742
FXUS66 KOTX 191118
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
318 AM PST THU DEC 19 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
TODAY AND FRIDAY: AFTER THE LAST COUPLE OF DAYS OF WINTER PRECIP
AND WIND, THE INLAND NORTHWEST WILL GET BREAK. A RIDGE WILL BRING
DRY, WARM CONDITIONS TO MOST LOCATIONS. ALONG THE CASCADES WILL BE
EXCEPTION. ENSEMBLES CONTINUE TO PUSH MOISTURE UP THE WESTERN
FLANK OF THE RIDGE ALONG THE CASCADES WITH A 30 PERCENT
PROBABILITY OF OCCURRING. THE PRECIP TYPE IS EXPECTED TO BE A
WINTRY MIX TO START. WITH WARM AIR BEING DRAWN IN FROM THE SOUTH,
THE SNOW LEVELS WILL CONTINUE TO INCREASE THROUGH DAY AND CAUSE
THE PRECIP TO BECOME MAINLY RAIN. ADDITIONAL SNOW AMOUNTS IN THE
AREA ARE NEAR ONE INCH. THE MAIN CONCERN FOR THE REST OF THE
REGION WILL BE THE MORNING IN THE BASIN AND VALLEYS. HIGHS ARE
EXPECTED TO AROUND 10 DEGREES ABOVE NORMAL IN THE 30S TO 40S
RANGE. OVERNIGHT LOWS WILL BE IN THE 20S TO LOW 30S. /JDC
SATURDAY THROUGH WEDNESDAY: WARM SOUTHWESTERLY FLOW WILL
PREVAIL WITH A RIDGE SITTING TO OUR EAST OVER THE CENTRAL US. A
SERIES OF SHORTWAVES WILL RIPPLE UP THE WEST SIDE OF THE RIDGE,
BRINGING SEVERAL ROUNDS OF WIDESPREAD PRECIP TO THE INLAND NORTHWEST
OVER THE WEEKEND AND THROUGH NEXT WEEK. SNOW LEVELS FLUCTUATING
BETWEEN 3500 AND 5500 FEET WILL KEEP SNOW CONFINED TO HIGHER
MOUNTAIN PASSES FOR THE MOST PART. LOWER ELEVATIONS CAN EXPECT
PRECIPITATION IN THE FORM OF RAIN. LOWLAND LOCATIONS NORTH OF
HIGHWAY 2 MAY BE AN EXCEPTION IF PRECIPITATION FALLS AT NIGHT WHEN
TEMPERATURES ARE COOLER AND SNOW LEVELS LOWER. ISOLATED POCKETS OF
FREEZING RAIN WILL BE POSSIBLE FOR THE CASCADE VALLEYS, BUT CHANCES
ARE SLIM FOR MORE THAN A TRACE OF ACCUMULATION. DAYTIME HIGHS WILL
BE CONSISTENTLY IN THE 30S TO LOW 40S, AND LOWS WILL BE IN THE 20S
TO LOW 30S. LONG-RANGE MODELS ARE SUGGESTING A TROUGH MAY MOVE
INLAND ON WEDNESDAY (CHRISTMAS DAY), WHICH COULD POTENTIALLY LOWER
SNOW LEVELS ENOUGH FOR LOWLANDS TO SEE A FEW FLAKES BY WEDNESDAY
NIGHT. CONFIDENCE IN THE FORECAST IS LOW THAT FAR OUT, BUT MAYBE NOT
ALL HOPE IS LOST FOR A WHITE CHRISTMAS. /FEWKES
AVIATION
12Z TAFS: HIGH PRESSURE IS BUILDING OVER THE AREA. IT 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 50% CHANCE FOR CIGS BELOW 1000 FT AGL AT GEG BETWEEN
THROUGH 1500. 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
IS CURRENTLY IN THE CASCADE VALLEYS ALREADY TONIGHT AND COULD
EXPAND ALONG THE COLUMBIA RIVER BTWN KEAT AND KOMK. WITH
INCREASING UPPER LEVEL CLOUDS IN THE AREA, RADIATIONAL COOLING
EFFECTS WILL BE WEAKENED AND LOWERING CHANCES OF IFR CONDITIONS
FOR MWH- EAT. 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 12Z TOMORROW. HOWEVER, GIVEN THE LATEST
TEMP/DEWPOINT SPREADS AND THIN MTN CIRRUS, FORECAST IS LEANING
TOWARD SOME RESTRICTIONS THROUGH 15Z ALONG THE WA/ID BORDER AND
INTO CENTRAL WA THROUGH 16Z. THE FORECAST COMES MODERATE TO LOW
CONFIDENCE AND ADDITIONAL AMENDMENTS ARE HIGHLY POSSIBLE. /JDC
-----------------------
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 41 33 43 32 44 34 / 10 20 0 0 50 70
COEUR D'ALENE 41 33 42 32 43 35 / 10 30 0 10 40 80
PULLMAN 43 35 46 35 45 32 / 0 10 0 0 50 70
LEWISTON 50 37 50 36 48 36 / 0 0 0 0 40 60
COLVILLE 38 29 39 29 40 32 / 20 40 10 20 50 80
SANDPOINT 37 32 40 31 42 32 / 10 50 10 20 40 90
KELLOGG 40 34 44 33 47 37 / 10 20 0 10 40 90
MOSES LAKE 42 33 42 33 44 32 / 10 10 0 0 60 30
WENATCHEE 37 32 38 32 40 32 / 10 20 0 0 60 20
OMAK 37 31 37 31 40 32 / 20 30 0 10 50 40
OTX WATCHES/WARNINGS/ADVISORIES
ID...NONE.
WA...NONE.
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