Weather Service Report


983 
FXUS65 KPIH 180148
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
650 PM MST WED DEC 17 2014

.UPDATE...SECOND UPDATE TO INCREASE THE CLOUD COVER SPREADING IN 
FROM THE WEST. SEE PREVIOUS DISCUSSION BELOW. HUSTON

UPDATED TO INCLUDE POTENTIAL FOR AT LEAST PATCHY DENSE FREEZING FOG 
TONIGHT IN THE BLACKFOOT...IDAHO FALLS AND REXBURG AREAS. TONIGHT IS 
NOT QUITE THE SITUATION WE HAD YESTERDAY WHERE MIXED RAIN AND SNOW 
FELL IN THE EVENING HOURS WHERE TEMPERATURES WERE BEGINNING TO FALL. 
THAT WAS ALSO FOLLOWED BY SOME CLEARING OF CLOUD COVER TOWARDS 
MORNING. TONIGHT SOME STATUS IS EXPECTED TO REDEVELOP ALONG WITH 
SOME AREAS THAT COULD BE SHORT ON CLOUD COVER. IDAHO FALLS WAS THE 
LAST AREA TO CLEAR TODAY AND JUST MIGHT BE THE BEST AND FIRST 
LOCATION FOR FOG TO RETURN TONIGHT. IF IT TURNS INTO A STATUS DECK 
100 TO 200 FEET OFF THE GROUND...THAT COULD KEEP THE VISIBILITY FROM 
DROPPING BELOW A QUARTER MILE AGAIN. HAVE TO WATCH THIS. RS
&&

.PREV DISCUSSION... /ISSUED 209 PM MST WED DEC 17 2014/ 

SHORT TERM...A TRANSITORY HIGH PRESSURE RIDGE WILL BE OVER
SOUTHEAST IDAHO TONIGHT. THERE IS STILL A SLIGHT CHANCE OF LIGHT
SNOW IN THE EASTERN HIGHLANDS AND THE WEST SLOPES OF THE CENTRAL
MOUNTAINS INCLUDING THE STANLEY AREA. ANY ACCUMULATION SHOULD BE
VERY LIGHT. DAY TIME THURSDAY THE CHANCE OF SNOW INCREASES WITH
THE PASSAGE OF A MINOR DISTURBANCE. SNOW SHOULD AGAIN BE LIMITED
TO THE MOUNTAINS WITH LITTLE ACCUMULATION ANTICIPATED. FAST
WESTERLY WINDS OFF THE PACIFIC WILL BRING A STRONGER DISTURBANCE
THROUGH FRIDAY AND FRIDAY NIGHT. THIS ONE COULD BRING 1 TO 4
INCHES IN THE MOUNTAINS AND UP TO 1 INCH IN THE SNAKE PLAIN. VERY
MOIST WESTERLY WINDS LOOKS TO BE DEVELOPING FOR THIS WEEKEND AND
BEGINNING SATURDAY THIS COULD BRING POTENTIAL FOR SOME SIGNIFICANT
SNOW AMOUNTS TO THE WESTERLY EXPOSED HIGHER ELEVATIONS. THIS MAY
SOUND GOOD FOR SKIING...BUT BE SURE TO KEEP CURRENT ON THE WEATHER
AS THIS COULD TURN HAZARDOUS WITH SOME STRONG WINDS. RS

LONG TERM...SATURDAY NIGHT THROUGH THURSDAY. ACTIVE WEATHER WILL 
CONTINUE AS WE HEAD INTO EARLY NEXT WEEK. MOISTURE TRANSPORT REMAIN 
STRONG AS ZONAL FLOW SETS UP WITH THE UPPER JET DROPPING INTO 
CENTRAL IDAHO. STRONG ATMOSPHERIC RIVER SIGNAL FROM THE GFS ARRIVING 
IN SOUTHEAST IDAHO BY SUNDAY MORNING WITH MOIST CONDITIONS 
CONTINUING THROUGH MONDAY NIGHT. SNOW LEVELS LIFTING FROM 4500 FT 
SUNDAY MORNING TO 7500 FT BY MONDAY MORNING AS WARM AIR MAKES ITS 
WAY INTO THE REGION. MODELS ARE PRODUCING AROUND 12 TO 18 INCHES OF 
SNOWFALL OVER THE SAWTOOTH RANGE IN THE CENTRAL MOUNTAINS...AND 
ABOUT THE SAME OVER THE EASTERN HIGHLANDS AROUND 
DRIGGS/PALISADES...AND ABOUT A FOOT OF NEW SNOWFALL IN THE NORTHERN 
WASATCH RANGE. GFS SUPPORTING A STRONGER BOUNDARY LAYER FLOW SUNDAY 
NIGHT AND MONDAY THAN THE ECMWF AND SUGGEST BETTER CHANCES OF 
BLOWING SNOW OVER THE MOUNTAIN PASSES. ECMWF AND GFS PARALLEL 
DEVELOP UPPER LOW OVER SOUTHEAST IDAHO ON CHRISTMAS DAY. 00Z RUNS 
SHOWED LESS AMPLITUDE ON THE WAVE COMING OUT OF THE GULF OF ALASKA. 
YESTERDAYS 12Z ECMWF RUN ALSO SHOWED AN UPPER LOW OVER THE REGION. 
STILL TOO FAR OUT TO TELL IF THIS WILL BE A SIGNIFICANT EVENT. A 
CUTOFF LOW IN THE RIGHT PLACE COULD MAKE FOR A VERY WHITE CHRISTMAS. 
HINSBERGER 

AVIATION...DENSE FOG LINGERING OVER KIDA AT START OF TAF PERIOD. 
EXPECT THIS TO BURN OFF FAIRLY QUICKLY HEADING INTO THE EARLY 
AFTERNOON HOURS...BUT BOTH KPIH AND KIDA SHOULD BE HEADING TOWARD 
LIFR CONDITIONS AGAIN TONIGHT. THIS IS SUPPORTED BY FORECAST 
SOUNDINGS AND MOS GUIDANCE. KBYI SHOULD SEE A PERIOD OF MVFR 
CONDITIONS OVERNIGHT. GUIDANCE APPEARS TO FAVOR PERSISTENCE AS THIS 
IS WHAT OCCURRED LAST NIGHT. FINALLY AT KSUN...THE DIURNAL UP-VALLEY 
WINDS THIS AFTERNOON BEAR WATCHING AS SOME STRATUS MAY ADVECT UP 
THAT WAY FROM THE SNAKE PLAIN. HOLDING TO A SCATTERED DECK FOR NOW 
DURING THE AFTERNOON HOURS. HINSBERGER
&&

.PIH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$








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