805
FXUS66 KOTX 130837
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
137 AM PDT FRI MAR 13 2026
KEY MESSAGES
- HEAVY RAIN OVER THE PALOUSE INTO LEWISTON-CLARKSTON VALLEY AND
CAMAS PRAIRIE WILL INCREASE THE RISK OF SMALL STREAM FLOODING.
- POTENTIAL FOR HEAVY WET SNOW POSSIBLE IN THE VALLEYS OF
NORTHEAST WASHINGTON INTO THE NORTHERN PANHANDLE FOR FRIDAY
MORNING. THIS MAY LEAD TO IMPACTS TO THE FRIDAY MORNING
COMMUTE.
- MODERATE TO HEAVY MOUNTAIN SNOW THIS WEEK OVER THE CASCADES
AND NORTH IDAHO MOUNTAIN PASSES.
SYNOPSIS
A WET WEATHER SYSTEM WILL BE SITUATED OVER THE INLAND NORTHWEST
THROUGH FRIDAY. MODERATE TO HEAVY PRECIPITATION WITH RAIN AND A
MIX OF RAIN AND SNOW IN THE VALLEYS. RAIN OVER THE PALOUSE INTO
THE SOUTHERN IDAHO PANHANDLE WILL LEAD TO RISES ON RIVERS AND
SMALL STREAMS. A TRANSITION TO SNOW FOR NORTHERN VALLEYS IN
NORTHEAST WASHINGTON INTO THE NORTHERN PANHANDLE MAY LEAD TO
TRAVEL IMPACTS IN THE VALLEYS FRIDAY MORNING. DRIER AND BREEZY
OVER THE WEEKEND AND WARMING ABOVE NORMAL NEXT WEEK.
DISCUSSION
FRIDAY: NOW THAT THE WINDS HAVE SUBSIDED, WEATHER IMPACTS CONTINUE
ACROSS THE INLAND NW THOUGH THE FOCUS HAS SHIFTED TO A MIX OF
WINTER WEATHER AND HYDROLOGY. YESTERDAY'S COLD FRONT USHERED IN
COOLER AIR INTO THE REGION. THE FRONTAL BOUNDARY STALLED OVER
NORTHERN OREGON AND IS NOW LIFTING BACK NORTHWARD WITH A PLUME
OF SUBTROPICAL DRAPED ALONG IT. THIS IS RESULTING IN HEAVY SNOW
FOR THE CASCADE CREST AND CENTRAL PANHANDLE MOUNTAINS AND MIX OF
LIGHT TO MODERATE SNOW FOR THE LOWLANDS GENERALLY ALONG AND
NORTH OF A LINE FROM JUST SOUTH OF LAKE COEUR D ALENE TO
WENATCHEE. THIS WILL RESULT IN A SLICK FRIDAY MORNING COMMUTE
FOR FOLKS ACROSS NORTH IDAHO, NORTHEASTERN WA, AND NORTH-CENTRAL
WA INCLUDING THE HIGHWAY 2 CORRIDOR FROM WENATCHEE TO SPOKANE
AND I-90 ROUGHLY FROM TYLER TO LOOKOUT PASS. WINTER WEATHER
ADVISORIES HAVE BEEN ISSUED AND FOR MOST OF THESE AREAS WHERE
LOWLAND SNOWFALL AMOUNTS WILL BE ON THE ORDER OF 2+ INCHES. ONE
AREA THAT HAS HIGHER PROBABILITIES FOR 4+ INCHES WILL BE ACROSS
NORTHEASTERN WHITMAN-SOUTHERN SPOKANE-BENEWAH-KOOTENAI COUNTIES
WHERE THE COMBINATION OF FORCING/MOISTURE INFLUX WILL BE
MAXIMIZED AND RESULT IN SEVERAL HOURS OF MODERATE SNOW. SOME OF
THE HI-RES MODELS PRODUCE AS MUCH AS 7 OR MORE INCHES IN THESE
LOCAL AREAS. TEMPERATURES IN THIS EVENT ARE MARGINAL (32-34F)
WHICH MADE THIS EVENT A CHALLENGE TO FORECAST BUT GIVEN THE
INTENSITIES WE ARE OBSERVING, CONFIDENCE HAS INCREASED FOR
IMPACTS TO ROADS AND WE ARE ALREADY WITNESSING THIS ON SOME CAMS
SUCH AS SPANGLE, WA. GIVEN THE LOCATION OF THE STALLED FRONTAL
BOUNDARY CLOSER TO HIGHWAY 2, SNOW AMOUNTS GOING NORTHWARD INTO
THE NORTHERN MOUNTAIN VALLEYS WILL BE LIGHTER 1-3" THOUGH
IMPACTS ARE STILL ANTICIPATED FOR THE FRIDAY MORNING COMMUTE.
