344
FXUS66 KOTX 141748
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1048 AM PDT SUN SEP 14 2025
KEY MESSAGES
- COOLER TODAY WITH WIDESPREAD RAIN. HIGHEST TOTALS ACROSS
SOUTHEAST WASHINGTON AND SOUTHERN IDAHO PANHANDLE. ISOLATED
AFTERNOON THUNDERSTORMS.
- WARM AND DRY TUESDAY AND WEDNESDAY.
SYNOPSIS
A WEATHER SYSTEM ARRIVES TODAY BRINGING COOLER TEMPERATURES,
BREEZY WEST TO SOUTHWEST WINDS, AND WIDESPREAD PRECIPITAITON.
HIGH PRESSURE REBUILDS TUESDAY AND WEDNESDAY WITH A BRIEF RETURN
OF WARMER AND DRIER CONDITIONS.
DISCUSSION
SUNDAY AND MONDAY: AN UPPER-LEVEL TROUGH AND AN ASSOCIATED OLD FRONT
WILL MOVE ACROSS THE INLAND NORTHWEST TODAY. WATER VAPOR IMAGERY AND
MODEL CONSENSUS DEPICT THE TROUGH TO BECOME NEGATIVELY TILTED AS IT
TRACKS ONSHORE. DEEP SOUTHERLY FLOW AHEAD OF THE SYSTEM IS ADVECTING
AMPLE MOISTURE INTO THE INLAND NORTHWEST, WITH PRECIPITABLE WATER
VALUES EXCEEDING 0.80 INCHES SUNDAY MORNING. MODELS HAVE COME INTO
MUCH BETTER AGREEMENT FOR THE BASE OF THE TROUGH TO TRAVEL ACROSS
NORTHERN OREGON, PROVIDING SUFFICIENT LIFT FOR WIDESPREAD
PRECIPITATION THIS MORNING INTO THE EARLY AFTERNOON. THIS WILL
TRANSITION TO SCATTERED CONVECTIVE SHOWERS THIS AFTERNOON AND
EVENING, WITH SHOWERS LINGERING OVER THE IDAHO PANHANDLE INTO MONDAY
MORNING.
WHILE MODELS HAVE TRENDED WETTER, CONSIDERABLE SPREAD REMAINS IN
NATIONAL BLEND OF MODEL’S (NBM) QPF. THE 25TH-75TH PERCENTILE RANGE
IS 0.05-0.50 INCHES FOR NORTHEAST WASHINGTON AND NORTH IDAHO. LOWER
TOTALS, FROM 0-0.15 INCHES, ARE EXPECTED IN THE LEE OF THE CASCADES
DUE TO DOWNSLOPING EFFECTS OFF THE CASCADES. THE HIGHEST TOTALS ARE
FAVORED ACROSS SOUTHEAST WASHINGTON AND THE SOUTHERN IDAHO
PANHANDLE, CLOSER TO THE BASE OF THE TROUGH, WITH A 25TH-75TH
PERCENTILE RANGE OF 0.10-0.90 INCHES. CAMS INDICATE THE GREATEST
INSTABILITY AND STEEPEST LAPSE RATES WILL ALSO BE FOCUSED IN THESE
SOUTHERN AREAS, WITH THE NBM GIVING A 15-20% CHANCE OF
THUNDERSTORMS THIS AFTERNOON. INSTABILITY DECREASES FARTHER
NORTHWARD, WITH LESS CONFIDENCE (5-15% CHANCE) IN THUNDERSTORMS
SUNDAY AFTERNOON.
SOUTHWESTERLY WINDS WILL INCREASE WITH THE MORNING PRECIPITATION,
WITH SUSTAINED SPEEDS OF 10-20 MPH AND GUSTS OF 20-30 MPH.
