Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 182010
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
110 PM MST TUE NOV 18 2014

.SHORT TERM...TONIGHT THROUGH FRIDAY.
INVERSIONS STILL PRESENT UNDER HIGH PRESSURE AT THE SURFACE.
SHOULD HAVE ANOTHER VERY COLD NIGHT OVERNIGHT WITH SINGLE DIGITS
ABOVE AND BELOW ZERO AGAIN EXPECTED. UPPER LEVEL RIDGE MOVES EAST
TOMORROW AS WEAK PACIFIC SYSTEM BEGINS TO SPREAD MID AND HIGH
LEVEL CLOUDS INTO SOUTHEAST IDAHO. COULD SEE SOME LIGHT SNOW
THURSDAY INTO FRIDAY WITH THIS FIRST SYSTEM FOLLOWED BY ANOTHER
WEAK SYSTEM ON FRIDAY. SOME MOUNTAIN LOCATIONS MAY SEE AROUND AN
INCH OF SNOW THROUGH FRIDAY. SHOULD SEE A GRADUAL WARMING TREND IN
THE SHORT TERM WITH HIGHS REACHING THE MID TO UPPER 30S BY FRIDAY
CLOSE TO SEASONAL NORMALS. LOW TEMPERATURES SHOULD ALSO RISE AS
WELL THURSDAY AND FRIDAY MORNINGS. WINDS WILL REMAIN LIGHT THROUGH
FRIDAY.
GK

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY. SATURDAY LOOKS TO BE WET
AND WINDY ACROSS EASTERN IDAHO. THE LEADING OF RAIN AND SNOW ARRIVES
IN FAR WESTERN AREAS BEFORE SUNRISE AND SPREADS ACROSS THE ENTIRE
REGION DURING THE DAY. THE QUESTION RIGHT NOW WILL BE SNOW LEVELS
AND ANY FREEZING RAIN THREAT ACROSS THE SNAKE PLAIN AND SOUTHERN
HIGHLAND VALLEYS. THERE IS A STRONGER PUSH OF WARM AIR THIS TIME TO
BATTLE ANY COLD AIR TRAPPED IN THE VALLEYS WITH THIS WEEK`S
INVERSION CONDITIONS. BASED OFF SOUNDINGS...THE PRELIMINARY FORECAST
WOULD BE A QUICK CHANGE TO RAIN FOR THE SOUTHERN HALF OF THE MAGIC
VALLEY AND THE VALLEYS OF CASSIA COUNTY AND NO FREEZING RAIN. FOR
THE LOWER SNAKE PLAIN AND SOUTH INTO PLACES LIKE THE MARSH
VALLEY...ARBON VALLEY AND PRESTON...WE MAY SEE A THREAT OF LIGHT
FREEZING RAIN FOR A FEW HOURS BEFORE LIKELY SWITCHING TO ALL RAIN AT
THE VALLEY FLOORS LATER IN THE DAY. SNOW LEVELS PEAK AT 5000-5500
FOR THE EASTERN HALF AND 5500-6500FT OUT WEST. THIS WILL LIKELY
CHANGE AS WE GET A BETTER HANDLE ON ANY COLD AIR TRAPPED AT LOWER
ELEVATIONS. WINDS WILL BE HOWLING IT APPEARS WITH THIS STORM...WHICH
WILL HEIGHTEN IMPACTS WITH THIS PUSH ALTHOUGH IT WILL ONLY BE ABOUT
18-24 HOURS LONG. WINDS AT 8000-10000FT ACCORDING TO THE MODELS WILL
BE 40+KTS...WITH LIGHTER BUT STILL BREEZY CONDITIONS BELOW THAT.
THAT MEANS BLOWING/DRIFTING SNOW FOR SURE IN THE HIGHER ELEVATIONS.
IN THE VALLEYS WHERE SNOW MAY END UP WETTER...SOME BLOWING IS STILL
EXPECTED BUT POTENTIALLY NOT AS DRASTIC. SOUTHERLY WINDS ALONG/SOUTH
OF THE WARM FRONT MAY HELP REDUCE PRECIPITATION AMOUNTS ALONG THE
84/86 CORRIDOR...BUT IT WILL BE A BATTLE BETWEEN THAT AND INTENSITY
OF RAIN/SNOW/FREEZING RAIN. ALL AND ALL...SATURDAY WILL LIKELY END
UP A POOR DAY TO BE OUT AND ABOUT INCLUDING THOSE HEADING OUT EXTRA
EARLY FOR THANKSGIVING.

FOR SUNDAY AND BEYOND...THE FORECAST GETS A LITTLE LESS CERTAIN.
HIGH PRESSURE BUILDS ALONG THE COAST AND TRIES TO SHIFT EASTWARD
HEADING INTO NEXT WEEK. WHEN COMPARING THE MODELS AND ENSEMBLES...IT
APPEARS THAT ALL OF THE DATA SUPPORTS OCCASIONAL WAVES OF RAIN/SNOW
ESPECIALLY ACROSS THE CENTRAL MOUNTAINS AND UPPER SNAKE HIGHLANDS.
FARTHER SOUTH...WE HAVE LOWER CHANCES AS UNCERTAINTY ON THE
POSITION/STRENGTH OF THE RIDGE IS IN QUESTION. IT DOES LOOK TO
REMAIN BREEZY AT TIMES. KEYES


&&

.AVIATION...A THREAT OF LOW CLOUDS AND FOG WILL CONTINUE FOR A FEW
OF OUR TAF SITES THROUGH THE NEXT 24 HOURS. HIGHER CLOUDS MAY KEEP
COVERAGE DOWN...ALTHOUGH IT DIDN`T HAVE ANY EFFECT ON FORMATION THIS
MORNING. THE TAF SITES MOST LIKELY AFFECTED WOULD BE KIDA AND KPIH.
RIGHT NOW THE TAFS FOR BOTH AIRPORTS ONLY SHOW MVFR. DON`T SURPRISED
TO SEE IFR/LIFR WEATHER ON OCCASION...AS WE HAVE SEEN HAVE SEEN IT
MEANDER IN AND OUT AT BOTH SITES ERRATICALLY.  KSUN SHOULD REMAIN
VFR WITH NO STRATUS TO WORK INTO THE VALLEY DURING THE DAY AND FROM
THE SOUTH OR ANY EXPECTED TO FORM OVERNIGHT. KBYI HAS BEEN RIGHT ON
THE EDGE OF THINGS THAT PAST COUPLE OF MORNING AND SHOULD BE THE
SAME. KEYES

&&

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

$$







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