given parcel

sharppy.sharptab.thermo.temp_at_mixrat(w, p)[source]¶

Returns the temperature (C) of air at the given mixing ratio (g/kg) and pressure (hPa)

Parameters

w (number, numpy array) – Mixing Ratio (g/kg)
p (number, numpy array) – Pressure (hPa)

Returns

Return type

Temperature (C) of air at given mixing ratio and pressure

sharppy.sharptab.thermo.wetbulb(p, t, td)[source]¶

Calculates the wetbulb temperature (C) for the given parcel

Parameters

p (number) – Pressure of parcel (hPa)
t (number) – Temperature of parcel (C)
td (number) – Dew Point of parcel (C)

Returns

Return type

Wetbulb temperature (C)

sharppy.sharptab.thermo.thetaw(p, t, td)[source]¶

Returns the wetbulb potential temperature (C) of a parcel.

Parameters

p (number) – The pressure of the parcel (hPa)
t (number) – Temperature of the parcel (C)
td (number) – Dew point of parcel (C)

Returns

Return type

Wetbulb potential temperature (C)

sharppy.sharptab.thermo.thetae(p, t, td)[source]¶

Returns the equivalent potential temperature (C) of a parcel.

Parameters

p (number) – The pressure of the parcel (hPa)
t (number) – Temperature of the parcel (C)
td (number) – Dew point of parcel (C)

Returns

Return type

Equivalent potential temperature (C)

sharppy.sharptab.thermo.virtemp(p, t, td)[source]¶

Returns the virtual temperature (C) of a parcel. If td is masked, then it returns the temperature passed to the function.

Parameters

p (number) – The pressure of the parcel (hPa)
t (number) – Temperature of the parcel (C)
td (number) – Dew point of parcel (C)

Returns

Return type

Virtual temperature (C)

sharppy.sharptab.thermo.relh(p, t, td)[source]¶

Returns the virtual temperature (C) of a parcel.

Parameters

p (number) – The pressure of the parcel (hPa)
t (number) – Temperature of the parcel (C)
td (number) – Dew point of parcel (C)

Returns

Return type

Relative humidity (%) of a parcel

sharppy.sharptab.thermo.ftoc(t)[source]¶

Convert temperature from Fahrenheit to Celsius

Parameters: t (number, numpy array) – The temperature in Fahrenheit
Returns
Return type: Temperature in Celsius (number or numpy array)

sharppy.sharptab.thermo.ctof(t)[source]¶

Convert temperature from Celsius to Fahrenheit

Parameters: t (number, numpy array) – The temperature in Celsius
Returns
Return type: Temperature in Fahrenheit (number or numpy array)

sharppy.sharptab.thermo.ctok(t)[source]¶

Convert temperature from Celsius to Kelvin

Parameters: t (number, numpy array) – The temperature in Celsius
Returns
Return type: Temperature in Kelvin (number or numpy array)

sharppy.sharptab.thermo.ktoc(t)[source]¶

Convert temperature from Kelvin to Celsius

Parameters: t (number, numpy array) – The temperature in Kelvin
Returns
Return type: Temperature in Celsius (number or numpy array)

sharppy.sharptab.thermo.ftok(t)[source]¶

Convert temperature from Fahrenheit to Kelvin

Parameters: t (number, numpy array) – The temperature in Fahrenheit
Returns
Return type: Temperature in Kelvin (number or numpy array)

sharppy.sharptab.thermo.ktof(t)[source]¶

Convert temperature from Kelvin to Fahrenheit

Parameters: t (number, numpy array) – The temperature in Kelvin
Returns
Return type: Temperature in Fahrenheit (number or numpy array)

sharppy.sharptab.utils module¶

Contains helper functions to convert data types.

Frequently used functions

sharppy.sharptab.utils.INT2STR(val)[source]¶

Convert a value (float or int) into an integer string by rounding to the nearest integer and returning the string. Used to handle case where value is nan or masked.

Parameters: val (float or int) –
Returns
Return type: Val rounded to the nearest int and converted to a string.

sharppy.sharptab.utils.FLOAT2STR(val, precision)[source]¶

Convert a value (float or int) into a float string to the decimal place of a specified precision. Used to handle the case where the value is nan or masked.

