20010820: Wind Chill Calculation

>From: Daryl Herzmann <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200108210420.f7L4Kb118660

>Hello,
>       On the radio the other day, I heard that the way the NWS
>calculates Wind Chill will be changing this winter.  What is the status
>of this change with regards to how GEMPAK calculates Wind Chill?  Will a
>patch be available? Will seperate variables be maintained for the old and
>new method?
>
>Thanks,
>       Daryl
>


Daryl,

The WCEQ parameter is computed in $GEMPAK/source/gemlib/pr/prwceq.f using:

C* The following equation is used:                                      *
C*                                                                      *
C*      PR_WCEQ = 33.0 - ( (33.0 - TMPC) * WCI (SPED) / WCI (1.34) )    *
C*                                                                      *
C*              where: WCI ( V ) = ( 10.0 * SQRT ( V ) + 10.45 - V )    *
C*                                                                      *
C* From: R. Falconer, "Windchill, A Useful Wintertime Weather           *
C*                      Variable", Weatherwise, Dec 1968.               *

The reference is provided from Falconer. You can assess how this differs
from other versions of the computation.

I do not know whether NCEP will change/add any other heuristic calculations.


Steve Chiswell