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000
FXUS65 KPIH 051949
AFDPIH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
1249 PM MST WED MAR 5 2014

.SHORT TERM...TONIGHT THROUGH SATURDAY. UPPER RIDGING OVER THE
REGION TODAY WILL FLATTEN TO MORE ZONAL FLOW AS A NEW STORM
SYSTEM MOVES INTO THE PAC NW TONIGHT. AS THE UPPER FLOW TURNS TO
THE SW...PRECIP MOVE INTO THE FCST AREA BY THU MORN. THE MOST
SIGNIFICANT PRECIP WILL BE OVER THE WEST FACING MTNS DUE TO
UPSLOPE ENHANCEMENT. THE REST OF THE AREA WILL SEE LESSER AMOUNTS.
SW FLOW TRANSLATES TO WARM TEMPS...SO SNOW LEVELS WILL REMAIN
HIGH. SEVERAL INCHES OF SNOW IS EXPECTED TO FALL IN THE CENTRAL
MTNS BY THU EVE...WITH A LITTLE LESS IN THE EASTERN HIGHLANDS.
SIGNIFICANT ACCUMULATIONS ARE EXPECTED TO BE MAINLY ABOVE 6500 FT.
PRECP TAPERS OFF TO MAINLY MTN SNOW SHOWERS ON FRI AS THE UPPER
TROF MOVES TO THE EAST. UPPER RIDGING AGAIN BECOMES THE DOMINANT
FEATURE BY FRI EVE...RESULTING IN DRY CONDITIONS THRU SATURDAY.

WINDY CONDITIONS CAN BE EXPECTED INTO THIS EVE AND AGAIN FRI AFTN
WITH THE PASSAGE OF THE STORM SYSTEM. TEMPS WILL BE A LITTLE
COOLER FRIDAY AND FRIDAY NIGHT...BUT BEGIN RECOVERING SATURDAY
UNDER THE INFLUENCE OF THE BUILDING UPPER RIDGE.  HEDGES

.LONG TERM...AT NIGHT THROUGH NEXT WED NIGHT. 500MB LONGWAVE FLOW
IS NEARLY ZONAL WITH A VERY LOW AMPLITUDE RIDGE OVER THE NORTHERN
GREAT BASIN THAT RETROGRADES BY TUE TO THE COAST. THIS SHOULD MEAN
MILD TEMPERATURES UNLESS SOME SIGNIFICANT SHORTWAVE MOVES THROUGH
THESE MEAN WESTERLIES...BUT IT WILL ALSO MEAN A VERY UNCERTAIN
FORECAST FOR TIMING SHORTWAVES AS IT WILL VARY NOT ONLY FROM RUN TO
RUN BUT ALSO AMONGST THE PRODUCT SUITES. NO EXCEPTION TO THOSE TWO
ISSUES TODAY. THE SOLUTION DIFFERENCES BETWEEN THE GFS AND THE ECMWF
START BY SUN NIGHT. AN INCOMING SHORTWAVE GETS HUNG UP AND SLOWED BY
THE GFS...NOT SOMETHING THAT THE USUAL PROGRESSIVE GFS IS KNOWN FOR.
BUT THE ECMWF BRINGS IT THROUGH SUN NIGHT. THE ECMWF THEN BRINGS
ANOTHER SHORTWAVE IN ON MON NIGHT WHILE THE GFS APPEARS TO TAKE THIS
NEXT INCOMING SHORTWAVE AND HAVE IT DEEPEN AND SLOW OVER
OREGON...MAKING A MUCH DRIER MON NIGHT. BY TUE AFTERNOON...BOTH THE
GFS AND ECMWF DEVELOP UPPER LEVEL NORTHWEST TO NORTH FLOW IN THE
WAKE OF THESE SHORTWAVES. THIS DOES BRING A COOL DOWN...BUT IT
BRINGS TEMPERATURES ACTUALLY BACK TO NEAR NORMAL. POPS FOR THIS
EARLY PART OF THE UPCOMING WORK WEEK ARE VERY HIGH FOR THE
ECMWF...POCATELLO IS FORECASTED LIKELY POPS WHILE THE GFS KEEPS THEM
IN THE LOW CHANCE CATEGORY. THE LAST THIRD OF THE PERIOD IS TENDING
TO BE DRIER WITH THE MORE NORTHERLY FLOW. HAVE TRIED TO SPLIT THE
DIFFERENCE UNTIL THERE IS BETTER AGREEMENT...EITHER WAY.  MESSICK

&&

.AVIATION...HRRR AND NAM ARE ONCE AGAIN DELAYING THE ONSET OF WIND
AND THE ONSET OF PRECIPITATION TONIGHT...SO HAVE BACKED OFF SOME
FROM PREVIOUS SET OF TAFS. BASED ON VERTICAL MOISTURE PROFILE...HAD
TO KEEP KSUN CLOSED WITH IFR CIGS AFTER 06/07Z EVEN THOUGH BOTH MOS
PRODUCTS CONTINUE TO FORECAST VFR. THE CIGS MAY STAY THIS WAY
BECAUSE PRECIPITATION TYPE IS RAIN OVERNIGHT...WHICH IS LIKELY NOT
THE USUAL CASE FOR KSUN AT THIS TIME OF YEAR. THE ONLY OTHER
AIRDROME EXPECTED TO HAVE ISSUES THU MORNING WHEN FRONT IS OVERHEAD
IS KIDA WITH IFR. TEMPERATURES SHOULD STAY ABOVE FREEZING FOR THE
AIRPORTS. KBYI AND KPIH WILL BE IN PRECIPITATION SHADOW AND
PRECIPITATION DEVELOPMENT WILL NEED A SHIFT TO SOUTHWEST AND WEST
WIND BEFORE IT DEVELOPS...SOMEWHERE IN THE VICINITY OF 06/12Z OR SO.
MESSICK

&&

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

$$