945 
FXUS63 KDMX 171000
AFDDSM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
357 AM CST WED JAN 16 2001

FORECAST CHALLENGE FOR TODAY IS CLOUD TRENDS AND TEMPERATURES.  FOR 
THURSDAY AND THURSDAY NIGHT THE CHALLENGE BECOMES SNOW CHANCES.  

SATELLITE TRENDS SHOWING STRATUS FIELD OVER MN SHIFTING TO THE SE 
AND SHRINKING CREATING A QUESTION AS TO THE EXTENT OF CLOUD COVER 
OVER THE CWA.  SRN STRAM SYSTEM SHOULD AT LEAST SPREAD ID CLOUDS 
OVER CEN IA SO I KEPT THE VARIABLE CLOUDINESS FORECAST GOING.  
NEUTRAL TEMP ADVECTION SHOULD SPELL HIGHS MUCH LIKE WE HAVE BEEN 
SEEING SO WILL FORECAST MID 20S AGAIN WHICH MOS HAS WELL 
HANDLED.

THE BIGGER PROBLEM IS THE POP FORECAST FOR THURSDAY.  ETA AND NGM 
KEEP THE VORT MAX NORTH OF IA AND SHEAR IT OUT THUS HAVING LITTLE 
IMPACT OVER THE STATE BUT THE AVN HAS A DIFFERENT SOLUTION.  IT 
MOVES THE FIRST WAVE BY THURSDAY AND DEVELOPS A CLOSED LOW DIGGING 
INTO OK LATE THURSDAY THROUGH SATURDAY.  NERLY FLOW DOMINATES AND A 
VORT MAX MOVES ACROSS IA THURSDAY NIGHT AND FRIDAY INTENSIFYING THE 
LOW.  SO FAR THIS IS THE ODD MODEL OUT SO WHILE THIS BEARS WATCHING 
I WILL LIKELY GO WITH A BLEND OF THE ETA/NGM.  THERE IS SOME DECENT 
WAA WHICH DEVELOPS OVER IA TONIGHT THROUGH THURSDAY WHICH SHOULD ACT 
TO KEEP AT LEAST MID CLOUDS OVER US THROUGH THURSDAY.  850 CAA IS 
PRETTY DECENT FOR THURSDAY NIGHT AND FRIDAY BUT CLOUDS WL LIKELY 
TEMPER WHAT GUIDANCE IS SUGGESTING.

AS FOR THE EXTENDED...ALL THE MODELS RESOLVE THE SCENARIO BY MOVING 
THE GREAT LAKES TROUGH EAST FRIDAY WITH RIDGING OCCURRING OVER IOWA 
SATURDAY SO I TOOK OUT CHANCE PRECIP FOR SATURDAY BUT LEFT THE REST 
OF THE EFP ALONE.

.DSM...NONE

FAB