FXUS66 KOTX 010418
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
818 PM PST MON NOV 30 2009
.SYNOPSIS...
A WEAK PACIFIC FRONT WILL MOVE THROUGH THE AREA TONIGHT BRINGING
LIGHT PRECIPITATION TO THE CASCADES AND PANHANDLE MOUNTAINS. DRY
CONDITIONS WILL PREVAIL FOR THE REST OF THE WEEK UNTIL ANOTHER
POTENTIAL WEAK WEATHER SYSTEM MOVES INTO THE REGION BY THURSDAY
NIGHT OR FRIDAY. TEMPERATURES WILL REMAIN AROUND SEASONAL
NORMALS THROUGH THIS WEEK...WITH A SHARP COOL DOWN POSSIBLE BY
NEXT WEEKEND.
&&
.DISCUSSION...
UPDATE FOR TONIGHT...FOG HAS AGAIN BEGUN TO FORM ACROSS THE WEST
PLAINS. DRY AIR GRADUALLY ADVECTING IN FROM THE OKANOGAN VALLEY
HAS BEEN RATHER SLOW TO DISSIPATE THE FOG AND STRATUS OVER THE
COLUMBIA BASIN AND SPOKANE AREA THIS EVENING. HOWEVER...THE BACK
EDGE OF FOG/STRATUS PER FOG IMAGERY SEEMS TO BE BEARING DOWN ON
MOSES LAKE AND THE WEST PLAINS AS OF 8 PM. ADDITIONALLY...THE N-S
PRESSURE GRADIENT DOWN THE OKANOGAN VALLEY DOES SEEM TO BE
STRENGTHENING PER THE LATEST OMAK OBSERVATION WITH NORTH WINDS
BLOWING AT 15 KTS AND GUSTING TO NEAR 20 KTS. IN ADDITION...THE
DEWPOINTS IN THE OKANOGAN VALLEY CONTINUE TO FALL TOWARD 20F AS WE
SPEAK...SO DRIER AIR DOES SEEM TO REALLY BE COMING...ALBEIT A BIT
SLOWER THAN THE FORECAST INDICATED. AS A RESULT...FOG WILL NOT BE
ADDED TO THE OVERNIGHT FORECAST FOR THE SPOKANE AREA...AS IT SEEMS
IT SHOULD DISSIPATE JUST AS QUICK AS IT FORMS.
ELSEWHERE...NORTHWESTERLY LOW LEVEL FLOW BEHIND THE SOUTHEASTWARD
MOVING COLD FRONT FROM THIS EVENING WILL MEAN UPSLOPE SNOW SHOWERS
SHOULD DEVELOP BY LATE TONIGHT AND EARLY TOMORROW MORNING ACROSS
THE CAMAS PRAIRIE. MODEL CROSS SECTIONS PER THE 00Z NAM AND GFS
BOTH EXTEND THE SURFACE MOIST LAYER UP TO NEAR OR JUST ABOVE THE
-10C ISOTHERM...OR INTO THE LOWEST REACHES OF THE DENDRITIC GROWTH
REGION. IN ADDITION...UPSLOPE NEGATIVE OMEGAS ARE
NOTED...ESPECIALLY ON THE NAM. ALSO AT THE VERY TOP OF THE MOIST
LAYER...THETA-E LAPSE RATES GO NEGATIVE OVER A VERY SMALL LAYER IN
THE NEGATIVE OMEGAS. AS A RESULT...EVEN WITH A RATHER SMALL MOIST
LAYER...IT MAY BE JUST DEEP ENOUGH TO GET AN INCH OF UPSLOPE SNOW
OVER THE CAMAS PRAIRIE THROUGH THE MORNING HOURS ON TUESDAY.
OTHERWISE...DRIER AIR INVADING SHOULD ERADICATE ANY CHANCES OF
SNOW ACROSS ALL AREAS OF THE CWA BY AFTERNOON. /FRIES
&&
.AVIATION...
A COLD FRONT STRETCHING FROM KOMK TO CWJR AT 00Z WILL MOVE TO KDLS
TO KLWS BY 06S TONIGHT. AHEAD OF THE FRONT STUBBORN IFR AND LIFR
STRATUS WILL PERSIST IN THE COLUMBIA BASIN MAINLY IMPACTING KMWH AND
KGEG...WITH VFR CONDITIONS UNDER HEAVY MID LEVEL CLOUDS ELSEWHERE.
THE FRONT WILL ALSO PROMOTE SIOLATED TO SCATTERED MOUNTAIN SNOW
SHOWERS NORTH AND EAST OF THE COLUMBIA BASIN. AFTER THE FROPA DRY
AIR WILL SCRUB REMAINING STRATUS OUT OF THE BASIN WITH VFR
CONDITIONS THROUGH OUT THE REGION UNTIL THE END OF THE TAF PERIOD AT
00Z WEDNESAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
SPOKANE 25 35 21 32 21 35 / 10 0 0 0 0 0
COEUR D'ALENE 27 38 23 33 21 37 / 20 0 0 0 0 10
PULLMAN 30 35 23 32 23 36 / 20 10 0 0 0 10
LEWISTON 36 45 25 38 24 41 / 0 0 0 0 0 0
COLVILLE 27 36 21 35 23 38 / 20 0 0 0 0 10
SANDPOINT 25 32 21 31 17 33 / 20 0 0 0 0 10
KELLOGG 28 33 21 30 20 34 / 40 20 0 0 0 10
MOSES LAKE 27 40 21 35 21 37 / 0 0 0 0 0 10
WENATCHEE 31 41 28 38 23 39 / 0 0 0 0 0 10
OMAK 26 38 23 37 25 38 / 10 0 0 0 0 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...NONE.
WA...NONE.
&&
$$