WITH THE CALENDAR READING MARCH 13TH AND MARGINAL TEMPERATURES,
IMPACTS TO TRAVEL THROUGH THE LOWLANDS WILL BE LIMITED TO THE
MORNING HOURS WITH MAINLY WET ROADS BY MIDDAY.
SOUTH OF THE FRONTAL BOUNDARY, TEMPERATURES ARE WARMER AND
PRECIPITATION IS MAINLY FALLING AS RAIN BELOW 3000 FEET.
MODERATE RAINS WILL FALL ACROSS THE LOWER PALOUSE, FOOTHILLS OF
THE BLUE MOUNTAINS, AND CAMAS PRAIRIE WITH INCREASING CONCERNS
FOR FLOODING AND ROCKSLIDES. AERIAL FLOOD WATCHES ARE IN EFFECT
TO ADDRESS THESE CONCERNS. POINT FLOOD WATCHES ARE ALSO OUT FOR
THE PALOUSE RIVER AT POTLATCH AND PARADISE CREEK IN MOSCOW. THE
NATIONAL WATER MODEL DOES INDICATE THE POTENTIAL FOR SEVERAL
SMALLER TRIBUTARIES TO REACH BANKFULL OR POTENTIALLY FLOOD.
RAINFALL AMOUNTS WILL BE ON THE ORDER OF 1-3 INCHES.
SATURDAY-SUNDAY: HIGH PRESSURE WILL AMPLIFY OFF THE COAST AND A
SHORTWAVE WILL DROP DOWN THE EASTERN FLANK THROUGH THE INLAND
NW. THIS WILL SHOVE THE SUBTROPICAL MOISTURE SOUTH OF THE REGION
BRINGING COOLING AND DRYING. A ROBUST SURFACE LOW WILL SPIN UP
IN SOUTHWESTERN MONTANA AND SLOWLY TRACK THROUGH WYOMING. THIS
WILL RESULT IN GUSTY NORTH TO NORTHWESTERLY WINDS ACROSS THE
INLAND NW OF 15-25 MPH WITH GUSTS AROUND 35 MPH. LOCALLY
STRONGER WIND GUSTS NEAR 40-45 MPH ARE EXPECTED OVER THE CAMAS
PRAIRIE, BLUE MOUNTAINS, WATERVILLE PLATEAU, AND ALONG THE EAST
SLOPES OF THE CASCADES. MAINLY RIDGELINES BUT A FEW OF THE
ALIGNED DRAINAGES WILL BE SUSCEPTIBLE TO GUSTS MIXING DOWN.
MOISTURE WRAPPING AROUND THE BACKSIDE OF THE LOW WILL BRING SNOW
SHOWERS THROUGH THE IDAHO PANHANDLE ON SATURDAY, OTHERWISE THE
START OF THE WEEKEND IS LOOKING DRY FOR THE INLAND NW. BY
SUNDAY, THE RIDGE BEGINS TO EXPAND INLAND USHERING A WARM FRONT
THROUGH THE REGION. MOISTURE DRAPED OVER THE RIDGE AND ALONG
THE WARM FRONT WILL BRING INCREASING CHANCES FOR LIGHT
PRECIPITATION MAINLY IN THE FORM OF LIGHT SNOW GIVEN THE
ANTECEDENT COOLING AND DRYING FROM SATURDAY. SNOW AMOUNTS WILL
BE VERY LIGHT WITH MINIMAL IMPACTS.
MONDAY-THURSDAY: THERE IS STRONG AGREEMENT AMONGST THE ENSEMBLE
CLUSTERS OF AN ABNORMALLY STRONG UPPER-LEVEL RIDGE SETTING UP
OVER THE WESTERN US THROUGH THIS PERIOD. THERE IS ALSO GOOD
AGREEMENT FOR AN ATMOSPHERIC RIVER TO RUN UP THE WESTERN FLANK
OF THE RIDGE. THERE IS HIGH CONFIDENCE FOR A WARMING TREND
ACROSS THE REGION. WHAT COMES WITH LOWER CONFIDENCE IS THE EXACT
AMPLIFICATION OF THE RIDGE ALONG THE CANADIAN BORDER. 70% OF
THE CLUSTERS INDICATE THE RIDGE WILL BE FLAT ENOUGH FOR THIS
MOISTURE TO STREAM ACROSS THE NORTHERN CASCADES DELIVERING
MODERATE QPF. 30% OF THE CLUSTERS HAVE A MORE AMPLIFIED RIDGE
AND NEARLY A THIRD OF THE QPF. THIS RAISES CONCERN FOR WARM AND
WET CONDITIONS ALONG THE CASCADE CREST NOT ONLY LEADING TO
INCREASED SNOW MELT OVER TIME BUT INCREASED RUNOFF INTO THE
HEADWATERS OF THE RIVER BASINS INTO THE EAST SLOPES INCLUDING
THE STEHEKIN RIVER. THIS WILL NEED TO BE MONITORED CLOSELY FOR
THE NEXT ROUND OF HYDROLOGY CONCERNS HEADING INTO NEXT WEEK.
