955
FXUS66 KOTX 250615
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1115 PM PDT TUE MAR 24 2026
KEY MESSAGES
- CASCADE PASS SNOW: WINTRY TRAVEL CONDITIONS DEVELOP TONIGHT
THROUGH WEDNESDAY OVER THE CASCADES AS SNOW LEVELS DROP TO
BELOW PASS LEVELS.
- GUSTY WINDS: WINDS WILL BE BREEZY THROUGH WEDNESDAY WITH
SOUTHWESTERLY GUSTS 25 TO 40 MPH.
- HYDROLOGY: THE STEHEKIN RIVER AT STEHEKIN IS FORECAST TO
REMAIN ABOVE ITS ACTION STAGE (19.5 FT) FOR THE NEXT WEEK.
OTHER AREA RIVERS WILL STAY ELEVATED BUT WILL REMAIN BELOW
ACTION STAGE.
SYNOPSIS
AN INCOMING LOW PRESSURE SYSTEM IS USHERING IN A PLUME OF
MOISTURE OFF OF THE PACIFIC, BRINGING WIDESPREAD PRECIPITATION
AND GUSTY SOUTHWESTERLY WINDS. A TRAILING COLD FRONT PUSHING
THROUGH THIS EVENING WILL DROP SNOW LEVELS BELOW MOUNTAIN
PASSES, RESULTING IN WINTRY TRAVEL CONDITIONS OVER THE CASCADES
TONIGHT THROUGH WEDNESDAY. HIGH PRESSURE RETURNS THURSDAY
THROUGH THE WEEKEND MAKING FOR A DRIER AND WARMER END TO THE
WEEK.
DISCUSSION
TODAY AND WEDNESDAY: PRECIPITABLE WATER VALUES ARE CURRENTLY
BETWEEN 200 AND 250 PERCENT OF NORMAL ACROSS THE INLAND
NORTHWEST COURTESY OF AN INCOMING LOW PRESSURE SYSTEM DIRECTING
AN ATMOSPHERIC RIVER AT THE REGION. WIDESPREAD RAINFALL IS BEING
OBSERVED WITH POCKETS OF SNOW IN THE VALLEYS ALONG THE EAST
SLOPES OF THE CASCADES. PRECIPITATION WILL CONTINUE INTO THIS
EVENING REGIONWIDE, THEN HEADING INTO THE OVERNIGHT HOURS A
COLD FRONT PASSAGE WILL DROP SNOW LEVELS FROM WEST TO EAST AND
USHER IN DRIER, MORE WESTERLY FLOW, PUTTING AN END TO
PRECIPITATION EVERYWHERE BUT THE CASCADES, NORTHERN WA
MOUNTAINS, AND ID PANHANDLE MOUNTAINS.
BETWEEN TONIGHT AND WEDNESDAY NIGHT, THE ID PANHANDLE LOWLANDS
HAVE A 50 TO 80 PERCENT CHANCE OF SEEING AT LEAST 0.50 INCHES OF
LIQUID, WHILE THESE CHANCES JUMP UP TO NEAR 100 PERCENT FOR
HIGHER ELEVATIONS. FOR EXTREME EASTERN WA (EAST OF A LINE FROM
METALINE FALLS TO PULLMAN) THERE IS A 30 TO 50 PERCENT CHANCE
FOR AT LEAST 0.50 INCHES OF PRECIP.
LOOKING AT SNOW ACCUMULATION, SNOW LEVELS WILL DROP TO AROUND
2000 FEET BEHIND THE COLD FRONT PASSAGE TONIGHT, TRANSITIONING
PRECIP TYPE AT MOUNTAIN PASSES FROM RAIN TO SNOW. SNOW WILL
CONTINUE OVER THE PASSES THROUGH WEDNESDAY AND INTO EARLY
THURSDAY, RESULTING IN WINTRY TRAVEL CONDITIONS AT TIMES.
THE 10TH PERCENTILE (LOW END) SNOW AMOUNT FORECAST FOR STEVENS
PASS IS 3 INCHES OVER THE COURSE OF THE EVENT, WHILE THE 90TH
PERCENTILE (HIGH END) AMOUNT IS 13 INCHES. HOW MUCH SNOW STEVENS
PASS ENDS UP GETTING WILL DEPEND LARGELY ON WHERE THE PUGET
SOUND CONVERGENCE ZONE SETS UP WEDNESDAY AFTERNOON. IF THE
CONVERGENCE ZONE SETS UP DIRECTLY OVER THE PASS, SNOW AMOUNTS
WILL LIKELY BE ON THE HIGH END OF THAT RANGE, WHILE IF THE
CONVERGENCE ZONE IS SLIGHTLY NORTH OR SOUTH OF THE PASS, SNOW
AMOUNTS WILL BE LOWER. LOOKOUT AND SHERMAN PASSES WILL SEE MUCH
LIGHTER ACCUMULATIONS OF AROUND AN INCH. SOME SPOTS IN THE
CASCADE VALLEYS INCLUDING MAZAMA AND WINTHROP HAVE SEEN A COUPLE
INCHES OF SNOW FALL SO FAR TODAY, BUT SNOW IN THESE VALLEYS
WILL TAPER OFF FOLLOWING THE COLD FRONT PASSAGE.
