[Support #QIA-399358]: Metpy python skew-t

Greetings,

I think one problem here is that to properly apply the virtual temperature 
correction, you don't just use Tv as your starting point for parcel ascent, but 
you need to correct *all* of the temperatures (since what you're doing is 
correcting temperature to better represent the density of the air including 
moisture). Here's some code that seemed to work for me;

    import metpy.calc as mpcalc
    from metpy.cbook import get_test_data
    from metpy.units import units
    import pandas as pd

    # Read from our test dataset
    col_names = ['pressure', 'height', 'temperature', 'dewpoint', 'direction', 
'speed']
    df = pd.read_fwf(get_test_data('may22_sounding.txt', as_file_obj=False),
                     skiprows=5, usecols=[0, 1, 2, 3, 6, 7], names=col_names)

    # Drop any rows with all NaN values for T, Td, winds and assign units
    df = df.dropna(subset=('temperature', 'dewpoint', 'direction', 'speed'), 
how='all'
                   ).reset_index(drop=True)
    p = df['pressure'].values * units.hPa
    t = df['temperature'].values * units.degC
    td = df['dewpoint'].values * units.degC

    # Calculate the parcel profile including the LCL--and get new pressure, 
temperature,
    # and dewpoint that include values interpolated at the LCL
    p, t, td, prof_t = mpcalc.parcel_profile_with_lcl(p, t, td)

    # Calculate the water vaport mixing ratio from dewpoint
    mv = mpcalc.mixing_ratio(mpcalc.saturation_vapor_pressure(td), p)

    # Calculate the virtual temperature for the atmospheric temperature profile
    # and for the parcel's profile
    tv = mpcalc.virtual_temperature(t, mv)
    prof_tv = mpcalc.virtual_temperature(prof_t, mv)

    # Calculate cape/cin using the virtual temperature for *both* temperatures
    mpcalc.cape_cin(p, tv, td, prof_tv)

Hope that helps,

Ryan

> Hello,
> 
> The Tv prints out one number as it should but when I do this:
> 
> # Virtual temperature
> parcel_prof_virtual = mpcalc.parcel_profile(p, Tv, Td[0]).to('degC')
> 
> # Calculate CAPEV / CINSV Not working properly
> # CAPEV, CINSV = mpcalc.capev_cinv(p, Tv, Td[0], parcel_prof_virtual, 
> which_lfc='bottom', which_el='top')
> 
> It throws an error for parcel_prof_virtual which also throws an error for the 
> next line.


Ticket Details
===================
Ticket ID: QIA-399358
Department: Support Python
Priority: Normal
Status: Closed
===================
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