Parameters

val (float or int) –
precision (int) – used to specify the precision of the resulting rounded value

Returns

val rounded to the nearest specified decimal place and converted
to a string.

sharppy.sharptab.utils.MS2KTS(val)[source]¶

Convert meters per second to knots

Parameters: val (float, numpy_array) – Speed (m/s)
Returns
Return type: Val converted to knots (float)

sharppy.sharptab.utils.KTS2MS(val)[source]¶

Convert knots to meters per second

Parameters: val (float, numpy_array) – Speed (kts)
Returns
Return type: Val converted to meters per second (float)

sharppy.sharptab.utils.MS2MPH(val)[source]¶

Convert meters per second to miles per hour

Parameters: val (float, numpy_array) – Speed (m/s)
Returns
Return type: Val converted to miles per hour (float)

sharppy.sharptab.utils.MPH2MS(val)[source]¶

Convert miles per hour to meters per second

Parameters: val (float, numpy_array) – Speed (mph)
Returns
Return type: Val converted to meters per second (float)

sharppy.sharptab.utils.MPH2KTS(val)[source]¶

Convert miles per hour to knots

Parameters: val (float, numpy_array) – Speed (mph)
Returns
Return type: Val converted to knots (float)

sharppy.sharptab.utils.KTS2MPH(val)[source]¶

Convert knots to miles per hour

Parameters: val (float, numpy_array) – Speed (kts)
Returns
Return type: Val converted to miles per hour (float)

sharppy.sharptab.utils.M2FT(val)[source]¶

Convert meters to feet

Parameters: val (float, numpy_array) – Distance (m)
Returns
Return type: Val converted to feet (float)

sharppy.sharptab.utils.FT2M(val)[source]¶

Convert feet to meters

Parameters: val (float, numpy_array) – Distance (ft)
Returns
Return type: Val converted to meters (float)

sharppy.sharptab.utils.IN2CM(val)[source]¶

Convert inches to centimeters

Parameters: val (float, numpy_array) – Distance (inches)
Returns
Return type: Val converted to centimeters (float)

sharppy.sharptab.utils.CM2IN(val)[source]¶

Convert centimeters to inches

Parameters: val (float, numpy_array) – Distance (centimeters)
Returns
Return type: Val converted to inches (float)

sharppy.sharptab.utils.vec2comp(wdir, wspd, missing=- 9999.0)[source]¶

Convert direction and magnitude into U, V components

Parameters

wdir (number, array_like) – Angle in meteorological degrees
wspd (number, array_like) – Magnitudes of wind vector (input units == output units)
missing (number (optional)) – Optional missing parameter. If not given, assume default missing value from sharppy.sharptab.constants.MISSING

Returns

u (number, array_like (same as input)) – U-component of the wind (units are the same as those of input speed)
v (number, array_like (same as input)) – V-component of the wind (units are the same as those of input speed)

sharppy.sharptab.utils.comp2vec(u, v, missing=- 9999.0)[source]¶

Convert U, V components into direction and magnitude

Parameters

u (number, array_like) – U-component of the wind
v (number, array_like) – V-component of the wind
missing (number (optional)) – Optional missing parameter. If not given, assume default missing value from sharppy.sharptab.constants.MISSING

Returns

wdir (number, array_like (same as input)) – Angle in meteorological degrees
wspd (number, array_like (same as input)) – Magnitudes of wind vector (input units == output units)

sharppy.sharptab.utils.mag(u, v, missing=- 9999.0)[source]¶

Compute the magnitude of a vector from its components

Parameters

u (number, array_like) – U-component of the wind
v (number, array_like) – V-component of the wind
missing (number (optional)) – Optional missing parameter. If not given, assume default missing value from sharppy.sharptab.constants.MISSING

Returns

mag – The magnitude of the vector (units are the same as input)

Return type

number, array_like

sharppy.sharptab.utils.QC(val)[source]¶: Tests if a value is masked.

sharppy.sharptab.watch_type module¶

Contains functions to calculate the possible hazard type and precipitation type values (for the Winter inset).

sharppy.sharptab.watch_type.best_guess_precip(prof, init_phase, init_lvl, init_temp, tpos, tneg)[source]¶

Best Guess Precipitation type Adapted from SHARP code donated by Rich Thompson (SPC)

This algorithm utilizes the output from the init_phase() and posneg_temperature() functions to make a best guess at the preciptation type one would observe at the surface given a thermodynamic profile.

Precipitation Types Supported: * None * Rain * Snow * Sleet and Snow * Sleet * Freezing Rain/Drizzle * Unknown

Parameters

prof (profile object) – Profile object
init_phase (int) – the initial phase of the precipitation (see 2nd value returned from init_phase())
init_lvl (float) – the initial level of the precipitation source (mb) (see 1st value returned from init_phase())
init_temp (float) – the initial level of the precipitation source (C) (see 3rd value returned from init_phase())
tpos (float) – the positive area (> 0 C) in the temperature profile (J/kg)

Returns

precip_type – the best guess precipitation type

Return type

str

sharppy.sharptab.watch_type.heat_index(temp, rh)[source]¶

Heat Index Equation

Computes the heat index using the equation obtained by performing multiple linear regression on the table in Steadman 1979.

