FXUS66 KOTX 011403 CCA
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
400 AM PST TUE DEC 1 2009
.SYNOPSIS...
A WEAK PACIFIC FRONT WILL MOVE SOUTHEAST OF THE AREA TODAY WITH A
FEW LINGERING SNOW SHOWERS OVER THE PANHANDLE MOUNTAINS AND THE
CAMAS PRAIRIE. DRY CONDITIONS WILL PREVAIL FOR THE REST OF THE WEEK
UNTIL ANOTHER POTENTIAL WEATHER SYSTEM MOVES INTO THE REGION BY
FRIDAY. TEMPERATURES WILL REMAIN NEAR SEASONAL NORMALS THROUGH THIS
WEEK...WITH A SHARP COOL DOWN POSSIBLE BY NEXT WEEKEND.
&&
.DISCUSSION...
FOR TODAY AND TONIGHT...A SHORTWAVE RIDGE WILL AMPLIFY ALONG THE
WEST COAST...GRADUALLY LEAVING THE INLAND PACIFIC NORTHWEST IN A DRY
NORTHERLY FLOW BY LATE TODAY. CURRENTLY...A SHORTWAVE TROUGH IS
DIVING SOUTHEASTWARD ALONG THE CONTINENTAL DIVIDE BRINGING FLURRIES
TO FAR EASTERN WASHINGTON AND LIGHT SNOW SHOWERS TO THE HIGHER
TERRAIN OF THE IDAHO PANHANDLE. AS THE FLOW VEERS TO A MORE
NORTHERLY COMPONENT THIS MORNING THERE WILL BE A THREE TO FIVE HOUR
WINDOW WHERE SNOW WILL BE POSSIBLE ACROSS THE CAMAS PRAIRIE...AND
THE CLEARWATER AND BLUE MOUNTAINS. HOWEVER...THE COLDER AIR ALOFT
AND RESULTING DESTABILIZATION...IS CURRENTLY LAGGING BEHIND THE
MOISTURE THAT IS MOVING SOUTHEASTWARD ACROSS SOUTHEASTERN WA AND THE
ID PANHANDLE. AS A RESULT...ACCUMULATIONS WILL BE RATHER MINIMAL
WITH AN INCH OR LESS OF SNOW EXPECTED ACROSS THE MOST FAVORED
LOCALES. IN ADDITION...AN INTRUSION OF LOW LEVEL DRY AIR IS
CURRENTLY UNDERWAY AS A WEAK FRONT DIVES SOUTHWARD OUT OF BRITISH
COLUMBIA. THIS DRY AIR HAS ERODED MUCH OF THE FOG AND STRATUS THAT
HAS BEEN PRESENT ACROSS THE INLAND PACIFIC NORTHWEST FOR THE PAST
COUPLE OF DAYS. HOWEVER...BEFORE THE DRY AIR MOVED INTO EASTERN
WASHINGTON AND NORTHERN ID...LOCALLY DENSE FOG REDEVELOPED LAST
NIGHT. IT APPEARS THAT THE DRY IS CURRENTLY WINNING THE BATTLE AND
MUCH OF THE FOG THAT DEVELOPED LAST NIGHT IS EITHER LIFTING AND/OR
DISSIPATING ENTIRELY ALTOGETHER ACROSS NORTHEASTERN WA AND NORTHERN
ID. AS A RESULT...LEFT PATCHY FOG ACROSS NORTHEASTERN WASHINGTON AND
THE ID PANHANDLE...BUT ANY REMAINING FOG AT DAYLIGHT WILL DISSIPATE
QUICKLY. IN ADDITION...GUSTY NORTH WINDS HAVE BEEN OBSERVED ACROSS
MUCH OF THE OKANOGAN VALLEY AND WATERVILLE PLATEAU THIS MORNING.
EXPECT THE CURRENT 5MB NORTH TO SOUTH PRESSURE GRADIENT ACROSS
WASHINGTON AND 20KT WINDS AT 850MB TO GRADUALLY SUBSIDE THIS
MORNING...WHICH WILL RESULT IN DECREASING WINDS ACROSS THE OKANOGAN
VALLEY TODAY. FOR THE REST OF TODAY AND TONIGHT...EXPECT GRADUAL
CLEARING AREA WIDE FROM NORTH TO SOUTH AS THE SHORTWAVE RIDGE BUILDS
INTO THE REGION. EXPECT MUCH COLDER TEMPERATURES TONIGHT AS CLEAR
SKIES...LIGHT WINDS...AND DRIER AIR WILL ALLOW TEMPERATURES TO FALL
5 TO 10 DEGREES COLDER THAN THE PREVIOUS SEVERAL MORNINGS. THE FOG
THREAT TONIGHT SHOULD BE LARGELY CONFINED TO THE MOST PROTECTED
VALLEYS AS WELL. /NEUMAN
WEDNESDAY THROUGH THURSDAY NIGHT...MAINLY DRY BUT COLD CONDITIONS
WILL PREVAIL DURING THE MID WEEK PERIOD. MEDIUM RANGE MODELS ARE
STILL ADVERTISING QUITE DIFFERENT WEATHER PATTERNS BUT THE END
RESULT WILL BE RATHER BENIGN WEATHER FOR THE INLAND NORTHWEST. WHILE
THE ECMWF HOLDS ONTO AN UPPER LEVEL RIDGE OVER THE PACIFIC
NORTHWEST...THE LATEST GFS GUIDANCE BRINGS A SHORTWAVE UP AND OVER
THE RIDGE BUT FAR ENOUGH NORTH TO HAVE LITTLE EFFECT ON THE FORECAST
AREA. POPS WERE REMOVED FROM THE THURSDAY NIGHT PERIOD AS ANY
MOISTURE AND FORCING WILL REMAIN WELL TO OUR NORTH. TEMPERATURES
WILL START OUT ON THE COOL SIDE OF SEASONAL NORMALS ON WEDNESDAY
THEN MODERATE A BIT ON THURSDAY AS LOW LEVEL FLOW BECOMES MORE
SOUTHERLY.