IN ADDITION TO SNOW, THIS SYSTEM WILL BRING GUSTY WINDS OUT OF
THE SOUTHWEST BETWEEN 25-40 MPH THIS AFTERNOON THROUGH
WEDNESDAY. HIGHEST GUSTS ARE FORECAST ACROSS THE COLUMBIA BASIN
AND OVER THE SPOKANE/PALOUSE AREAS. ONE LAST THING TO KEEP AN
EYE ON FOR WEDNESDAY AFTERNOON WILL BE SOME WEAK POST-FRONTAL
INSTABILITY. THE HREF DEPICTS 50-100 J/KG OF SURFACE CAPE
WEDNESDAY AFTERNOON OVER THE CASCADE CREST, NORTHERN MOUNTAINS,
AND ID PANHANDLE WHICH MAY BE ENOUGH TO TRIGGER A ROGUE
LIGHTNING STRIKE OR TWO.
THURSDAY THROUGH MONDAY: THE PATTERN TURNS DRIER AND WARMER
HEADING INTO NEXT WEEKEND AS A RIDGE OF HIGH PRESSURE BUILDS
IN BEHIND THE EXITING LOW. AFTER THURSDAY MORNING, PRECIPITATION
CHANCES DROP TO NEAR ZERO THROUGH SUNDAY. AFTERNOON HIGHS WILL
CLIMB INTO THE 50S AND 60S, THOUGH MOSTLY CLEAR SKIES WILL ALLOW
OVERNIGHT LOWS TO DIP INTO THE 20S AND 30S. ENSEMBLES HINT AT A
RIDGE BREAKDOWN EARLY NEXT WEEK, BUT FOR NOW, THE WEEKEND LOOKS
DRY AND CALM. /FEWKES
AVIATION
06Z TAFS: CURRENT SATELLITE IS SHOWING GENERALLY CLEAR SKIES
FOR MOST OF THE REGION EXCLUDING KGEG/KSFF/KCOE. LOW LEVEL
STRATUS IS STILL IN THE AREA OF THE SITES BUT NOT IMPACTING THE
AIRFIELD TAF. LINGERING LOWER LEVEL MOISTURE WILL KEEP THE
THREAT OF MVFR CONDITIONS GOING INTO WEDNESDAY MORNING. BREEZY
WINDS ARE EXPECTED, BUT IT HAS NOT BEEN CONSISTENT BUT SOME
STRONGER WINDS REMAIN ALOFT. TOMORROW LOOKS DRIER WITH LARGELY
VFR CONDITIONS AT MOST TAF SITES, ESPECIALLY AFTER 15Z. SOME
AFTERNOON SHOWERS ARE IN THE FORECAST BUT THE RISK AT TAF SITE
IS LIMITED. IT WILL REMAIN BREEZY THROUGH 03Z.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
LOW TO MODERATE CONFIDENCE FOR MVFR CONDITIONS THROUGH 19Z AT
GEG/SFF/COE/PUW WITH A 60% CHANCE FOR CEILINGS BELOW 3 KFT AGL.
-----------------------
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 38 52 28 47 28 55 / 80 10 20 0 0 0
COEUR D'ALENE 40 52 28 47 27 57 / 100 10 40 0 0 0
PULLMAN 41 49 28 44 29 56 / 100 40 20 0 0 0
LEWISTON 47 56 33 51 31 60 / 100 50 20 0 0 0
COLVILLE 35 54 27 50 26 57 / 60 20 30 0 0 0
SANDPOINT 39 50 29 46 27 52 / 100 30 60 20 0 0
KELLOGG 41 48 28 43 28 56 / 100 40 60 20 0 0
MOSES LAKE 36 57 30 53 29 60 / 30 10 10 0 0 0
WENATCHEE 38 53 31 51 32 55 / 10 20 10 0 0 0
OMAK 37 55 29 52 31 57 / 10 20 10 0 0 0
OTX WATCHES/WARNINGS/ADVISORIES
WA...WINTER WEATHER ADVISORY UNTIL 5 AM PDT THURSDAY FOR WESTERN
CHELAN COUNTY-WESTERN OKANOGAN COUNTY.
ID...NONE.
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