Referenced from: http://www.srh.noaa.gov/images/ffc/pdf/ta_htindx.PDF

Parameters

temp (number) – temperature (F)
rh (number) – relative humidity (%)

Returns

heat_index – heat index value in (F)

Return type

number

sharppy.sharptab.watch_type.init_phase(prof)[source]¶

Inital Precipitation Phase Adapted from SHARP code donated by Rich Thompson (SPC)

This function determines the initial phase of any precipitation source in the profile. It does this either by finding a source of precipitation by searching for the highest 50 mb layer that has a relative humidity greater than 80 percent at the top and the bottom of the layer. This layer may be found either in the lowest 5 km of the profile, and if an OMEG profile is specified in the profile object, it will search for the layers with upward motion.

The precipitation type is determined by using a.) the interpolated temperature in the middle of the precipitation source layer and b.) set temperature thresholds to determine the precipitation type. The type may be “Rain”, “Freezing Rain”, “ZR/S Mix”, or “Snow”.

Parameters

prof (profile object) – Profile object (omega profile optional)

Returns

plevel (number) – the pressure level of the precipitation source (mb)
phase (int) – the phase type of the precipitation (int), phase = 0 for “Rain”, phase = 1 for “Freezing Rain” or “ZR/S Mix”, phase = 3 for “Snow”
tmp (number) – the temperature at the level that is the precipitation source (C)
st (str) – a string naming the precipitation type

sharppy.sharptab.watch_type.posneg_temperature(prof, start=- 1)[source]¶

Positive/Negative Temperature profile Adapted from SHARP code donated by Rich Thompson (SPC)

Description: This routine calculates the positive (above 0 C) and negative (below 0 C) areas of the temperature profile starting from a specified pressure (start). If the specified pressure is not given, this routine calls init_phase() to obtain the pressure level the precipitation expected to fall begins at.

This is an routine considers only the temperature profile as opposed to the wet-bulb profile.

Parameters

prof (profile object) – Profile object
start (number) – the pressure level the precipitation originates from (found by calling init_phase()) (mb)

Returns

pos (float) – the positive area (> 0 C) of the wet-bulb profile (J/kg)
neg (float) – the negative area (< 0 C) of the wet-bulb profile (J/kg)
top (float) – the top of the precipitation layer pressure (mb)
bot (float) – the bottom of the precipitation layer pressure (mb)

sharppy.sharptab.watch_type.posneg_wetbulb(prof, start=- 1)[source]¶

Positive/Negative Wetbulb profile Adapted from SHARP code donated by Rich Thompson (SPC)

This routine calculates the positive (above 0 C) and negative (below 0 C) areas of the wet bulb profile starting from a specified pressure (start). If the specified pressure is not given, this routine calls init_phase() to obtain the pressure level the precipitation expected to fall begins at.

This is an routine considers the wet-bulb profile instead of the temperature profile in case the profile beneath the profile beneath the falling precipitation becomes saturated.

Parameters

prof (profile object) – Profile object
start (number) – the pressure level the precipitation originates from (found by calling init_phase()) (mb)

Returns

pos (float) – the positive area (> 0 C) of the wet-bulb profile (J/kg)
neg (float) – the negative area (< 0 C) of the wet-bulb profile (J/kg)
top (float) – the top of the precipitation layer pressure (mb)
bot (float) – the bottom of the precipitation layer pressure (mb)

sharppy.sharptab.watch_type.possible_watch(prof, use_left=False)[source]¶

Possible Weather/Hazard/Watch Type

This function generates a list of possible significant weather types one can expect given a Profile object. (Currently works only for ConvectiveProfile.)

These possible weather types are computed via fuzzy logic through set thresholds that have been found through a.) analyzing ingredients within the profile and b.) combining those ingredients with forecasting experience to produce a suggestion of what hazards may exist. Some of the logic is based on experience, some of it is based on actual National Weather Service criteria.

This function has not been formally verified and is not meant to be comprehensive nor a source of strict guidance for weather forecasters. As always, the raw data is to be consulted.

