775
FXUS66 KOTX 170522
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
922 PM PST MON DEC 16 2024
SYNOPSIS
A WETTER WEATHER SYSTEM IS EXPECTED TUESDAY INTO TUESDAY NIGHT
WITH RISING SNOW LEVELS. SNOW WILL MAINLY ACCUMULATE OVER HIGH
MOUNTAINS AND IN NORTH-CENTRAL WASHINGTON INCLUDING THE EASTERN
CASCADE VALLEYS. THIS WET SYSTEM WILL BE FOLLOWED BY BREEZY WINDS
WEDNESDAY AFTERNOON. THE REST OF THE WEEK WILL FEATURE MILD
TEMPERATURES AND INTERMITTENT LIGHT PRECIPITATION PRIMARILY
CONFINED TO THE NORTHERN MOUNTAINS.
DISCUSSION
TODAY THROUGH WEDNESDAY AFTERNOON: A WEAK VORT MAX HAS KEPT
PRECIPITATION ONGOING IN EXTREME EASTERN WASHINGTON AND NORTH
IDAHO THIS AFTERNOON. DESPITE LIGHT SNOW ONGOING, ROAD
TEMPERATURES HAVE WARMED UP ENOUGH TO WHERE EVERY ROAD LOOKS JUST
WET ON WEBCAMS ALONG WITH SURFACE TEMPERATURES AROUND 32-34
DEGREES. I-90 AT LOOKOUT PASS REMAINS THE EXCEPTION THIS AFTERNOON
WITH SNOW PERSISTING AND TEMPERATURES AROUND 23-25 DEGREES. WITH
THAT IN MIND, I TOOK DOWN ALL THE WINTER HIGHLIGHTS EXCEPT FOR THE
CENTRAL PANHANDLE MOUNTAINS. SNOW SHOWERS WILL CONTINUE OVERNIGHT
BRINGING PERIODIC WINTRY CONDITIONS TO LOOKOUT PASS. TEMPERATURES
TONIGHT WILL FALL INTO THE MID 20S TO THE LOW 30S. SOME POCKETS
OF CLEARING GIVE THE METHOW VALLEY A CHANCE TO SEE SINGLE DIGIT
LOWS YET AGAIN.
THE NEXT SYSTEM WILL SPREAD LIGHT TO MODERATE SNOW ACROSS THE
REGION TONIGHT INTO TOMORROW MORNING IN CENTRAL WASHINGTON. NBM
GUIDANCE CONTINUES TO STRUGGLE THIS YEAR IN THE CASCADE VALLEYS
WITH LOW LEVEL TEMPERATURES WARMING TOO FAST. 850 MB TEMPERATURES
WILL RANGE FROM -2 TO -5C THROUGH WEDNESDAY AFTERNOON. SURFACE
TEMPERATURES WILL RUN AROUND 28-34 DEGREES FROM LEAVENWORTH TO
HARTLINE ON US-2 AND WENATCHEE TO OROVILLE ON HIGHWAY 97 DURING
MUCH OF THE DAY TUESDAY. ALONG THE COLUMBIA RIVER, SNOW AMOUNTS
WILL RANGE FROM 0.5-3 INCHES FROM TUESDAY MORNING TO TUESDAY
NIGHT. AT ELEVATIONS ABOVE 1250 FEET, SNOW AMOUNTS WILL RANGE FROM
3 TO 8 INCHES. AS THE WARM TONGUE INFILTRATES THE REGION AFTER
DARK TOMORROW AND 850 MB TEMPERATURE WARM TO 1 TO 4C, SNOW WILL
CHANGE OVER TO FREEZING RAIN IN CENTRAL AND WESTERN CHELAN COUNTY
AND THE WATERVILLE PLATEAU. FROM STEVENS PASS TO LEAVENWORTH,
THERE IS A 60% CHANCE OF 0.2” OR MORE OF FREEZING RAIN. LUCKILY,
THE FREEZING RAIN WILL BE FALLING ON SNOW, WHICH POSES A LESSER
THREAT THAN PURE FREEZING RAIN. AFTER SUNRISE WEDNESDAY, MOST
LOCATIONS WILL CHANGE OVER TO RAIN IF THEY HAVE NOT ALREADY AS
UPPER AIR TEMPERATURES WARM EVEN MORE. HIGH TEMPERATURES WEDNESDAY
WILL REACH INTO THE 40S REGIONWIDE. /DB
WEDNESDAY NIGHT THROUGH SUNDAY: PRECIPITATION CHANCES WILL RECEDE
INTO THE CASCADES AND HIGHER TERRAIN OF NORTHERN WA AND NORTH ID
WEDNESDAY NIGHT. LOWLANDS WILL SEE MAINLY DRY CONDITIONS FOR THE
REMAINDER OF THE WORKWEEK WITH DAYTIME HIGH TEMPERATURES IN THE MID
30S TO MID 40S AND OVERNIGHT LOWS IN THE 20S AND 30S. MORE
WIDESPREAD PRECIPITATION LOOKS TO RETURN OVER THE WEEKEND AND INTO
EARLY NEXT WEEK, LARGELY IN THE FORM OF RAIN FOR LOWER ELEVATIONS.
