769  
FXUS66 KPDT 110539  
AFDPDT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PENDLETON OR  
1039 PM PDT SUN AUG 10 2025  
   
AVIATION...06Z TAFS
 
LOW AVIATION CONCERNS THE NEXT 24-HRS WITH  
VFR PREVAILING. LARGELY CLEAR SCENE ON SATELLITE OUTSIDE SOME  
HIGH CLOUDS WORKING SOUTH OWING TO A WEAK SUBTLE SHORTWAVE TROUGH  
MOVING INTO THE FAR NORTHERN INTERMOUNTAIN WEST. GENERAL LIGHT,  
DIURNAL WIND REGIME WITH WEAK CROSS-CASCADE GRADIENT WITH HIGHEST  
SPEEDS SEEN IN THE AFTERNOON, 5-10 KTS, AT TAF SITES. LARGELY  
CLEAR SKIES. SMALL WILDFIRE NEAR KRDM, CANAL FIRE, CONTINUES TO BE  
REPORTED AT ASOS THIS EVENING. HOWEVER, RESTRICTIONS IN  
VISIBILITY ARE NOT ANTICIPATED OWING TO FAVORABLE WIND DIRECTION  
WHICH SHOULD LIMIT SMOKE TRANSPORT TOWARDS THE TERMINAL BUT BEARS  
WATCHING NONETHELESS.  
 

 
 
PREV DISCUSSION... /ISSUED 108 PM PDT SUN AUG 10 2025/  
 
DISCUSSION...  
STRONG HIGH PRESSURE WILL BUILD OVER THE PACIFIC NORTHWEST TODAY  
AND REMAIN OVER THE AREA THROUGH MONDAY BEFORE GETTING PUSHED  
SOUTHWARD ON TUESDAY. BY LATER TUESDAY A MORE ZONAL WESTERLY FLOW  
WILL MOVE INTO THE REGION AND REMAIN FOR THE REST OF THE WEEK.  
 
THE RIDGE OF HIGH PRESSURE WILL BRING VERY HOT TEMPERATURES TO THE  
AREA, BEGINNING TODAY AND PEAKING MONDAY AND TUESDAY. EXTREME HEAT  
WARNINGS ARE IN EFFECT AND MOST LOWER ELEVATION LOCATIONS WILL BE  
IN MODERATE HEATRISK TODAY. MODERATE HEATRISK BECOMES MORE  
WIDESPREAD MONDAY AND TUESDAY WITH PORTIONS OF THE COLUMBIA  
BASIN, BLUE MOUNTAIN FOOTHILLS, YAKIMA AND KITTITAS VALLEYS,  
COLUMBIA GORGE AND AND CENTRAL OREGON REACHING MAJOR HEATRISK.  
 
HIGH TEMPERATURES COULD TOP OUT IN THE 102-103 RANGE IN THE  
HOTTEST LOCATIONS. THESE WOULD BE ABOUT 15 DEGREES ABOVE NORMAL.  
THE ECMWF EFI DOES KEY IN ON THE TEMPERATURES, WITH VALUES MAINLY  
IN THE 0.7 TO 0.8 RANGE, ESPECIALLY ACROSS THE BASIN.  
 
AFTER TUESDAY, WE WILL SEE A GRADUAL COOL DOWN, WITH WEDNESDAY  
BEING ABOUT 10 DEGREES COOLER THAN TUESDAY (BUT STILL ABOVE  
NORMAL) AND THURSDAY THROUGH THE REMAINDER OF THE PERIOD HAVING  
HIGH TEMPERATURES NEAR SEASONAL LEVELS, GENERALLY IN THE 80S.  
 
WINDS ARE EXPECTED TO INCREASE AS THE RIDGE BREAKS DOWN TUESDAY  
AND CONTINUE INTO WEDNESDAY. IT WILL BE BREEZY TO WINDY,  
ESPECIALLY LATER TUESDAY INTO WEDNESDAY, WITH BREEZY CONDITIONS  
CONTINUING INTO THURSDAY. LOW RH VALUES, ESPECIALLY ON TUESDAY AND  
WEDNESDAY WILL LEAD TO ENHANCED AND POSSIBLY CRITICAL FIRE  
WEATHER CONCERNS. THE LOWER TEMPERATURES THURSDAY ONWARD WILL HELP  
RAISE HUMIDITIES AND LOWER WINDS AFTER THURSDAY WILL ALSO HELP  
DECREASE CONCERNS BEYOND THEN. THE ECMWF EFI IS PICKING UP THE  
INCREASED WINDS ON WEDNESDAY, ESPECIALLY ACROSS THE COLUMBIA  
BASIN AND FOOTHILLS OF THE BLUE MOUNTAINS, WITH VALUES OF 0.7 TO  
0.8, MAINLY.  
 
NO PRECIPITATION IS EXPECTED UNTIL FRIDAY INTO SATURDAY, AND THEN  
ONLY OVER THE MOUNTAINS.  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
PDT 64 99 65 99 / 0 0 0 0  
ALW 70 99 71 100 / 0 0 0 0  
PSC 65 101 66 102 / 0 0 0 0  
YKM 66 99 69 101 / 0 0 0 0  
HRI 65 102 66 102 / 0 0 0 0  
ELN 65 97 66 97 / 0 0 0 0  
RDM 56 99 58 99 / 0 0 0 0  
LGD 60 97 62 98 / 0 0 0 0  
GCD 60 98 63 100 / 0 0 0 0  
DLS 71 103 72 100 / 0 0 0 0  
 

 
   
PDT WATCHES/WARNINGS/ADVISORIES
 
 
OR...EXTREME HEAT WARNING UNTIL 10 PM PDT TUESDAY FOR ORZ041-044-505-  
507-508-510-511.  
 
WA...EXTREME HEAT WARNING UNTIL 10 PM PDT TUESDAY FOR WAZ024-026>029-  
521.  
 

 
 

 
 
SHORT TERM...77  
LONG TERM....77  
AVIATION...80  
 
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