TEMPERATURES IN THE LOWLANDS ARE FORECAST TO WARM INTO THE 60S
TUESDAY-THURSDAY. /SB
AVIATION
06Z TAFS: A MOISTURE LADEN FRONTAL BOUNDARY WITH AN INFLUX OF
SUBTROPICAL MOISTURE IS SLOWLY LIFTING NORTHWARD WITH WIDESPREAD
PRECIPITATION DEVELOPING. THIS HAS AND WILL CONTINUE TO RESULT
IN TOP DOWN MOISTENING WITH HIGH PROBABILITIES (70-80%) FOR
MVFR/IFR CONDITIONS. THE ANTECEDENT AIR MASS NORTH OF I-90 AND
PARTICULARLY ALONG HIGHWAY 2 NORTHWARD IS COLD ENOUGH FOR SNOW.
HI-RES MODELS HAVE INCREASED SNOW AMOUNTS FOR GEG-COE VARYING
FROM 2-4 INCHES HOWEVER THIS COMES WITH SURFACE TEMPERATURES OF
33-34F WHICH LEADS TO LOWER CONFIDENCE FOR ACCUMULATIONS ON
RUNWAYS. WHEN PRECIPITAITON INTENSITIES REACH MODERATE, SLUSHY
ACCUMULATIONS ARE EXPECTED EVEN WITH TEMPERATURES OF 33F AND
THERE IS MODERATE CONFIDENCE FOR THIS TO DEVELOP AT TIMES 9-14Z.
PRECIPITATION TYPE FAVORS MORE RAIN VS SNOW AT PUW THIS EVENING
WITH WINDS 1000-2000 FT AGL AROUND 30-35KTS UNTIL 11Z LEADING
TO MARGINAL LLWS. EXPECT THE BAND OF MOISTURE TO STALL OVER THE
INLAND NW THROUGH 22Z FRIDAY THEN BEGIN TO SAG BACK SOUTH 22-06Z
WITH MAINLY EAT, MWH, OMK, AND COLVILLE EXPERIENCING DRIER
CONDITIONS.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: HIGH CONFIDENCE
FOR IFR CONDITIONS TO DEVELOP WITH PRECIPITATION TONIGHT
KEAT/KGEG/KSFF/KCOE/KPUW AIRPORT TERMINALS. CONFIDENCE REMAINS
LOW FOR PRECIPITATION TYPE AT EAT/MWH. MODERATE CONFIDENCE FOR
WET SNOW ACCUM AT GEG/COE, LOW CONFIDENCE AT SFF/PUW. /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 42 30 43 24 42 34 / 90 60 40 0 10 50
COEUR D'ALENE 41 31 43 21 41 32 / 100 80 70 10 20 70
PULLMAN 37 31 40 25 41 34 / 100 100 80 20 10 60
LEWISTON 47 38 49 29 47 39 / 100 100 80 20 0 50
COLVILLE 45 25 45 21 43 29 / 70 30 30 0 30 60
SANDPOINT 40 29 40 20 39 31 / 90 60 80 20 30 70
KELLOGG 38 32 37 18 39 32 / 100 90 90 40 30 70
MOSES LAKE 49 30 48 28 46 34 / 80 50 10 0 10 20
WENATCHEE 46 29 43 28 43 34 / 90 50 10 0 20 40
OMAK 47 27 47 26 43 33 / 60 10 10 0 20 40
OTX WATCHES/WARNINGS/ADVISORIES
WA...WINTER WEATHER ADVISORY UNTIL NOON PDT TODAY FOR SPOKANE AREA-
UPPER COLUMBIA BASIN-WATERVILLE PLATEAU.
FLOOD WATCH THROUGH SATURDAY AFTERNOON FOR LOWER GARFIELD AND
ASOTIN COUNTIES-NORTHEAST BLUE MOUNTAINS-WASHINGTON
PALOUSE.
WINTER WEATHER ADVISORY UNTIL 11 AM PDT THIS MORNING FOR
CENTRAL CHELAN COUNTY-WASHINGTON PALOUSE.
WINTER STORM WARNING UNTIL 5 AM PDT SATURDAY FOR WESTERN
CHELAN COUNTY.
ID...WINTER WEATHER ADVISORY UNTIL NOON PDT TODAY FOR COEUR D'ALENE
AREA.
FLOOD WATCH THROUGH SATURDAY AFTERNOON FOR CENTRAL PANHANDLE
MOUNTAINS-IDAHO PALOUSE-LEWIS AND SOUTHERN NEZ PERCE
COUNTIES-LEWISTON AREA.
WINTER WEATHER ADVISORY UNTIL 11 AM PDT THIS MORNING FOR IDAHO
PALOUSE.
WINTER STORM WARNING UNTIL 11 AM PDT SATURDAY FOR CENTRAL
PANHANDLE MOUNTAINS.
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