MODELS ARE SUGGESTING TEMPERATURES WILL TREND WARMER AS WE HEAD INTO
THE WEEKEND WITH HIGHS NEARING 50 FOR LEWISTON SATURDAY AND SUNDAY,
AND GUIDANCE IS NOT SHOWING ANY SIGNS OF THINGS COOLING DOWN THROUGH
AT LEAST THE START OF THE NEW YEAR. THINGS ARE NOT LOOKING GOOD FOR
A WHITE CHRISTMAS DAY, BUT TIME WILL TELL. UNCERTAINTY IS HIGH WHEN
FORECASTING THAT FAR OUT. /FEWKES
AVIATION
06Z TAFS: IFR TO LOW IFR CEILINGS PERSIST WITH MIST AND FOG OVER
THE BASIN INTO KGEG AND KPUW (70-100% CHANCE). LIGHT SNOW WILL
SPREAD ACROSS CENTRAL WASHINGTON AROUND 12-18Z TUE AND PICK UP IN
INTENSITY THROUGH TUESDAY MORNING. KEAT-KOMK-KS52 WILL SEE THE
GREATEST SNOW IMPACTS. PRECIPITATION WILL SPREAD EAST DURING THE
LATE MORNING AND EARLY AFTERNOON BEING PRIMARILY RAIN FOR MWH AND
EASTWARD.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: CONFIDENCE HAS
INCREASED FOR IFR CONDITIONS PERSISTING THROUGH THE PERIOD.
-----------------------
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 31 38 36 45 30 40 / 40 50 90 60 0 10
COEUR D'ALENE 31 37 34 44 30 40 / 60 40 90 70 10 10
PULLMAN 31 37 37 46 31 41 / 70 40 90 40 0 10
LEWISTON 35 45 41 53 34 45 / 60 40 70 30 0 10
COLVILLE 27 33 31 42 24 36 / 30 50 90 80 0 20
SANDPOINT 29 36 32 41 28 37 / 50 40 100 90 10 20
KELLOGG 31 37 34 41 31 42 / 60 30 90 70 10 20
MOSES LAKE 32 38 36 46 29 40 / 30 80 80 40 0 10
WENATCHEE 31 34 34 42 29 37 / 20 90 80 50 10 20
OMAK 28 33 32 42 26 36 / 0 80 90 60 0 20
OTX WATCHES/WARNINGS/ADVISORIES
ID...WINTER WEATHER ADVISORY UNTIL 7 AM PST TUESDAY FOR CENTRAL
PANHANDLE MOUNTAINS.
WA...WINTER WEATHER ADVISORY FROM 10 AM TUESDAY TO 4 AM PST WEDNESDAY
FOR OKANOGAN HIGHLANDS-OKANOGAN VALLEY-WESTERN OKANOGAN
COUNTY.
WINTER WEATHER ADVISORY FROM 4 AM TUESDAY TO 4 AM PST WEDNESDAY
FOR CENTRAL CHELAN COUNTY-WATERVILLE PLATEAU-WENATCHEE AREA-
WESTERN CHELAN COUNTY.
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