Wx Categories (ranked in terms of severity): * PDS TOR * TOR * MRGL TOR * SVR * MRGL SVR * FLASH FLOOD * BLIZZARD * EXCESSIVE HEAT

Suggestions for severe/tornado thresholds were contributed by Rich Thompson - NOAA Storm Prediction Center

Parameters

prof (profile object) – ConvectiveProfile object
use_left (bool) – If True, uses the parameters computed from the left-mover bunkers vector to decide the watch type. If False, uses parameters from the right-mover vector. The default is False.

Returns

watch_types – strings containing the weather types in code

Return type

numpy array

sharppy.sharptab.watch_type.wind_chill(prof)[source]¶

Surface Wind Chill Equation

Computes wind chill at the surface data point in the profile object using the equation found at:

www.nws.noaa.gov/os/windchill/index.shtml

Parameters: prof (profile object) – Profile object
Returns: wind_chill – wind chill value in (F)
Return type: number

sharppy.sharptab.winds module¶

Contains functions to analyze the wind data of Profile objects. Contains routines to calculate wind shear, pressure-weighted mean winds, storm-relative helicity, and critical angle.

Wind Manipulation Routines

sharppy.sharptab.winds.mean_wind(prof, pbot=850, ptop=250, dp=- 1, stu=0, stv=0)[source]¶

Calculates a pressure-weighted mean wind through a layer. The default layer is 850 to 200 hPa.

Parameters

prof (profile object) – Profile object
pbot (number (optional; default 850 hPa)) – Pressure of the bottom level (hPa)
ptop (number (optional; default 250 hPa)) – Pressure of the top level (hPa)
dp (negative integer (optional; default -1)) – The pressure increment for the interpolated sounding
stu (number (optional; default 0)) – U-component of storm-motion vector (kts)
stv (number (optional; default 0)) – V-component of storm-motion vector (kts)

Returns

mnu (number) – U-component (kts)
mnv (number) – V-component (kts)

sharppy.sharptab.winds.mean_wind_npw(prof, pbot=850.0, ptop=250.0, dp=- 1, stu=0, stv=0)[source]¶

Calculates a non-pressure-weighted mean wind through a layer. The default layer is 850 to 200 hPa.

Parameters

prof (profile object) – Profile object
pbot (number (optional; default 850 hPa)) – Pressure of the bottom level (hPa)
ptop (number (optional; default 250 hPa)) – Pressure of the top level (hPa)
dp (negative integer (optional; default -1)) – The pressure increment for the interpolated sounding (mb)
stu (number (optional; default 0)) – U-component of storm-motion vector (kts)
stv (number (optional; default 0)) – V-component of storm-motion vector (kts)

Returns

mnu (number) – U-component (kts)
mnv (number) – V-component (kts)

sharppy.sharptab.winds.sr_wind(prof, pbot=850, ptop=250, stu=0, stv=0, dp=- 1)[source]¶

Calculates a pressure-weighted mean storm-relative wind through a layer. The default layer is 850 to 200 hPa. This is a thin wrapper around mean_wind().

Parameters

prof (profile object) – Profile object
pbot (number (optional; default 850 hPa)) – Pressure of the bottom level (hPa)
ptop (number (optional; default 250 hPa)) – Pressure of the top level (hPa)
stu (number (optional; default 0)) – U-component of storm-motion vector (kts)
stv (number (optional; default 0)) – V-component of storm-motion vector (kts)
dp (negative integer (optional; default -1)) – The pressure increment for the interpolated sounding (mb)

Returns

mnu (number) – U-component (kts)
mnv (number) – V-component (kts)

sharppy.sharptab.winds.sr_wind_npw(prof, pbot=850, ptop=250, stu=0, stv=0, dp=- 1)[source]¶

Calculates a none-pressure-weighted mean storm-relative wind through a layer. The default layer is 850 to 200 hPa. This is a thin wrapper around mean_wind_npw().

Parameters

prof (profile object) – Profile object
pbot (number (optional; default 850 hPa)) – Pressure of the bottom level (hPa)
ptop (number (optional; default 250 hPa)) – Pressure of the top level (hPa)
stu (number (optional; default 0)) – U-component of storm-motion vector (kts)
stv (number (optional; default 0)) – V-component of storm-motion vector (kts)
dp (negative integer (optional; default -1)) – The pressure increment for the interpolated sounding (mb)

Returns

mnu (number) – U-component (kts)
mnv (number) – V-component (kts)

sharppy.sharptab.winds.wind_shear(prof, pbot=850, ptop=250)[source]¶

Calculates the shear between the wind at (pbot) and (ptop).

