365
FXUS65 KPIH 202131
AFDPIH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
228 PM MST FRI NOV 20 2009
SHORT TERM
A STRONG PACIFIC SYSTEM IS PUSHING INLAND NOW.
CURRENTLY WE HAVE STRONG SOUTHERLY WINDS ACROSS THE AREA. RIDGE-TOPS
IN THE SOUTH CENTRAL HIGHLAND MOUNTAINS ARE RECEIVING GUSTS OF JUST
UNDER 50 MPH WITH SEVERAL GAP AREAS RECEIVING GUSTS JUST ABOVE 40
MPH. EXPECT THE HIGH WINDS TO CONTINUE THIS AFTERNOON INTO THE
EVENING. EXPECT SUSTAIN WINDS OF 25 TO 30 MPH WITH GUSTS NEAR 50 MPH
AT RIDGE TOPS...GAPS AND DOWNSLOPE AREAS. THESE STRONG WINDS WILL
OCCUR MAINLY IN SOUTH CENTRAL AND CARIBOU HIGHLANDS AND ADJACENT
AREAS IN THE LOWER SNAKE RIVER PLAIN. A WIND ADVISORY IS IN EFFECT
FOR ZONES 21...22 AND 23 PRIMARILY FOR HIGHER ELEVATIONS...GAPS AND
DOWNSLOPE AREAS FROM 2 PM TO 11 PM TODAY. RIDGE TOPS ACROSS ALL
SOUTHEAST IDAHO WILL RECEIVE STRONG WINDS. A COLD FRONT WILL BEGIN
PUSHING THROUGH TONIGHT AFTER MIDNIGHT. SNOW SHOWERS WILL BEGIN IN
THE WESTERN CENTRAL MOUNTAINS AND PUSH EASTWARD OVERNIGHT INTO EARLY
MORNING. WITH GOOD COLD AIR BEHIND THE FRONT...THE SNOW LEVELS WILL
DROP OVERNIGHT INTO EARLY MORNING. SNOW AMOUNTS OF 3 TO 6 INCHES ARE
POSSIBLE IN THE CENTRAL MOUNTAINS...UPPER SNAKE HIGHLANDS AND
EASTERN HIGHLANDS WITH HIGHER AMOUNTS ALONG RIDGE TOPS. MODELS ARE
INDICATING THE POSSIBILITY OF A CONVERGENCE EVENT SETTING UP ALONG
THE EASTERN UPPER SNAKE RIVER PLAIN EARLY AFTERNOON WITH THE
POSSIBILITY OF 2 TO 4 INCHES OF SNOW. VERY LITTLE ACCUMULATION IS
EXPECTED IN THE LOWER SNAKE RIVER PLAIN. SATURDAY AFTERNOON STRONG
WINDS ARE AGAIN EXPECTED IN THE LOWER AS WELL AS UPPER SNAKE RIVER
PLAIN BEHIND THE FRONT. MODELS ARE CURRENTLY INDICATING WINDS RIGHT
AT THE LOWER END OF A WIND ADVISORY LATE SATURDAY AFTERNOON INTO
EARLY SATURDAY EVENING. WYATT
EXPECT BRIEF RIDGING SATURDAY NIGHT BEFORE THE NEXT STRONG PACIFIC
SYSTEM BEGINS TO IMPACT THE WESTERN CENTRAL MOUNTAINS MID TO LATE
SUNDAY MORNING. THE MODELS HAVE PUSHED THIS BACK SEVERAL HOURS
FROM PREVIOUS RUNS. THIS WILL BE A POTENT SYSTEM AS WELL. THIS
SYSTEM WILL HAVE STRONG WESTERLY WINDS BUT NOT AS STRONG AS
FRIDAY NIGHT'S SOUTHERLY WINDS. THIS SYSTEM HAS THE POTENTIAL TO
BRING MORE SNOW WITH 4 TO 8 INCHES POSSIBLE IN THE CENTRAL AND
EASTERN HIGHLAND MOUNTAINS WITH HIGHER AMOUNTS AT RIDGE TOPS. IF
MODEL RUNS CONTINUE TO BE CONSISTENT EXPECT A WINTER ADVISORY TO
BE ISSUED. SNOW ACCUMULATION ACROSS SOUTHEAST IDAHO LOOKS POSSIBLE
FOR THIS SYSTEM AS WELL. THE SNAKE RIVER PLAIN COULD RECEIVE 1 TO
3 INCHES OF SNOW.
LONG TERM
GFS GUIDANCE HAS RETURNED TO MATCHING THE LATELY MORE
CONSISTENT ECMWF AND THUS HAVE BEEN USING GFS GUIDANCE FOR
TEMPERATURES. PROGRESSIVE PATTERN TAKES A BREAK DURING THE UPCOMING
THANKSGIVING HOLIDAY TO MAKE IT THE WARMEST DAY OF THE WEEK. RIDGE
THAT DEVELOPS ON WED-THU BEGINS ITS BREAKDOWN AS EARLY AS FRI...BUT
MORE LIKELY FRI NIGHT. EXPECT CLEAR AND VERY COLD OVERNIGHT DURING
THAT TIME...BUT TEMPERATURES PUSHING WARMING THAN NORMAL FOR
AFTERNOON HIGHS. A STORM WRAPPING UP MON IS THE ONLY SIGNIFICANT
PRECIPITATION...THE OTHER STORMS MOSTLY CLOUDS AND ONLY SLIGHT
CHANCES. MESSICK
AVIATION
WIND HAD JUST STARTED TO GUST AT THE SNAKE RIVER
AIRPORTS. WIND APPEARS TO CEASE GUSTING FOR THE EARLY EVENING.
KBYI IS STRUGGLING WITH THIS RIGHT NOW. WIND SPEED INCREASES AGAIN
THE FRONT APPROACHES. EXPECT FRONT WITH SOME LIGHT PRECIPITATION
FROM 21/09Z TO 21/15Z. GUSTY WIND SHOULD KEEP TEMPERATURES UP AND
THUS EXPECT MOSTLY RAIN AT KBYI...BUT COULD SEE SNOW AT KIDA AND
KPIH. SNOW AT KSUN SHOULD BE ENDING JUST AS THE AIRPORT OPENS...BUT
TRENDS HAVE BEEN TO SLOW THE APPROACH AND IT MAY END UP WITH A SHUT
DOWN AIRPORT DURING THE MORNING HOURS. MESSICK
PIH WATCHES/WARNINGS/ADVISORIES
WIND ADVISORY UNTIL 11 PM MST THIS EVENING FOR IDZ021>023.
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