FRIDAY THROUGH MONDAY...THERE CONTINUES TO BE QUITE A DIFFERENCE IN
SYNOPTIC PATTERNS BETWEEN THE EC AND GFS THROUGH THE EXTENDED
PERIOD. THE GFS HAS A BROAD TROUGH SAGGING DOWN FROM CENTRAL CANADA
WHILE THE EC CLOSES OFF A LOW OFF THE WA/OR COAST. NO CHANGES
MADE TO THE EXTENDED POPS AFTER 00Z SATURDAY AS CONFIDENCE REMAINS
LOW. THERE IS SOME MODEL AGREEMENT ON BRINGING SOME VERY COLD AIR
SOUTH INTO THE INLAND NORTHWEST. 850MB TEMPS PLUNGE TO THE -12 TO
-15C RANGE ACROSS THE NORTHEAST ZONES BY SUNDAY MORNING. THE 12Z
ECMWF WAS NOT AS AGGRESSIVE AS THE GFS BUT NOW THE 00Z RUN IS
NEARLY AS COLD. WHILE NOT IN RECORD TERRITORY...THIS WILL LIKELY
BE THE COLDEST TEMPERATURES SO FAR THIS SEASON. ANOTHER AREA OF
AGREEMENT IS THAT STRONG WINDS WILL BE POSSIBLE OVER THE WEEKEND.
AS SURFACE HIGH PRESSURE DROPS SOUTHEAST FROM BRITISH COLUMBIA TO
CENTRAL MONTANA SATURDAY NIGHT...THE PRESSURE GRADIENT BETWEEN
THIS HIGH AND THE LOW OFF THE COAST TIGHTENS...RESULTING IN
STRENGTHENING WINDS. AS THESE WINDS ARE CHANNELED DOWN THE PURCELL
TRENCH...THERE IS THE POTENTIAL FOR WINDY CONDITIONS FROM NORTH
IDAHO DOWN TO THE COLUMBIA BASIN. THE COMBINATION OF COLD AND
GUSTY WINDS COULD RESULT IN WIND CHILL TEMPERATURES BELOW ZERO.
/KELCH
&&
.AVIATION...
HIGH PRESSURE WILL BUILD ALONG THE WEST COAST BRINGING CLEARING
SKIES AND DECREASING WINDS THROUGH THE DAY AREA WIDE. IN THE MEAN
TIME...NORTHWEST FLOW AND LINGERING MOISTURE WILL RESULT IN A CHANCE
OF BRIEF MVFR AND IFR CIGS AT KPUW AND KLWS THROUGH 17Z...BUT
CONDITIONS WILL BE PREDOMINANTLY VFR. THOUGH SKIES WILL BE CLEAR
TONIGHT...THE DRY AIR FILTERING INTO THE REGION SHOULD BE ENOUGH TO
PREVENT FOG FORMATION SO VFR CONDITIONS ARE EXPECTED AREA WIDE
THROUGH 12Z WEDNESDAY EXCEPT IN THE MOST PROTECTED VALLEYS. /NEUMAN
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 37 20 32 20 33 22 / 0 0 0 0 0 0
COEUR D'ALENE 39 22 35 19 36 24 / 0 0 0 0 0 0
PULLMAN 38 23 32 22 35 24 / 10 0 0 0 0 0
LEWISTON 43 25 38 21 38 27 / 10 0 0 0 0 0
COLVILLE 39 21 35 21 37 26 / 0 0 0 0 0 0
SANDPOINT 35 20 31 16 31 18 / 0 0 0 0 0 10
KELLOGG 34 21 31 18 31 23 / 10 0 0 0 10 10
MOSES LAKE 42 19 36 20 36 21 / 0 0 0 0 0 0
WENATCHEE 41 26 38 22 39 27 / 0 0 0 0 0 0
OMAK 41 21 36 22 38 25 / 0 0 0 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
WA...NONE.
&&
$$
