AREA FORECAST DISCUSSION

 
 FXUS65 KPIH 222059
 AFDPIH
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE POCATELLO ID
 200 PM MST SUN NOV 22 2009
 
 .SHORT TERM...TONIGHT THROUGH WEDNESDAY. LEADING EDGE OF UPPER 
 TROUGH WORKING THROUGH REGION EARLY THIS AFTERNOON WITH ASSOCIATED 
 PRECIPITATION BAND EXTENDING FROM REXBURG WSW THROUGH JACKPOT AND 
 MOVING AT A GOOD CLIP TO THE EAST. EXPECTATION IS THAT THIS BAND 
 WILL EXIT EAST INTO THE ERN HIGHLANDS BY LATE AFTERNOON/EARLY 
 EVENING WITH LINGERING SHOWERS AND BREEZY WEST-NW WINDS CONTINUING 
 OVER THE REGION AS UPPER TROUGH WORKS EAST INTO WYOMING OVERNIGHT. 
 HEAVY SNOWFALL HAS ALL BUT ENDED BEHIND THE MAIN PRECIP BAND AND 
 THUS HAVE CANCELLED THE WINTER STORM WARNING FOR SAWTOOTH MOUNTAINS 
 AND DROPPED THE ADVISORY FOR THE LOST RIVER REGION AND SOUTH CENTRAL 
 HIGHLANDS. UPPER RIDGE EXPANDS ACROSS REGION MONDAY AS A SECONDARY 
 SHORT-WAVE TOPS RIDGE AND SHEARS EAST THROUGH CANADA. THUS DRIER 
 CONDITIONS SHOULD PREVAIL MONDAY AND ON INTO WEDNESDAY AS RIDGE 
 DOMINATES. TEMPERATURES WILL BE SOMEWHAT TRICKY WITH CLEARING SKIES 
 ALLOWING OVERNIGHT LOWS THE NEXT COUPLE OF NIGHTS TO DROP SHARPLY 
 WHILE DAYTIME HIGHS STRUGGLE TO BURN THROUGH THE COLD AIR TRAPPED IN 
 THE VALLEYS. THUS AM TRYING NOT TO STRAY TOO FAR FROM GUIDANCE 
 THROUGH THE PERIOD. HUSTON  
 
 .LONG TERM...WEDNESDAY NIGHT THROUGH NEXT SUNDAY.  STRONG UPPER 
 LEVEL RIDGING STARTS THIS PERIOD...BUT BREAKS DOWN AT THE 36 HOUR 
 POINT.  HOW MUCH IT BREAKS DOWN IS THE MAIN FORECAST PROBLEM.  GFS 
 KEEPS A DRIER FORECAST WITH THE STORM TRACK FARTHER NORTH...BUT MORE 
 STABLE ECMWF KEEPS A STEADY STREAM OF SHORTWAVES CLIPPING THE 
 NORTHERN HALF OF THE FORECAST AREA.  HAVE GONE WITH THE 
 NCEP-PREFERRED ECMWF AND THUS HAVE HIGHER THAN GFS POPS AND COLDER 
 TEMPERATURES FOR AFTERNOON HIGHS.  DO NOT SEE ANY SIGNIFICANT WIND 
 EVENTS DURING THIS PERIOD.  THE FRI/FRI NIGHT STORM IS THE HEAVIEST 
 PRECIPITATION MAKER...AND MAY NEED SOME LOW-LEVEL ADVISORY 
 HIGHLIGHTS EVENTUALLY.  MESSICK 
 &&
 
 .AVIATION...FRONT IS PASSING THROUGH THIS AFTERNOON WITH ISOLATED TO 
 WIDELY SCATTERED LIGHT SHOWERS BEHIND.  MAIN PROBLEMS WILL BE THE 
 WIND SHIFT AND THE RISK OF FOG AND STRATUS IN THE MORNING.  WITH 
 STRONG WIND CONTINUING ALOFT...DO NOT EXPECT FOG...BUT VERY LIKELY 
 CEILING WILL BE AFFECTED...MAINLY IN THE SNAKE RIVER PLAIN 
 AIRPORTS.  KSUN APPEARS TO BE FAIRLY DRY ONCE THEY RE-OPEN MON 
 MORNING.  DRYING TREND THROUGH THU...SO ONLY THREAT IS MORNING 
 STRATUS AND FOG.  MESSICK
 &&
 
 .PIH WATCHES/WARNINGS/ADVISORIES...
 WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR IDZ019-023-025.
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