721
FXUS66 KOTX 220742
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1242 AM PDT FRI AUG 22 2025
KEY MESSAGES
- WARM AND DRY THROUGH THE WEEKEND AND INTO NEXT WEEK WITH MUCH
OF CENTRAL WA AND THE L-C VALLEY IN AREAS OF MAJOR HEATRISK
WITH ISOLATED AREAS OF EXTREME HEATRISK.
- BREEZY NORTH TO NORTHEAST WINDS FRIDAY.
SYNOPSIS
TEMPERATURES WILL CONTINUE TO WARM THROUGH THE WEEKEND AND REMAIN
WELL ABOVE NORMAL THROUGH MID WEEK. WIDESPREAD HIGH TEMPERATURES
IN THE MID 90S TO LOW 100S ARE FORECAST SATURDAY THROUGH WEDNESDAY
WITH MODERATE TO MAJOR HEATRISK FOR FAR EASTERN WASHINGTON AND
NORTH IDAHO. MAJOR TO EXTREME HEATRISK IS EXPECTED FOR CENTRAL
WASHINGTON.
DISCUSSION
A VERY FAVORABLE SYNOPTIC SETUP IS DEVELOPING FOR A
SIGNIFICANT LATE SEASON HEATWAVE FOR THE PACIFIC NORTHWEST. THE
UPPER LEVEL RIDGE AXIS CURRENTLY IS POSITIONED OVER CENTRAL WA,
OR, AND BRITISH COLUMBIA SANDWICHED BETWEEN TWO TROFS. OVER THE
NEXT 24 HOURS, THE RIDGE WILL AMPLIFY IN RESPONSE TO THE 4-CORNERS
HIGH SHIFTING WEST. AT THE SURFACE, HIGH PRESSURE IS
STRENGTHENING OVER THE NORTHERN ROCKIES WHICH WILL HAVE AN
IMMEDIATE IMPACT ON OUR WEATHER PATTERN BEGINNING FRIDAY MORNING.
OVER THE NEXT FEW DAYS, THE SURFACE HIGH PRESSURE WEAKENS BUT THE
RIDGE CONTINUES TO AMPLIFY OVER THE PACNW BRINGING RECORD
TEMPERATURES ALONG COASTAL AREAS AND NEAR RECORD TEMPERATURES TO
THE INTERIOR.
WITH STRENGTHENING HIGH PRESSURE OVER THE NORTHERN ROCKIES, A
SURFACE THERMAL LOW WILL DEVELOP FRIDAY OVER CENTRAL WA AND OR.
THIS IS GOING TO PROMOTE INCREASING WINDS FROM THE NORTHEAST
THROUGH FRIDAY MORNING HOURS...BECOMING GUSTY THROUGH N-S VALLEYS
AND ACROSS THE WATERVILLE PLATEAU. WINDS ARE EXPECTED TO
SUBSIDE DURING THE LATE AFTERNOON HOURS AS THE PRESSURE/THERMAL
GRADIENT RELAXES BUT THE NORTHEAST COMPONENT TO THE WIND WILL
REMAIN THROUGHOUT THE HEATWAVE.
GIVEN THE INCREASED FIRE ACTIVITY FROM A FEW LARGE WESTERN MONTANA
WILDFIRES, THE NORTHEAST WIND COULD ALSO INCREASE THE SMOKE ACROSS
NORTH IDAHO AND EASTERN WASHINGTON THROUGH THE WEEKEND. THE SMOKE
MODELS HAVE NOT PICKED UP ON THE NEW ACTIVITY SO WE DON'T HAVE A
GOOD FEEL FOR HOW MUCH SMOKE COULD INVADE THE INLAND NORTHWEST BUT
I THINK IT'S A SAFE BET WE'LL BE EXPERIENCING HAZY SKIES AT THE
VERY LEAST BY THE WEEKEND, WITH THE POSSIBILITY OF AIR QUALITY
IMPACTS DEPENDING ON HOW ACTIVE THOSE FIRES REMAIN.
THROUGH THE WEEKEND, TEMPERATURES INCREASE RESULTING IN MAJOR TO
EXTREME HEATRISK FOR MANY AREAS PROMPTING THE EXCESSIVE HEAT
WATCH. SINCE THE HEATWAVE EXTENDS FOR SEVERAL DAYS, OVERNIGHT LOWS
WILL HAVE A HARDER AND HARDER TIME RECOVERING RESULTING IN WARMER
OVERNIGHT LOWS. WHILE VERY FEW RECORD HIGH TEMPERATURES WILL BE
BROKEN, THE EXCESSIVE HEAT WATCH IS NECESSARY TO CAPTURE THE
SIGNIFICANCE OF POOR RECOVERIES NIGHT AFTER NIGHT. OVERALL,
TEMPERATURES ARE ABOUT 15 DEGF ABOVE NORMAL FOR THIS TIME OF
YEAR.
