277  
FXUS66 KPDT 182103  
AFDPDT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PENDLETON OR  
203 PM PDT FRI JUL 18 2025  
   
DISCUSSION...TONIGHT THROUGH FRIDAY. KEY MESSAGES  
 
- CRITICAL FIRE WEATHER CONDITIONS THIS AFTERNOON AND EVENING  
WITH HOT, DRY, AND WINDY CONDITIONS, EXCEPT ACROSS NORTHEAST OR  
AND THE UPPER EAST SLOPES OF THE WA CASCADES  
- HEIGHTENED FIRE WEATHER CONDITIONS SATURDAY ACROSS THE LOWER  
BASIN AND KITTITAS VALLEY  
- SLIGHT CHANCE OF ISOLATED THUNDERSTORMS OVER THE WA CASCADES  
AND EASTERN MOUNTAINS MONDAY  
- COOLER, NEAR AVERAGE SUNDAY INTO EARLY NEXT WEEK WITH HIGHS  
REBOUNDING ABOVE AVERAGE WEDNESDAY ONWARD WITH A DRYING TREND  
LATE NEXT WEEK.  
 
LATEST WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH DESCENDING  
INTO WA WITH A LOW OVER BRITISH COLUMBIA IN TANDEM WITH  
INCREASING MID-LEVEL FLOW SPREADING INTO SOUTH CENTRAL WA. LATEST  
DAY CLOUD PHASE IMAGERY SHOWS LARGELY CLEAR SKIES OUTSIDE SOUTH  
CENTRAL WA DOWNSTREAM OF APPROACHING HIGH CLOUDS. THE SHORTWAVE  
TROUGH WILL CONTINUE DROPPING SOUTHEASTWARD WITH ITS ATTENDANT  
DRY COLD FRONT CROSSING THE AREA EARLY TONIGHT. INCREASING W-SW  
WINDS AHEAD OF THE FRONT WILL BE REINFORCED WITH THE STRONGEST  
WINDS AND GUSTS EXPECTED 5-11 PM TODAY WITH MINIMUM RH 10-20%  
COMMON ACROSS THE LOWER ELEVATIONS. INCREASED CONFIDENCE, 80% OR  
HIGHER, WITH GUSTS GREATER THAN 25 MPH ACROSS THE LOWER BASIN,  
EASTERN COLUMBIA GORGE, SOUTH CENTRAL WA; HIGHEST GUSTS SPILLING  
OUT OF THE EASTERN GORGE INTO NORTH CENTRAL OR AND THE KITTITAS  
VALLEY WHEREIN DAILY PEAK GUSTS OF 39 MPH OR MORE ARE ANTICIPATED  
(80-100% CHANCE). WINDS WILL THEN SUBSIDE AND LESSEN GRADUALLY  
OVERNIGHT.  
 
DESPITE COOLER AIR MASS POST-FRONTAL, A FAVORABLE OVERLAP OF  
BREEZY WINDS AND AFTERNOON HUMIDITY IS EXPECTED AGAIN AS THE  
UPPER LOW SAGS TO THE SOUTHERN BC-ALBERTA BORDER. OF WHICH,  
ELEVATED TO LOCALLY CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED  
ACROSS A PORTION OF THE EASTERN GORGE INTO NORTHERN SHERMAN,  
GILLIAM, MORROW COUNTIES AND KITTITAS VALLEY. HIGHS WILL DROP 4-8  
DEGREES TOMORROW FROM TODAY. MEANTIME, AFTERNOON RHS WILL BE NEAR  
TO SLIGHTLY ABOVE SEEN TODAY ACROSS SOUTH CENTRAL WA OWING TO  
MODEST ISENTROPIC DESCENT AND DRYING VIA 305-310 THETA SURFACES AS  
SEEN AMONG DETERMINISTIC GUIDANCE. BREEZY TO GUSTY WINDS STILL  
EXPECTED WITH MODEST PRESSURE DIFFERENCES SEEN CROSS-CASCADES  
THOUGH FLOW ALOFT NOT AS STRONG AS THIS AFTERNOON AND EVENING.  
 
