FXUS66 KOTX 102238
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
238 PM PST THU DEC 10 2009
.SYNOPSIS...
A SLOW WARMING TREND CAN BE EXPECTED INTO THE WEEKEND...HOWEVER
TEMPERATURES WILL REMAIN WELL BELOW NORMAL FOR THIS TIME OF YEAR.
A MOIST STORM SYSTEM WILL APPROACH THE OREGON-WASHINGTON BORDER
SATURDAY RESULTING IN A CHANCE OF LIGHT TO MODERATE SNOW EXTENDING
FROM THE BLUE MOUNTAINS TO THE CENTRAL IDAHO PANHANDLE. THE WET
WEATHER WILL CONTINUE TO SURGE NORTH INTO EARLY NEXT WEEK
RESULTING IN WET AND WARMER WEATHER FOR ALL LOCATIONS.
&&
.DISCUSSION...
TONIGHT AND FRIDAY...THE INLAND NORTHWEST WILL REMAIN UNDER THE
INFLUENCE OF A COOL AND MAINLY DRY NORTHWEST FLOW TONIGHT...SLOWLY
TRANSITIONING TO WESTERLY FLOW FRIDAY AFTERNOON. MEANWHILE A SHORT
WAVE WILL UNDER CUT THE FLOW AND TAKE A TRACK INTO SOUTHERN OREGON.
FOR TONIGHT THE NORTHWEST FLOW WILL KEEP COOL AIR FILTERING INTO
THE REGION. SATELLITE PICTURES SHOW A DRY SLOT MOVING INTO THE
NORTHEAST ZONES RIGHT NOW...HOWEVER ANOTHER SURGE OF MID AND UPPER
LEVEL MOISTURE IS QUICKLY MOVING IN BEHIND THE DRY SLOT. AS SUCH
EXPECT A BRIEF BREAK IN OVERCAST CONDITIONS ACROSS THE NORTHEAST
HALF OF MY CWFA LATE THIS AFTERNOON...EARLY EVENING BEFORE FILLING
BACK IN. SOME RADIATIONAL COOLING IS POSSIBLE AS THE CLEARING
MOVES THROUGH THE AREA BUT NOTHING BIG. 85H TEMPERATURES WARM A
DEGREE OR TWO AND WITH CONTINUING OVERCAST TEMPERATURES SHOULD SEE
ONLY MINOR CHANGES FROM THIS MORNING. FURTHER WEST UNDER CLEAR
SKIES EXPECT THE BEST RADIATIONAL COOLING AND THE COOLEST
TEMPERATURES. WITH THE INCOMING MID LEVEL MOISTURE THERE WILL
STILL BE VERY LOCALIZED AREAS OF SNOW FLURRIES MAINLY ALONG THE
UP-SLOPING AREAS OF THE PANHANDLE MOUNTAINS.
FOR FRIDAY THE FLOW BEGINS TO SHIFT TO WEST-NORTHWEST THROUGH THE
DAY. THIS WILL ALLOW THE MID LEVEL MOISTURE TO BACK NORTH ALONG
THE CANADIAN BORDER AND KEEP THE BEST CHANCES OF SNOW FLURRIES OR
SHOWERS TIED TO THE HIGHER TERRAIN ALONG THE NORTHERN MOUNTAINS.
