Re: [idvusers] Plotting Surface Wind Chill & Heat Index Values

• To: Brendon Hoch <bhoch@xxxxxxxxxxxx>
• Subject: Re: [idvusers] Plotting Surface Wind Chill & Heat Index Values
• From: Julien Chastang <chastang@xxxxxxxx>
• Date: Tue, 28 Feb 2017 19:25:39 -0700

Hi Brendon,

The Layout Model Editor can take a (simple?) formula in the Value parameter
field. However, I was never able to get this to work for wind chill.

However, I think there are still a couple of ways you could do this. Define
a
Wind Chill formula
(
http://mailman.unidata.ucar.edu/mailing_lists/archives/idvusers/2016/msg00022.html).
Then
you can take the analysis grid of a model and apply the wind chill formula
to
that grid. You could even plot them as Value Plots to make them vaguely look
like a station plot. You could also apply that same wind chill formula to
the
the Barnes analysis Gridded Fields coming from the surface observations.
That's
another option.

A similar reasoning would apply for the heat index, the formula for which
you
would have to define in a similar manner as the wind chill. Someone has done
this in Python so migrating this do Jython should be doable:

https://github.com/gregnau/heat-index-calc/blob/master/heat-index-calc.py

The main bugaboo is the heat index equation works in Fahrenheit so you need
to
pay attention to the units as you have to for all formulas.

Hope that helps.

-Julien


On Tue, Feb 28, 2017 at 7:11 AM, Brendon Hoch <bhoch@xxxxxxxxxxxx> wrote:

> Hello,
>
> IDV works great if you want to plot real time surface temperatures or
> dewpoint temperature point values from METAR data.  However, there does not
> seem to be a straightforward way to plot heat index or wind chill. Has
> anyone else figured out how to do this?  Is this something that needs to
> get put in to IDV by Unidata developers?
>
> PS: Gempak can do this easily just by changing SFPARM from TMPF to WCHT or
> HEAT
>
> Thanks,
> Brendon
> --
> Brendon Hoch, M.S.
> MSC 48, Boyd Science Center 319
> Plymouth State University
> Plymouth, NH 03264
> (603)535-2818 Fax: (603)535-2723
>
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-- 
Julien Chastang
Scientific Software Developer
Unidata-UCAR

• References:
  • [idvusers] Plotting Surface Wind Chill & Heat Index Values
    • From: Brendon Hoch