FXUS65 KPIH 240820
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO IDAHO
130 AM MST WED NOV 24 2004

.DISCUSSION...SHORT TERM...TODAY THROUGH FRIDAY NIGHT...THE LATEST 
SATELLITE IMAGERY SHOWS WARM AIR ADVECTION CLOUDS/PRECIP MOVING 
TOWARD THE CENTRAL MTS.  THIS WILL OVERSPREAD THE ENTIRE FORECAST 
AREA EARLY THIS MORNING AS STRONG LOW LEVEL WARM AIR ADVECTION 
(850-650MB) ENVELOPS THE AREA WHICH LASTS FOR ABOUT 36HRS.  TIME 
HEIGHT/X-SECTIONS CONTINUE TO SHOW SEVERAL OMEGA MAXES ASSOCIATED 
WITH THE STRONG THERMAL ADVECTION AND THIS WILL LEAD TO AN 
INCREASINGLY WET PERIOD TODAY INTO THANKSGIVING.  SNOW WILL DEVELOP 
DURING THE MORNING HOURS OVER THE CENTRAL MTS...THEN EXTEND EAST 
INTO THE UPPER SNAKE/CARIBOU HIGHLANDS DURING THE AFT/EVE. WOULD 
ANTICIPATE 2 TO 6 INCHES THROUGH MIDNIGHT TONIGHT FOR THE CENTRAL 
MTS AND UPPER SNAKE/CARIBOU HIGHLANDS.  FOR THE SNAKE RIVER 
PLAIN...A SOLID STRATUS DECK WITH MODELS SHOWING 20 TO 30 POPS 
ACROSS THE AREA TODAY AND THIS IS LOOKS ACCEPTABLE...THUS CHANCE OF 
POPS WILL SUFFICE.  FOR THE LOWER SNAKE PLAIN...ANY PRECIP WOULD BE 
IN THE FORM OF LIGHT SNOW THROUGH EARLY AFTERNOON...THEN CHANGE TO A 
RAIN/SNOW MIX BEFORE CHANGING TO RAIN BY LATE THIS AFTERNOON.  THIS 
IN RESPONSE TO SOUTHWEST SFC WINDS OF 15 TO 20MPH DEVELOPING AFTER 
18Z WHICH WILL HELP SCOUR OUT THE COLD AIR AND ALLOW TEMPS TO RISE 
INTO THE UPPER 30S/LOWER 40S.  BREEZY SW WINDS WILL KEEP OVERNIGHT 
LOWS IN THE MID AND UPPER 30S ACROSS THE LOWER SNAKE PLAIN.  NORTH 
OF POKY...INTO IDAHO FALLS AND POINTS NORTH...IT WILL BE HARDER TO 
SCOUR OUT THE COLDER AIR AND ANY PRECIP TODAY WILL MAINLY BE IN THE 
FORM OF SNOW AND THEN POSSIBLY A SNOW/RAIN MIX TOWARD EVENING AND 
OVERNIGHT.  850 WET BULB TEMPS SHOW SNOW LEVELS GRADUALLY RISING TO 
5500FT BY THIS EVENING...THEN TO 6000FT OVERNIGHT...AND FINALLY WILL 
PEAK OUT BETWEEN 6000FT-6500FT ON THURSDAY.  MOST WIDESPREAD PRECIP 
WILL COME ON THANKSGIVING DAY BETWEEN 18Z THU-06Z FRI.  STRONG JET 
DYNAMICS COMING TOGETHER AS THE SFC FRONT PASSES THROUGH THE 
FORECAST AREA (FROM NW TO SE) BETWEEN 00Z-06Z FRI.  TOTAL SNOW 
ACCUMULATIONS ON ALL MODELS SHOW A TOTAL OF 8 TO 13 INCHES OVER A 
GOOD PORTION OF THE UPPER SNAKE AND CARIBOU HIGHLANDS (ZONES 19/23) 
BY 00Z FRI...AND OVER PORTIONS OF CUSTER COUNTY AROUND STANLEY (ZONE 
18). PAST FEW RUNS HAVE BEEN CONSISTENT WITH THIS TREND AND WILL BE 
ISSUING A WINTER STORM WATCH FOR ZONES 18/19/23 BEGINNING 06Z THU TO 
06Z FRI.  WILL LET DAY SHIFT DECIDE IF A HEAVY SNOW WARNING SHOULD 
BE ISSUED LATER IN THE PERIOD. MUCH COLDER WEATHER FOR 
FRIDAY...HIGHS NEAR 30 WITH SCATTERED SNOWSHOWERS.   

SIMOSKO

...EXTENDED FORECAST...SAT THROUGH TUE.  MOIST NW FLOW ALOFT 
CONTINUES DAYS 4-5 WITH MODELS DIFFERING ON EXTENT OF THE POLAR JET 
ENERGY THAT CARVES OUT AN U/L TROUGH OVER THE GREAT BASIN BY LATE 
SUN.  GFSLR IS THE MOST "CUT OFF" AND COLDER OF ALL THE MODELS WHILE 
THE EC/UK ARE MORE OPEN AND PROGRESSIVE.  AS PER PMDEPD AND SEVERAL 
NOTED MODEL CONSISTENCY ISSUES WILL GO WITH THE SLIGHTLY MORE OPEN 
SOLUTION WHICH WOULD TEND TO BUILD IN AN UPSTREAM RIDGE FASTER OVER 
EAST ID BY DAY 5.  THUS AGREE WITH SCHC POPS OVER MOST ZONES DAYS 
4-5 WITH ONLY A FEW SNOW SHOWERS ACROSS THE HIGHER TERRAIN AFTER DAY 
5 WITH DRY ELSEWHERE.  NO SIGNIFICANT CHANGES TO GRIDS.

&&

.PIH WATCHES/WARNING/ADVISORIES...A WINTER STORM WATCH HAS BEEN 
ISSUED FOR ZONES 18/19/23.  PLEASE REFER TO BULLETIN WSWPIH FOR 
ADDITIONAL DETAILS.  
&&

$$