666
FXUS66 KOTX 190543
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
943 PM PST WED DEC 18 2024
SYNOPSIS
A RIDGE OF HIGH PRESSURE WILL RESULT IN A DRYING TREND AND CALMER
WINDS THROUGH FRIDAY. UNSETTLED WEATHER WILL RETURN THIS WEEKEND
AND CONTINUE INTO NEXT WEEK. MILD TEMPERATURES WILL RESULT IN
PRECIPITATION FALLING PRIMARILY AS VALLEY RAIN AND MOUNTAIN SNOW.
DISCUSSION
KEY POINTS:
* WINDS WILL DECREASE THROUGH THIS EVENING AND BECOME LIGHT
OVERNIGHT.
* MILD TEMPERATURES AND DRY OVER MUCH OF THE INLAND NORTHWEST
THROUGH FRIDAY.
* UNSETTLED WEATHER THIS WEEKEND INTO NEXT WEEK WITH VALLEY RAIN
AND MOUNTAIN SNOW RETURNING.
TONIGHT THROUGH FRIDAY NIGHT: HIGH PRESSURE WILL BEGIN TO BUILD IN
OVER THE REGION TONIGHT. THE PRESSURE GRADIENT PRODUCING THE GUSTY
WINDS ACROSS THE REGION WILL RELAX AND WILL SEE WINDS CALMING DOWN
OVERNIGHT. A WARM FRONT WILL APPROACH OFF OF THE EASTERN PACIFIC AND
THIS WILL FORM THIN HIGH CLOUDS OVER EASTERN WASHINGTON. WHAT WE SEE
IN THE WAY OF LOW LEVEL CLOUDS IS MORE UNCERTAIN AS OUR WINDS TODAY
HAS MIXED A SIGNIFICANT AMOUNT OF DRIER AIR DOWN INTO THE BOUNDARY
LAYER. THIS SHOULD LIMIT THE STRATUS COVER THAT DEVELOPS, AND THE
12Z NAM GUIDANCE IN PARTICULAR LOOKS TO BE A BIT OVERDONE. THE
APPROACHING WARM FRONT WILL INCREASE THE EASTERLY FLOW IN THE
BOUNDARY LAYER THOUGH FOR THURSDAY, AND WILL LIKELY START TO SEE
LOW CLOUDS FORMING NEAR THE CASCADES AS THAT MOISTURE POOLS UP
AGAINST THE EAST SLOPES. MOISTURE WITH THIS FRONT WILL BE
LIMITED. THERE IS A 70 PERCENT CHANCE FOR PRECIPITATION AT THE
CASCADE CREST THURSDAY NIGHT. SNOW LEVELS WILL BE ABOVE PASS LEVEL
THOUGH WITH STEVENS PASS EXPECTED TO SEE RAIN. THOSE
PROBABILITIES DROP SIGNIFICANTLY AWAY FROM THE CASCADES WITH A 30
PERCENT CHANCE FOR PRECIPITATION OVER THE NORTHERN MOUNTAINS.
PRECIPITATION TYPE LOOKS TO BE A RAIN/SNOW MIX IN THE VALLEYS AND
LIGHT SNOW IN THE MOUNTAINS. ANY SNOW THAT FALLS THOUGH WILL BE
VERY LIGHT AND ISN'T EXPECTED TO RESULT IN IMPACTS. ANOTHER WEAK
SHORTWAVE DISTURBANCE WILL PUSH ACROSS THE CASCADES AND BRUSH THE
NORTHERN MOUNTAIN ZONES FRIDAY INTO FRIDAY NIGHT. THIS ONE WILL
LOOK VERY SIMILAR TO THE ONE THURSDAY NIGHT. LITTLE IN THE WAY OF
MOISTURE WITH IT, AND THE BUILDING RIDGE OVER THE REGION WILL
DIRECT THE BULK OF IT AND ASSOCIATED DYNAMICS NORTH INTO BC.
TEMPERATURES WILL BE MILD AND ABOVE NORMAL FOR MID DECEMBER.
EXPECT HIGH TEMPERATURES IN THE UPPER 30S AND 40S AND OVERNIGHT
LOWS DROPPING INTO THE MID 20S TO LOWER 30S. THESE TEMPERATURES
WILL GENERALLY BE 8-12 DEGREES ABOVE NORMAL. /SVH
SATURDAY THROUGH WEDNESDAY:
SEVERAL DISTURBANCES WILL PUSH THROUGH THE INLAND NORTHWEST AND LEAD
TO CHANCES FOR PRECIP THROUGH MUCH OF THE PERIOD. HOWEVER, ENOUGH
WARM AIR REMAINS THAT RAIN WILL BE THE PRIMARY PRECIP TYPE BELOW
3500 FEET, WITH SNOW GENERALLY CONFINED TO THE MOUNTAINS. NOT
LOOKING LIKE A GOOD RECIPE FOR A WHITE CHRISTMAS FOR MOST
COMMUNITIES, BUT CERTAINLY SOMETHING WE'LL BE WATCHING OVER THE
COMING DAYS.