MONDAY NIGHT THROUGH FRIDAY: HIGH CONFIDENCE EXISTS IN AN
UPPER-LEVEL RIDGE BUILDING OVER THE REGION LATE MONDAY, BECOMING
CENTERED OVER THE AREA TUESDAY AND PERSISTING THROUGH
WEDNESDAY. A THERMALLY- INDUCED SURFACE PRESSURE TROUGH IS
EXPECTED TO DEVELOP WEST OF THE CASCADES, SUPPORTING BREEZY
EASTERLY WINDS ACROSS CENTRAL WASHINGTON INTO TUESDAY. THE
THERMAL TROUGH WILL SHIFT EAST OF THE CASCADES BY WEDNESDAY,
ALLOWING WINDS TO RETURN TO A WEST/SOUTHWESTERLY DIRECTION.
FORECAST CONFIDENCE DECREASES LATE IN THE WEEK. ENSEMBLES AGREE ON
ANOTHER UPPER-LEVEL TROUGH AFFECTING THE REGION BUT SHOW SIGNIFICANT
SPREAD IN ITS TRACK AND STRENGTH. THIS WILL BE THE NEXT PERIOD TO
MONITOR FOR BREEZY WINDS AS THE RIDGE BREAKS DOWN, HOWEVER, FORECAST
UNCERTAINTY REMAINS TOO HIGH FOR SPECIFICS AT THIS TIME. /VMT
AVIATION
18Z TAFS: RADAR SHOWS RAIN WITHIN THE HOUR TO
GEG/SFF/COE/PUW/LWS, WITH GOOD ENOUGH CONFIDENCE TO HAVE THE
RAIN BE IN PREVAILING FOR ALL BUT LWS. FOR GEG/SFF/COE/PUW,
THERE IS MODERATE CONFIDENCE THAT SHOWERS WILL BRING CEILINGS
DOWN TO MVFR FROM ~19-24Z, WITH MVFR ENDING EARLIER FOR PUW.
WINDS HAVE ALREADY PICKED UP FROM THE SOUTHWEST WITH SUSTAINED
WINDS OF 10KTS OR MORE AT GEG/SFF/COE, AND THE POTENTIAL TO GUST
TO 20KTS THROUGHOUT THE AFTERNOON. THERE IS A 10-20 PERCENT
CHANCE FOR THUNDERSTORMS IN FAR SOUTHEAST WASHINGTON AND THE
SOUTHERN IDAHO PANHANDLE THAT INCLUDES PUW/LWS, BUT
PROBABILITIES ARE TOO LOW TO INCLUDE THEM IN TAFS AT THIS TIME.
BY 18Z TOMORROW, RAIN WILL HAVE ENDED FOR THE TAF SITES.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS:
MODERATE CONFIDENCE IN MVFR CONDITIONS WITH RAIN AT
KGEG/KSFF/KCOE AND LOW CONFIDENCE AT KPUW WITH RAIN. LOW
CONFIDENCE IN THUNDERSTORMS AT PUW/LWS SUNDAY AFTERNOON AND
EVENING.
-----------------------
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:/WEATHER.GOV/OTX/AVNDASHBOARD
PRELIMINARY POINT TEMPS/POPS
SPOKANE 68 50 72 50 82 52 / 80 40 10 0 0 0
COEUR D'ALENE 69 52 69 50 82 54 / 70 60 20 0 0 0
PULLMAN 64 46 67 45 78 49 / 80 60 10 0 0 0
LEWISTON 72 55 74 53 83 57 / 80 60 10 0 0 0
COLVILLE 72 43 74 41 82 42 / 70 50 20 0 0 0
SANDPOINT 70 47 67 46 80 48 / 60 70 50 0 0 0
KELLOGG 68 51 63 50 80 55 / 60 70 40 0 0 0
MOSES LAKE 73 47 75 49 83 50 / 70 20 0 0 0 0
WENATCHEE 73 52 77 56 81 58 / 60 20 0 0 0 0
OMAK 73 50 80 53 84 55 / 60 40 0 0 0 0
OTX WATCHES/WARNINGS/ADVISORIES
WA...AIR QUALITY ALERT UNTIL NOON PDT MONDAY FOR CENTRAL CHELAN
COUNTY-NORTHEAST MOUNTAINS-OKANOGAN HIGHLANDS-WENATCHEE
AREA-WESTERN CHELAN COUNTY.
ID...NONE.
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