Parameters

prof (profile object) – Profile object
pbot (number (optional; default 850 hPa)) – Pressure of the bottom level (hPa)
ptop (number (optional; default 250 hPa)) – Pressure of the top level (hPa)

Returns

shu (number) – U-component (kts)
shv (number) – V-component (kts)

sharppy.sharptab.winds.helicity(prof, lower, upper, stu=0, stv=0, dp=- 1, exact=True)[source]¶

Calculates the relative helicity (m2/s2) of a layer from lower to upper. If storm-motion vector is supplied, storm-relative helicity, both positve and negative, is returned.

Parameters

prof (profile object) – Profile Object
lower (number) – Bottom level of layer (m, AGL)
upper (number) – Top level of layer (m, AGL)
stu (number (optional; default = 0)) – U-component of storm-motion (kts)
stv (number (optional; default = 0)) – V-component of storm-motion (kts)
dp (negative integer (optional; default -1)) – The pressure increment for the interpolated sounding (mb)
exact (bool (optional; default = True)) – Switch to choose between using the exact data (slower) or using interpolated sounding at ‘dp’ pressure levels (faster)

Returns

phel+nhel (number) – Combined Helicity (m2/s2)
phel (number) – Positive Helicity (m2/s2)
nhel (number) – Negative Helicity (m2/s2)

sharppy.sharptab.winds.max_wind(prof, lower, upper, all=False)[source]¶

Finds the maximum wind speed of the layer given by lower and upper levels. In the event of the maximum wind speed occurring at multiple levels, the lowest level it occurs is returned by default.

Parameters

prof (profile object) – Profile Object
lower (number) – Bottom level of layer (m, AGL)
upper (number) – Top level of layer (m, AGL)
all (Boolean) – Switch to change the output to sorted wind levels or maximum level.

Returns

p (number, numpy array) – Pressure level (hPa) of max wind speed
maxu (number, numpy array) – Maximum Wind Speed U-component (kts)
maxv (number, numpy array) – Maximum Wind Speed V-component (kts)

sharppy.sharptab.winds.non_parcel_bunkers_motion(prof)[source]¶

Compute the Bunkers Storm Motion for a Right Moving Supercell

Parameters

prof (profile object) – Profile Object

Returns

rstu (number) – Right Storm Motion U-component (kts)
rstv (number) – Right Storm Motion V-component (kts)
lstu (number) – Left Storm Motion U-component (kts)
lstv (number) – Left Storm Motion V-component (kts)

sharppy.sharptab.winds.corfidi_mcs_motion(prof)[source]¶

Calculated the Meso-beta Elements (Corfidi) Vectors

Parameters

prof (profile object) – Profile Object

Returns

upu (number) – U-component of the upshear vector (kts)
upv (number) – V-component of the upshear vector (kts)
dnu (number) – U-component of the downshear vector (kts)
dnv (number) – V-component of the downshear vector (kts)

sharppy.sharptab.winds.mbe_vectors(prof)[source]¶

Thin wrapper around corfidi_mcs_motion()

Parameters

prof (profile object) – Profile Object

Returns

upu (number) – U-component of the upshear vector (kts)
upv (number) – V-component of the upshear vector (kts)
dnu (number) – U-component of the downshear vector (kts)
dnv (number) – V-component of the downshear vector (kts)

sharppy.sharptab.winds.non_parcel_bunkers_motion_experimental(prof)[source]¶

Compute the Bunkers Storm Motion for a Right Moving Supercell

Parameters

prof (profile object) – Profile Object

Returns

rstu (number) – Right Storm Motion U-component (kts)
rstv (number) – Right Storm Motion V-component (kts)
lstu (number) – Left Storm Motion U-component (kts)
lstv (number) – Left Storm Motion V-component (kts)

sharppy.sharptab.winds.critical_angle(prof, stu=0, stv=0)[source]¶

Calculates the critical angle (degrees) as specified by Esterheld and Giuliano (2008). If the critical angle is 90 degrees, this indicates that the lowest 500 meters of the storm is experiencing pure streamwise vorticity.

Parameters

prof (profile object) – Profile Object
stu (number (optional; default = 0)) – U-component of storm-motion (kts)
stv (number (optional; default = 0)) – V-component of storm-motion (kts)

Returns

angle – Critical Angle (degrees)

Return type

number

sharppy.sharptab package¶

Submodules¶

sharppy.sharptab.constants module¶

sharppy.sharptab.fire module¶

sharppy.sharptab.interp module¶

sharppy.sharptab.params module¶

sharppy.sharptab.prof_collection module¶

sharppy.sharptab.profile module¶

sharppy.sharptab.thermo module¶

sharppy.sharptab.utils module¶

sharppy.sharptab.watch_type module¶

sharppy.sharptab.winds module¶

Module contents¶