[GEMPAK #NAT-847496]: GEMPAK - NARR Model Sounding Max Temp / Conv. Temp Bug

> Steve,
> 
> Thanks for your reply.  Clearly I misunderstood that Max Temp is a forecast 
> Max Temp and not simply the maximum temperature at the time of a sounding.  
> Also, I misinterpreted how NSHARP calculated the convective temperature.  I 
> didn't dig deep enough into the code and comments and should have done so 
> before contacting you.
> 
> Evan
> 

Evan,

No problems. Nsharp is one of those add on" programs so its documentation etc 
isn't
as well integrated with the rest of the package.

Steve Chiswell
Unidata User Support



> -----Original Message-----
> From: Unidata GEMPAK Support [mailto:address@hidden]
> Sent: Thursday, September 27, 2007 2:51 PM
> To: address@hidden
> Cc: address@hidden
> Subject: [GEMPAK #NAT-847496]: GEMPAK - NARR Model Sounding Max Temp / Conv. 
> Temp Bug
> 
> > Institution: Plymouth State University
> > Package Version: NSHARP 4.0
> > Operating System: Linux
> > Hardware Information: Dell Server
> > Inquiry: Hi,
> >
> > Just pointing out a possible bug.  When generating NARR model proximity 
> > (lat/lon) soundings in the latest version of NSHARP, it appears that Max 
> > Temp and Conv Temp values are flipped.
> >
> > Max Temp is actually Conv Temp and vice versa. The values are correct but 
> > flipped.
> >
> > Attached is a postscript example taken from 20030708_0900 at 43.64, -70.63.
> >
> > Evan Lowery
> >
> > --------
> > Plymouth State University
> > Applied Meteorology M.S. Program
> >
> >
> >
> 
> Evan,
> 
> The Max Temp being computed is:
> /*  Calculates a maximum temperature forecast based on       */
> /*  depth of mixing level and low level temperatures.        */
> 
> Looking at your postscript file, a miximg down of the air at the top
> opf the inversion dry adiabatically would result graphically of 26X which is
> close to the Max Temp of 84F shown in your plot.
> 
> 
> The Convective temperature is:
> /*  Computes convective temperature, assuming no change in   */
> /*  moisture profile.  Parcels are iteratively lifted until  */
> /*  only (mincinh) j/kg are left as a cap.  The first guess  */
> /*  is the observed surface temperature.                     */
> 
> The mincinh specified for this output is "-50 j/kg". Note that the dashed line
> shown in the plot is the default most unstable level, and not surface which
> can be specified using the PARCEL button on the page. Again, frlm ispection 
> of your plot,
> the value of 20C would be pretty close to the moist adiabat of most of the 
> atmosphere brought
> down to the surface, so that is ~68F. The value shown of 65F in your plot is 
> that which
> contains a cap of -50 j/kg, so again, based on what is shown in your plot, 
> the values
> seem to match.
> 
> My inperpretation is that with a convective temperature lower than the 
> theoretical max temp,
> you would expect cloudcover to begin after convetctive mixing begins which 
> would
> therefore be a counteractive force to the expected max tempBut, were you 
> expecting something
> different?.
> 
> Steve Chiswell
> Unidata User Support
> 
> Ticket Details
> ===================
> Ticket ID: NAT-847496
> Department: Support GEMPAK
> Priority: Normal
> Status: Closed
> 
> 
> 


Ticket Details
===================
Ticket ID: NAT-847496
Department: Support GEMPAK
Priority: Normal
Status: Closed