Winter Storm and Heavy Snow in Idaho, December 24 to 25, 2014

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE POCATELLO ID
301 AM MST WED DEC 24 2014

.SHORT TERM...TODAY THROUGH FRI NIGHT. APPROACHING STORM APPEARS
ON TRACK FOR A LATE NIGHT FRONTAL PASSAGE IN THE POCATELLO AREA.
WILL CONTINUE ADVISORIES AND THE HEAVY SNOW WARNING JUST AS THEY
ARE. HAVE ADDED IN BLOWING SNOW WHERE WIND IS STRONG ENOUGH AND
SNOW IS ACCUMULATING. BEHIND THE FRONT...POLAR AIR WILL SETTLE IN
AND THE FIRST PROLONGED COLD SPELL IN A MONTH WILL SETTLE IN.
SINGLE DIGIT TEMPERATURES EXPECTED IN THE NORTH END OF THE SNAKE
RIVER PLAIN AND IN THE USUAL ALPINE BASINS...BELOW ZERO FOR
CHRISTMAS NIGHT AND FRIDAY NIGHT IN THE STANLEY BASIN. CLOUDS IN
THE SOUTHEASTERN THIRD OF THE FORECAST AREA WILL KEEP THAT AREA
SLIGHTLY WARMER FOR CHRISTMAS NIGHT...BUT CLEARING SKIES AND
CONTINUED COLD ADVECTION WILL MAKE FOR 8 TO 10 DEGREE DROP FROM
TONIGHTS LOW TO THE CHRISTMAS NIGHT LOW. SNOW WILL CONTINUE IN
UPSLOPE AREAS...MAINLY IN THE CARIBOU HIGHLANDS WHERE THE
NORTHWEST FLOW IS PUSHES THE AIR UPHILL QUICKLY.

THE MAIN CONCERN IS WHAT WILL HAPPEN IN THE NORTHWEST FLOW IN THE
POCATELLO AREA. THERE IS THE POTENTIAL FOR SUBSTANTIALLY MORE SNOW
ON THE BENCH AREA COMPARED TO THE MORE LEVEL CENTRAL CITY. EVEN
THE NAM PICKED UP ON THIS WITH A LARGE GRADIENT OVER THE BANNOCK
RANGE.  MESSICK

.LONG TERM...SATURDAY THROUGH NEXT WEDNESDAY. THE ECMWF AND GFS
CONTINUE TO SHOW A VIGOROUS PAC TROUGH SWEEPING THROUGH THE REGION
SATURDAY NIGHT THROUGH SUNDAY NIGHT WITH WHAT LOOKS TO BE ADVISORY
LEVEL SNOW ACCUMULATIONS ACROSS THE REGION DURING THE HOLIDAY TRAVEL
PERIOD. DRIER CONDITIONS FOLLOW MONDAY INTO TUESDAY AS STRONG NORTH
WINDS DRIVE AN UNSEASONABLY COLD ARCTIC AIRMASS INTO THE REGION WITH
DAYTIME HIGHS RUNNING 15 TO 20 DEGREES BELOW NORMAL THROUGH EARLY
NEXT WEEK. HUSTON
&&

.AVIATION...INCREASING MID AND HIGH LEVEL CLOUDINESS WAS OBSERVED
SPILLING INTO SE IDAHO AHEAD OF A PAC TROUGH WHICH WAS ADVANCING
TOWARD THE NW COAST EARLY THIS MORNING. VFR OVC CONDITIONS ARE
EXPECTED TO PREVAIL AT TERMINAL LOCATIONS THROUGHOUT THE DAY BEFORE
DETERIORATING RAPIDLY LATE THIS AFTERNOON/EVE AS THE PAC TROUGH
SWEEPS INTO THE AREA. MODEL CROSS SECTIONS SHOW SATURATED/IFR
CONDITIONS DEVELOPING AT ALL TERMINALS OVERNIGHT WITH OCCASIONAL
LIFR CIGS IN MODERATE SNOW. PRECIPITATION WILL LIKELY BEGIN AS RAIN
AT MOST TERMINALS LATE THIS AFTERNOON/EVE THEN TRANSITION TO SNOW
LATER IN THE EVENING AS THE COLDER AIR FILTERS INTO THE REGION WITH
THE PASSING TROUGH. HUSTON
&&

.PIH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 PM THIS AFTERNOON TO 5 PM MST
THURSDAY IDZ017-019>024-032.

WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 2 PM MST
THURSDAY IDZ018-031.

WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 5 PM MST
THURSDAY IDZ025.

&&