FXUS65 KPIH 061031
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
331 AM MST SUN DEC 6 2009

.SHORT TERM...TODAY THROUGH TUE NIGHT. UPPER LEVEL TROUGHING WILL
SLOWLY EXIT THE REGION...LEAVING NORTHERLY FLOW WITH UPPER LEVEL
RIDGING STAYING IN THE PACIFIC. ARCTIC AIR FROM CENTRAL CANADA
WILL CONTINUE TO STREAM INTO THE FORECAST AREA. TEMPERATURES WILL
STRUGGLE TO REACH THE 20S EVEN TODAY...BUT EVEN MORE SO MON. A
SHIFT TO SOUTHERLY FLOW DEVELOPING MON AFTERNOON WILL MODERATE
THIS SOME. WITH MODERATE WIND TONIGHT COMBINING WITH EXTREME COLD
AIR...HAVE ISSUED WIND CHILL WATCH FOR TONIGHT AND MON MORNING.
LIGHT PRECIPITATION CONTINUES TO BE A THREAT MAINLY IN MOUNTAIN
LOCATIONS SOUTH OF THE SNAKE RIVER WHERE THE NORTHERLY WIND IS
PRODUCING UPSLOPE FLOW ENHANCEMENTS TO PRECIPITATION. VERY LITTLE
MOISTURE TO WORK WITH AND DO NOT EXPECT ANYTHING MORE THAN LIGHT
SNOW. UPPER LEVEL DYNAMICS FOR PRECIPITATION PRODUCTION HAVE SLID
TO THE SOUTH AND ARE EXPECTED TO RESIDE OVER SOUTHERN UTAH FOR
THIS PERIOD...LEAVING EASTERN IDAHO IN A DRY SLOT.  MESSICK

.LONG TERM...WEDNESDAY THROUGH SUNDAY. MODELS ARE IN GOOD AGREEMENT 
THROUGHOUT THE EXTENDED RANGE WITH GFS...GFS ENSEMBLES...AND ECMWF 
VERY CLOSELY REPRESENTING SYNOPTIC FEATURES. DEEP TROUGH OVER 
CENTRAL CONUS WITH NORTHERLY FLOW OVER IDAHO TRANSITIONS TO A LARGE 
FLAT TROUGH OVER ENTIRE CONUS BY THE END OF THE PERIOD. HAVE KEPT 
MAINLY CHANCE POPS /SLIGHTLY ABOVE CLIMO/ OVER FCST AREA THROUGHOUT 
EXTENDED RANGE. WITH COLD NORTHERLY FLOW EXPECT PRECIP TO BE LARGELY 
LOW QPF SHOWERS. BY NEXT WEEKEND UNDER ZONAL FLOW CHANCES INCREASE 
FOR HIGHER QPF EVENTS. SOME DETAIL DIFFERENCES BETWEEN GFS AND ECMWF 
REGARDING SPREAD OF PRECIP BUT OVERALL PATTERN SHOULD REMAIN 
UNSETTLED. FORECAST TEMPS CONTINUE TO BE CLOSE TO GUIDANCE AND BELOW 
NORMAL FOR EARLY DECEMBER. DMH

&&

.AVIATION...A MIX OF VFR AND MVFR WILL CONTINUE THROUGH MUCH OF THE 
DAY FOR MOST OF EASTERN IDAHO. A STRONG UPPER LOW REMAINS IN PLACE 
WITH BRISK NORTHERLY WINDS THROUGH MUCH OF THE REGION. THE GREATEST 
CHANCE FOR SNOW SHOWERS WILL REMAIN CONFINED TO UPSLOPE AREAS 
ESPECIALLY IN THE SOUTHEAST CORNER OF THE STATE THROUGH TONIGHT BUT NOT 
OUT OF THE QUESTION ELSEWHERE. CEILINGS AND VISIBILITIES SHOULD DROP 
TO IFR CONDITIONS WITH THE SNOW. DMH

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
WIND CHILL WATCH FROM THIS AFTERNOON THROUGH MONDAY MORNING FOR 
IDZ017-019>021-023-025-031-032.

&&

$$