A USEFUL TOOL TO SEE HOW UNUSUAL OR EXTREME A WEATHER EVENT IS
THE EFI (ECMWF EXTREME FORECAST INDEX). THIS TOOL HIGHLIGHTS
COASTAL AREAS THROUGH THE WEEKEND AND THEN THE SHADED REGION OF
UNUSUAL TEMPERATURES MIGRATES OVER THE CASCADES SUNDAY AND THEN
FARTHER INLAND EARLY NEXT WEEK. A FEW INTERESTING PROBABILISTIC
STATS FOR THIS HEATWAVE...
- 49% CHANCE OF EXCEEDING 100 DEGF AT KSFF MONDAY INCREASING TO
57% TUESDAY AND 42% WEDNESDAY
- 2% CHANCE OF EXCEEDING 100 DEGF AT KGEG MONDAY INCREASING TO 6%
TUESDAY AND 1% WEDNESDAY
- 92% CHANCE OF EXCEEDING 100 DEGF AT KLWS FRIDAY AND REMAINS OVER
60% THROUGH WEDNESDAY
- 34% CHANCE OF EXCEEDING 100 DEGF AT KEAT MONDAY INCREASING TO
50% TUESDAY AND 26% WEDNESDAY
COMPARED TO PREVIOUS FORECASTS, ALL OF THESE NUMBERS ARE SLIGHTLY
HIGHER SO THIS TELLS ME THAT THERE IS INCREASING CONFIDENCE OF A
LONG-LIVED SIGNIFICANT HEATWAVE THROUGH MIDWEEK.
HOW FAST THE RIDGE BREAKS DOWN LATE NEXT WEEK REMAINS THE BIG
QUESTION. NO INDICATIONS AT THIS TIME THAT A LARGE SWEEPING
CHANGE IS EXPECTED BUT IT IS IMPORTANT TO REMEMBER THAT SOME OF
OUR MOST EXTREME FIRE EVENTS HAVE OCCURRED LATE IN THE SEASON
AFTER A PROLONGED DRY SPELL, PARTICULARLY AFTER A HEATWAVE. HOW
VIGOROUSLY THIS RIDGE BREAKS DOWN WILL BE CRITICAL TO WATCH LATE
NEXT WEEK. /AB
AVIATION
06Z TAFS: HIGH PRESSURE IS STRENGTHENING OVER NORTHERN ROCKIES
WHICH WILL SWITCH THE WINDS AROUND AND INCREASE FROM THE
NORTHEAST DURING THE MORNING HOURS FRIDAY. TAF LOCATIONS KCDA-
KSFF-KGEG WILL SEE THE MOST NOTICEABLE INCREASE WITH POTENTIAL
GUSTS OVER 12 KTS DURING THE LATE MORNING AND EARLY AFTERNOON.
STRONGER WINDS ARE EXPECTED TO CHANNEL DOWN THE NORTH-SOUTH
VALLEYS SO LOCATIONS LIKE KSZT AND KOMK WILL EXPERIENCE HIGHER
GUSTS OUT OF THE NORTH. AFTER SUNSET, THE WINDS WILL SUBSIDE
BUT REMAIN OUT OF THE NORTH TO NORTHEAST ACROSS THE REGION.
WITH THE SWITCH IN WIND DIRECTION AND INCREASE IN FIRE ACTIVITY
IN WESTERN MONTANA, THERE IS ALSO THE POSSIBILITY OF SMOKE
DRIFTING OVER NORTHERN IDAHO AND SPREADING INTO EASTERN WA
DURING THE DAY FRIDAY. REDUCED VISIBILITY DUE TO HAZE WAS NOT
MENTIONED IN THE 06Z TAFS BUT IT IS SOMETHING WE'LL WATCH
CLOSELY OVERNIGHT AND FRIDAY MORNING.
FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: HIGH CONFIDENCE
IN INCREASING NE WIND FRIDAY MORNING. LOW CONFIDENCE THAT SMOKE
WILL REDUCE VISIBILITY IN NORTH IDAHO AND EASTERN WA.
/AB
-----------------------
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 90 58 94 61 95 61 / 0 0 0 0 0 0
COEUR D'ALENE 90 58 94 61 95 61 / 0 0 0 0 0 0
PULLMAN 91 54 94 58 95 58 / 0 0 0 0 0 0
LEWISTON 97 63 100 67 101 68 / 0 0 0 0 0 0
COLVILLE 89 48 93 50 95 53 / 0 0 0 0 0 0
SANDPOINT 86 53 91 55 93 55 / 0 0 0 0 0 0
KELLOGG 87 60 92 63 94 65 / 0 0 0 0 0 0
MOSES LAKE 94 60 98 63 99 64 / 0 0 0 0 0 0
WENATCHEE 93 68 97 72 99 73 / 0 0 0 0 0 0
OMAK 94 61 98 63 100 65 / 0 0 0 0 0 0
OTX WATCHES/WARNINGS/ADVISORIES
WA...EXTREME HEAT WATCH FROM SATURDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR CENTRAL CHELAN COUNTY-LOWER GARFIELD AND
ASOTIN COUNTIES-MOSES LAKE AREA-OKANOGAN VALLEY-UPPER
COLUMBIA BASIN-WATERVILLE PLATEAU-WENATCHEE AREA-WESTERN
OKANOGAN COUNTY.
ID...EXTREME HEAT WATCH FROM SATURDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR LEWISTON AREA.
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