OTHERWISE A DRY FORECAST IS IN STORE. 85H TEMPERATURES WILL
INCREASE 3-4C BY FRIDAY AFTERNOON AND WITH CLEARING SKIES EXPECT A
WARM UP OF 2-4 DEGREES OVER TODAY. /TOBIN
FRIDAY NIGHT THROUGH SUNDAY...MODELS ARE IN GENERAL AGREEMENT
DURING THIS PORTION OF THE FORECAST PERIOD. A WEST-EAST ORIENTED
WAVE WILL MOVE UP FROM OREGON ON SATURDAY AND THEN STALL SAT
NGT/SUNDAY AS IT ENCOUNTERS THE BROAD NW FLOW ASSOCIATED WITH THE
LONG WAVE TROUGH. THERE IS GENERAL AGREEMENT THAT THIS WAVE WILL
STALL ACROSS SOUTHERN WASHINGTON EXTENDING EAST INTO THE IDAHO
PALOUSE AND THE CENTRAL PANHANDLE MOUNTAINS. ALSO WITH THE BROAD
NW FLOW...AND 850MB WINDS OUT OF THE WEST...MODELS SHOW AN
ENHANCEMENT IN PRECIP OVER THE UPSLOPE AREAS OF THE PALOUSE AND
THE CENTRAL PANHANDLE MOUNTAINS. 1000-850MB THICKNESSES FROM ALL
MODELS REMAIN AT OR BELOW 1300DM THROUGH THE EVENT SUGGESTING SNOW
WILL BE THE PRECIP TYPE FOR ALL ELEVATIONS. QPF AMOUNTS FROM THE
GFS AND ECMWF SAT NGT/SUNDAY RANGE FROM A HALF INCH TO THREE
QUARTERS OF AN INCH...WITH MODERATE UPWARD OMEGA IN THE DENDRITIC
GROWTH ZONE. GOING WITH A CONSERVATIVE 13:1 RATIO WOULD YIELD
POSSIBLE HEAVY SNOW ACCUMULATIONS. FOR NOW WILL ISSUE A HAZARDOUS
WEATHER OUTLOOK FOR THE PALOUSE AND CENTRAL PANHANDLE MTNS. THE
NE BLUES MAY RECEIVE SIGNIFICANT SNOWFALL AS WELL BUT CONFIDENCE
IS LOWER HERE AS THE BAND OF HEAVIER SNOW MAY SET UP JUST NORTH OF
THE BLUES. ELSEWHERE A GRADUAL INCREASE IN SNOW CHANCES IS
EXPECTED SAT NGT/SUNDAY AS LARGE SCALE FORCING INCREASES AHEAD OF
A STRONG SHORT WAVE AND AN ARCTIC FRONT BEGINS TO SAG SOUTH IN
BRITISH COLUMBIA. ALTHOUGH THE NORTHWEST FLOW WILL LIKELY KEEP THE
HIGHEST PRECIPITATION CHANCES IN THE CASCADES AND THE MTNS OF NE
WA/N IDAHO AS DOWNSLOPE FLOW OFF THE CASCADES LIMIT PRECIP CHANCES
FOR PLACES LIKE OMAK...WENATCHEE...AND MOSES LAKE. TEMPERATURES
WILL REMAIN BELOW NORMAL THROUGH THE PERIOD. JW
SUNDAY NIGHT...THE BLOCKING UPPER LEVEL RIDGE RETREATS TO ALASKA WHILE
WESTERLY FLOW BREAKS THROUGH AND BRINGS PACIFIC ENERGY AND
MOISTURE TO THE FORECAST AREA. A STATIONARY FRONT WILL BECOME
STALLED OVER THE LOWER BASIN INTO THE PALOUSE REGION AND CENTRAL
IDAHO PANHANDLE WITH SNOW LIKELY. MEANWHILE..THE MONSTER LOW IN
CANADA PIVOTS AND SENDS A SHORTWAVE SOUTH ACROSS THE WESTERN
PROVIDENCES AND INTO THE NORTHERN ROCKIES AS A BACK DOOR COLD
FRONT. THIS WILL PUSH THE STALLED PACIFIC FRONT SOUTHEAST OUT OF
THE REGION AND BRING ANOTHER SHOT OF COLD ARCTIC AIR. SNOW SHOWERS
WILL CONTINUE IN THE PANHANDLE MOUNTAINS AND SOUTHEAST
WASHINGTON...WITH ANOTHER INCH POSSIBLE. TEMPERATURES WILL TAKE A
PLUNGE WITH LOW LEVEL COLD AIR ADVECTION AND INCREASED NORTHERLY
WINDS ACROSS THE NORTHERN TIER ZONES...WITH 850MB TEMPS FALLING
INTO THE MINUS TEENS CELSIUS BY EARLY MONDAY MORNING.