ABOVE NORMAL HIGHS FOR THE PERIOD TYPICALLY IN THE UPPER 30S TO LOW
40S, WITH LOWS IN THE 20S TO LOW 30S. /KD
AVIATION
06Z TAFS: HIGH PRESSURE IS BUILDING OVER THE AREA. THIS HAS
RESULTED IN DECREASING WINDS AND CLEARING SKIES. OUTSIDE MOUNTAIN
CIRRUS, RADIATIONAL COOLING IS ALLOWING FOR FOG DEVELOPMENT
WITHIN THE NORTHERN MOUNTAIN VALLEYS AND THINKING LOW CLOUDS WILL
DEVELOP BETWEEN PULLMAN AND SPOKANE AND AROUND COEUR D ALENE. HREF
HAS A 70% CHANCE FOR CIGS BELOW 1000 FT AGL AT GEG BETWEEN
0300-0600. THIS WILL BE COMPETING WITH A SLIGHT INCREASE IN
EASTERLY WINDS SO ANY LOW CLOUDS THAT DEVELOP WILL DRIFT WESTWARD
INTO THE UPPER BASIN AND TOWARD MOSES LAKE-WENATCHEE-WATERVILLE.
GENERAL LOW CONFIDENCE IN THE FORECAST AND TRENDS MAY GO TOWARD
FOG VS STRATUS IF EASTERLY WINDS ARE SLOWER TO MATERIALIZE. FOG
HAS BEEN OBSERVED IN THE CASCADE VALLEYS ALREADY TONIGHT AND COULD
EXPAND ALONG THE COLUMBIA RIVER BTWN KEAT AND KOMK. MODERATE
CONFIDENCE FOR VFR SKIES FOR N IDAHO AND E WA TOMORROW ONCE
EASTERLY WINDS DEVELOP. LOWER CONFIDENCE FOR CENTRAL WA,
ESPECIALLY IF THE LOWER CLOUDS MATERIALIZE OVERNIGHT AND DRIFT
THIS DIRECTION.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
THERE IS POTENTIAL FOR VFR SKIES TO REMAIN IN PLACE AT THE
FORECAST SITES THROUGH 06Z TOMORROW. HOWEVER, GIVEN THE LATEST
TEMP/DEWPOINT SPREADS AND THIN MTN CIRRUS, FORECAST IS LEANING
TOWARD SOME RESTRICTIONS 10-15Z ALONG THE WA/ID BORDER AND INTO
CENTRAL WA 12-16Z. THE FORECAST COMES MODERATE TO LOW CONFIDENCE
AND ADDITIONAL AMENDMENTS ARE HIGHLY POSSIBLE. /SB
-----------------------
CONFIDENCE DESCRIPTORS:
LOW - LESS THAN A 30 PERCENT CHANCE
MODERATE - 30 TO 70 PERCENT CHANCE
HIGH - GREATER THAN A 70 PERCENT CHANCE
FOR ADDITIONAL PROBABILISTIC INFORMATION FOR NWS SPOKANE AIRPORTS,
PLEASE REFER TO THE AVIATION DASHBOARD ON OUR WEBPAGE:
HTTPS:/WWW.WEATHER.GOV/OTX/AVNDASHBOARD
PRELIMINARY POINT TEMPS/POPS
SPOKANE 30 39 33 43 32 42 / 0 0 10 0 10 30
COEUR D'ALENE 29 39 32 44 32 42 / 0 0 10 0 10 30
PULLMAN 31 40 34 46 34 44 / 0 0 0 0 0 40
LEWISTON 33 46 37 50 36 47 / 0 0 0 0 0 30
COLVILLE 24 36 30 39 29 39 / 0 10 30 0 20 30
SANDPOINT 28 36 32 41 31 39 / 0 10 20 10 20 20
KELLOGG 31 41 33 46 34 44 / 0 0 10 0 10 30
MOSES LAKE 30 42 33 44 33 42 / 0 10 10 0 0 50
WENATCHEE 31 37 32 40 33 39 / 0 10 10 0 0 40
OMAK 27 37 32 40 32 39 / 0 10 20 0 10 30
OTX WATCHES/WARNINGS/ADVISORIES
ID...NONE.
WA...NONE.
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