960
FXUS66 KOTX 291138
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
438 AM PDT TUE SEP 29 2026
KEY MESSAGES
- BREEZY WEST TO SOUTHWEST WINDS MAY RESULT IN PATCHY BLOWING
DUST NEAR RECENTLY PLOWED FIELDS TUESDAY AFTERNOON.
- MILD AND DRY PATTERN THIS WEEK, EXCEPT FOR RAIN NEAR THE
CASCADE CREST AND CHANCE OF RAIN NORTH IDAHO PANHANDLE ON
TUESDAY.
SYNOPSIS
MOISTURE OFF THE PACIFIC WILL BRING RAIN TO THE CASCADE CREST
AND NORTHEAST WASHINGTON AND NORTH IDAHO MOUNTAINS ON TUESDAY.
BREEZY WEST TO SOUTHWEST WINDS MAY RESULT IN PATCHY BLOWING DUST
NEAR RECENTLY PLOWED FIELDS TUESDAY AFTERNOON. TEMPERATURES
WILL BE NEAR NORMAL THROUGH THE MIDDLE OF THE WEEK AND THEN
TREND TO ABOVE NORMAL FOR THE END OF THE WEEK AND INTO THE
WEEKEND.
DISCUSSION
TODAY AND TONIGHT: AN ATMOSPHERIC RIVER AIMED AT VANCOUVER ISLAND
AND SOUTHERN BRITISH COLUMBIA WILL SAG SOUTH OVER NORTHERN
WASHINGTON INTO THE NORTH ID PANHANDLE THIS MORNING AND THEN
REMAIN NEARLY STATIONARY INTO THE AFTERNOON. STRONG WESTERLY FLOW
INTO THE CASCADE CREST COMBINED WITH THE INCREASE IN MOISTURE
WILL RESULT IN STEADY RAINS INTO THE WEST SLOPES OF THE CASCADES,
WITH SOME PRECIPITATION SPILLING OVER THE CREST INTO THE UPPER
REACHES OF THE METHOW VALLEY, LAKE CHELAN, AND LAKE WENATCHEE.
SOME DRY AIR INITIALLY COMBINED WITH A STRONG RAIN SHADOW EAST OF
THE CASCADES WILL RESULT IN MAINLY DRY CONDITIONS EXCEPT FOR AREAS
OF LIGHT RAIN IN THE MOUNTAINS OF NE WASHINGTON INTO THE ID
PANHANDLE. THIS SYSTEM WILL ALSO BRING IN A 130 KT UPPER JET INTO
SOUTHERN BRITISH COLUMBIA. THIS WILL KEEP OUR REGION ON THE
SOUTHERN, AND THUS STABLE SIDE OF THE JET WHICH WILL LIMIT OUR
MIXING POTENTIAL. YET AS 850MB WINDS INCREASE TO 20-30 KTS OUT OF
THE SOUTHWEST WINDY CONDITIONS WILL OCCUR IN THE MOUNTAINS, WITH
BREEZY WINDS ACROSS THE COLUMBIA BASIN, WENATCHEE AREA, WATERVILLE
PLATEAU, WEST PLAINS, AND PALOUSE. THESE WINDS ALSO HAVE THE
POTENTIAL TO PICK UP PATCHY BLOWING DUST NEAR RECENTLY PLOWED
FIELDS.
WEDNESDAY THROUGH MONDAY: MODELS ARE IN GOOD AGREEMENT THAT A
TRANSITION FROM WESTERLY FLOW TO A STRONG UPPER RIDGE WILL OCCUR
LATE IN THE WEEK BRINGING ABOUT A WARMING TREND. YET THERE ARE A
COUPLE OF WEAK WAVES IN THE WESTERLY FLOW THAT WILL TRACK THROUGH
WEDNESDAY AND THURSDAY. THE MOST LIKELY SCENARIO GIVEN THE LACK OF
LIFT IS FOR PASSING MID AND HIGH CLOUDS. YET THE NBM IS CARRYING A
20-30 PERCENT CHANCE OF LINGERING LIGHT RAIN WEDNESDAY MORNING IN
THE CENTRAL PANHANDLE MOUNTAINS, AND THEN ON THURSDAY A WEAK WAVE
BRINGING A 20-30 PERCENT CHANCE OF RAIN TO THE CASCADES AND A 5-10
PERCENT CHANCE ELSEWHERE. ONCE THE RIDGE STRENGTHENS FRIDAY INTO
SATURDAY CONFIDENCE INCREASES OF THE REGION GOING INTO A PROLONGED
WARM SPELL WITH DRY CONDITIONS. THE LATEST 6-10 AND 8-14 DAY
OUTLOOKS FROM THE CLIMATE PREDICTION CENTER ALSO SUPPORT THIS. JW
AVIATION
12Z TAFS: MID AND HIGH CLOUDS WILL BE ON THE INCREASE TONIGHT
DUE TO AN ARRIVAL OF MOISTEN LADEN WESTERLY 500MB JET. THE
STRONG WESTERLY FLOW ACROSS THE CASCADES TONIGHT INTO TUESDAY
WILL PROMOTE LEE WAVES AND FAVORABLE PATTERN FOR TURBULENCE WITH
GUSTY WINDS SURFACING IN THE LOWLANDS BY TUESDAY AFTERNOON. A
BULK OF THE RAIN WILL BE INTERCEPTED BY THE CASCADE CREST
LEADING TO WIDESPREAD MTN OBSCURATIONS, LIGHTER RAIN WITH HIGHER
CEILINGS WILL IMPACT FAR NE WA AND NORTH IDAHO. AFTER 09Z, HREF
SUGGEST INCREASED PROBABILITIES FOR MVFR CIGS ACROSS SOUTHERN
SHOSHONE COUNTY WITH A 30% CHANCE FOR CEILINGS BELOW 4K FT AGL.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: HIGH CONFIDENCE
FOR VFR CONDITIONS AND BREEZY WINDS AT ALL TAF SITES TODAY.
MODERATE TO HIGH CONFIDENCE FOR WINDS TO REMAIN STEADY THROUGH
THE EVENING AND OVERNIGHT HOURS WITH LOWER CONFIDENCE FOR
CONTINUED GUSTS. THERE IS A 10% CHANCE FOR THE MVFR CIGS IN
SHOSHONE COUNTY TO EXPAND TOWARD KPUW 11-17Z BUT THIS COMES WITH
LOW CONFIDENCE. /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 66 46 67 44 68 46 / 20 10 0 0 10 10
COEUR D'ALENE 62 49 65 43 66 45 / 20 10 10 0 10 10
PULLMAN 66 47 65 42 68 45 / 0 10 0 0 0 0
LEWISTON 74 53 70 47 73 51 / 0 10 0 0 0 0
COLVILLE 65 38 66 36 68 38 / 10 10 0 0 0 10
SANDPOINT 61 43 64 40 65 42 / 30 20 10 0 10 10
KELLOGG 60 48 62 44 65 47 / 10 30 20 0 10 10
MOSES LAKE 72 45 70 44 71 45 / 10 10 0 0 0 0
WENATCHEE 69 50 68 52 69 53 / 20 10 0 0 10 10
OMAK 66 41 68 42 69 43 / 10 10 0 0 0 0
OTX WATCHES/WARNINGS/ADVISORIES
WA...NONE.
ID...NONE.
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