MONDAY...NORTHWEST FLOW ALOFT CONTINUES AS A SHORTWAVE RIDGE
BUILDS ALONG THE COAST. LINGERING OROGRAPHIC SNOW SHOWERS WILL
PERSIST IN THE PANHANDLE UNDER NORTHERLY LOW LEVEL FLOW...WHILE
CLEARING AND COLDER CONDITIONS SEEP IN FROM THE NORTH. MEANWHILE...A
RENEWED LOW IS DEVELOPING IN THE ERN PACIFIC WITH A WARM FRONT
REACHING THE CASCADES WILL BRING A RETURN OF SNOW LATE IN THE DAY.
MONDAY NIGHT THROUGH THURSDAY...THE DIFFERING MODEL SOLUTIONS IN
THE PAST RUNS ARE TRYING TO CONVERGE AS A SERIES OF PACIFIC
STORMS SYSTEMS TAKE AIM ON THE PACIFIC NORTHWEST. THE GFS SHOWS A
BETTER TIMING AND POINTS OUT TWO ROUNDS OF PRECIPITATION...MAINLY
TUESDAY AND AGAIN LATE WEDNESDAY. THE CANADIAN AND ECMWF SHOW
LITTLE BREAK BETWEEN THE TWO SYSTEMS AND INDICATE A BROAD WET
PERIOD. TEMPERATURE POSE AN ISSUE WITH THESE TWO SYSTEMS...SINCE
EACH IS BRINGING IN WARMER AIR. THE GFS AND DGEX ARE THE COLDER
MODELS...KEEPING THE COLDER AIR THAT PENETRATED THE REGION BY
MONDAY THROUGH MID WEEK BEFORE ERODING IT. THIS WOULD BRING SNOW TO
MOST OF THE REGION THROUGH TUESDAY EVENING...AND THEN A RAIN/SNOW
MIX BY LATE WEDNESDAY. THE CANADIAN AND ECMWF ARE SOMEWHAT MILDER
WITH SNOW CHANGING TO RAIN IN THE BASIN AND LOWER VALLEYS WITH THE
BEST CHANCE OF SNOW IN THE NORTHERN MOUNTAINS BY TUESDAY
AFTERNOON...AND THEN EVEN WARMER TEMPERATURES ARE FORECAST FOR MID
WEEK. YET BOTH THE CANADIAN AND ECMWF ARE TRENDING COLDER THAN
THEIR PREVIOUS RUNS. AT THIS TIME...WILL LEAN MORE TOWARD A COLDER
GFS REGIME ESPECIALLY FOR THE TUESDAY SYSTEM WITH NORTHEAST
WINDS...AND THEN INDICATE SOME MODERATION OF TEMPERATURES AND
MIXED PRECIPITATION TYPE BY MID WEEK AS THE LOW LEVEL FLOW BECOMES
MORE SOUTHERLY. /RFOX.
&&
.AVIATION...
A DRY NORTHWEST FLOW TODAY AND TONIGHT WILL RESULT IN MAINLY VFR
CONDITIONS AND LIGHT WINDS. A MID LEVEL DECK WILL REMAIN ACROSS
THE NORTHEAST HALF OF THE FORECAST AREA. CIGS WILL RANGE FROM
090-110 AND SNOW FLURRIES OVER THE HIGHER TERRAIN WILL RESULT IN
SOME MOUNTAIN OBSCURATIONS. /TOBIN
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 8 24 12 23 17 25 / 0 0 0 20 50 50
COEUR D'ALENE 10 25 14 24 20 26 / 0 0 0 30 50 60
PULLMAN 9 25 16 28 24 29 / 0 0 10 70 70 70
LEWISTON 11 29 17 30 26 33 / 0 0 10 50 70 60
COLVILLE 8 22 14 23 20 27 / 0 0 10 20 20 50
SANDPOINT 7 20 10 23 18 23 / 0 10 20 40 40 60
KELLOGG 8 22 14 25 24 26 / 10 0 0 60 70 80
MOSES LAKE 2 25 9 23 13 27 / 0 0 0 20 20 10
WENATCHEE 6 25 11 23 17 28 / 0 0 0 20 20 10
OMAK 3 25 7 22 12 28 / 0 0 10 20 20 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
WA...NONE.
&&
$$