QUIESCENT FIRE WEATHER CONDITIONS SUNDAY-TUESDAY WITH RESPECT TO  
HUMIDITY AND WINDS OWING TO A RELAXED PRESSURE GRADIENT AND MORE  
BL MOISTURE. WITH THE UPSTREAM AMPLIFICATION OF AN UPPER RIDGE IN  
THE EASTERN NORTH PACIFIC AND GULF OF ALASKA LATE SATURDAY-SUNDAY,  
MEAN MID-LEVEL TROUGHING WILL TAKE HOLD DOWNSTREAM OVER THE  
REGION SUNDAY-TUESDAY. THIS WITH INCREASED MOISTURE AND MARGINAL  
INSTABILITY WITH GUDIENCE SUPPORTING ROBUST PRECIPITABLE WATERS IN  
PLACE FOR THIS TIME OF YEAR WILL PROMOTE LOW CHANCES, 10-25%, FOR  
THUNDERSTORMS MONDAY ACROSS THE EASTERN MOUNTAINS AND WA  
CASCADES, INCLUDING CHANCES FOR WETTING RAIN AS HIGH AS 30%. THIS  
THREAT WILL THEN SHIFT FARTHER EAST TUESDAY, AND BE CONFINED TO  
THE FAR EASTERN MOUNTAINS.  
 
LOOKING ONWARD, ENSEMBLE GUIDANCE FAVORS A BUILDING UPPER-LEVEL  
RIDGE WEDNESDAY-THURSDAY OVER THE EASTERN CONUS WITH WEAK  
TROUGHING/ZONAL WESTERLY FLOW OVER THE REGION. MEANTIME,  
CLUSTERING SCENARIOS LEAN TOWARDS A WARMING AND DRYING TREND BY  
FRIDAY IN RESPONSE TO THE MOST LIKELY OUTCOME OF A SOUTHWEST FLOW  
REGIME TAKING HOLD BY FRIDAY (~75%). AS SUCH, DRYING AND WARMING  
TREND IS ANTICIPATED WITH HIGHS READING FEW-SEVERAL DEGREES ABOVE  
AVERAGE WEDNESDAY-FRIDAY. THIS SCENARIO COULD RESULT IN ELEVATED  
FIRE WEATHER CONCERNS. OF WHICH, LATEST HOT-DRY-WINDY REFLECTS  
THIS WITH GEFS SHOWING INCREASING CHANCE OF EXCEEDING THE 75TH AND  
90TH PERCENTILE WEDNESDAY AND THURSDAY ACROSS THE LOWER COLUMBIA  
BASIN AND SOUTH CENTRAL WA.  
 
 
   
PREV DISCUSSION  
/ISSUED 1116 AM PDT FRI JUL 18 2025/  
 
AVIATION...18Z TAFS...LOW AVIATION CONCERNS WITH WINDS THE MAIN  
AVIATION IMPACT THE NEXT 12 HOURS. BREEZY-GUSTY WINDS THIS  
AFTERNOON AND EVENING AHEAD OF A DRY COLD FRONT THAT WILL ADVANCE  
ACROSS THE AREA THIS EVENING/EARLY TONIGHT. HIGH CONFIDENCE IN  
FREQUENT GUSTS > 20 KTS AT ALL SITES; HIGHEST GUSTS AT KDLS WHERE  
30 KTS OR MORE EXPECTED WITH POTENTIAL (30-50%) FOR 30 KTS AT KPDT  
WITH LOWER CONFIDENCE. WINDS WILL BE ELEVATED OVERNIGHT WITH  
BREEZY WINDS CONTINUING. INCREASING MID- AND HIGH-LEVEL CLOUDS,  
HIGH-END VFR 7KFT OR HIGHER, AFTERNOON-EVENING WITH LOW SKY COVER  
RESUMING TOMORROW.  
 
 
   
PRELIMINARY POINT TEMPS/POPS  
 
PDT 95 61 88 59 / 0 0 0 0  
ALW 95 65 88 62 / 0 0 0 0  
PSC 98 60 91 58 / 0 0 0 0  
YKM 95 59 88 57 / 0 0 0 0  
HRI 97 61 90 60 / 0 0 0 0  
ELN 91 57 84 57 / 0 0 0 0  
RDM 91 52 85 49 / 0 0 0 0  
LGD 93 57 85 56 / 0 0 0 0  
GCD 93 56 87 53 / 0 0 0 0  
DLS 91 61 84 61 / 0 0 0 0  
 
 
   
PDT WATCHES/WARNINGS/ADVISORIES  
 
OR...RED FLAG WARNING UNTIL 10 PM PDT THIS EVENING FOR  
ORZ691-696-697-698-700-701-703.  
 
WA...RED FLAG WARNING UNTIL 10 PM PDT THIS EVENING FOR WAZ691.  
 
RED FLAG WARNING UNTIL 10 PM PDT THIS EVENING FOR WAZ690.  
 
 
 
 
 
SHORT TERM...80  
LONG TERM....80  
AVIATION...80  
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