124  
FXUS66 KPDT 071541  
AFDPDT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PENDLETON OR  
841 AM PDT TUE JUL 7 2020  
   
UPDATE
 
MINOR EDITS THIS MORNING. TROUGH/COLD FRONT CONTINUE TO  
PUSH EAST OF THE REGION THIS MORNING, BRINGING AN END TO LINGERING  
SHOWERS/STORMS ACROSS WALLOWA COUNTY. IN ITS WAKE, DRY CONDITIONS,  
OUTSIDE OF SHOWERS ALONG CASCADE CREST, THEN EXPECTED AS THE FLOW  
BECOMES WESTERLY. BREEZY TO WINDY CONDITIONS AND COOLER TEMPS  
EXPECTED BEHIND THE FRONT WITH HIGHS UPPER 60S TO LOW 80S. WINDS  
WILL LIKELY REACH ADVISORY CRITERIA IN THE KITTITAS VALLEY AND  
THE GORGE EAST OF THE DALLES. WEAK TRANSIENT RIDGE PUSHES ACROSS  
THE REGION TONIGHT INTO WEDNESDAY. THIS WILL BRING AN END TO  
CASCADE SHOWERS AND ALSO BRING SLIGHTLY WARMER TEMPS, LIGHTER  
WINDS AND MOSTLY SUNNY SKIES FOR WEDNESDAY. THE DRY AND CALM  
CONDITIONS CONTINUE WEDNESDAY NIGHT INTO MOST OF THURSDAY. WARMER  
TEMPS EXPECTED THURSDAY (UPPER 70S TO UPPER 80S) AS THE FLOW TURNS  
SOUTHWEST AS ANOTHER SHORTWAVE TROUGH/FRONT APPROACHES THE  
REGION. MODELS IN BETTER AGREEMENT ON TIMING AND HAVE IT PUSHING  
ACROSS THURSDAY NIGHT. NOT A LOT OF MOISTURE WITH THIS SYSTEM AS  
THE FLOW REMAINS WEST TO SOUTHWEST, BUT MAY BE ENOUGH MOISTURE AND  
INSTABILITY FOR BE A CHANCE OR SHOWERS/STORMS OVER THE EASTERN  
MOUNTAINS WITH SHOWERS ALONG THE CASCADE CREST. MANY AREAS OF THE  
LOWER COLUMBIA BASIN AND SURROUNDING VALLEYS WILL EXPERIENCE  
BREEZY TO WINDY CONDITIONS ONCE AGAIN WITH GUSTS MAINLY AROUND  
25-35 MPH...LOCALLY HIGHER.  
 

 
   
AVIATION...18Z TAFS
 
VFR CONDITIONS WILL PREVAIL THROUGH THE  
PERIOD. OUTSIDE OF SOME THIN CIRRUS AND PERHAPS A FEW AFTERNOON  
CUMULUS CLOUDS SKIES WILL BE CLEAR. WINDS INCREASE TO  
14-22G22-30KTS. COULD BE GUSTS UP TO 35KTS AT DLS AND PDT. WINDS  
WILL DECREASE TONIGHT TO AROUND 10KTS OR LESS AND REMAIN LOWER  
THROUGH TOMORROW, EXCEPT AT DLS WHICH WILL INCREASE TO 12-18KTS.  
 

 
   
PREV DISCUSSION
 
/ISSUED 310 AM PDT TUE JUL 7 2020/  
 
SHORT TERM...TODAY THROUGH THURSDAY NIGHT. A SHORTWAVE TROUGH AND  
SURFACE COLD FRONT MAKING ITS WAY ACROSS THE FORECAST AREA HAVE  
BOTH SURFACE AND ELEVATED INSTABILITY FOR SCATTERED THUNDERSTORMS  
ACROSS A LARGE PORTION OF THE FORECAST AREA, EVEN FARTHER WEST  
THAN PREVIOUSLY ANTICIPATED. PRECIPITATION AMOUNTS HAVE BEEN LESS  
THAN 0.10 INCH ALONG WITH REPORTS OF NEW FIRE STARTS. THE TROUGH  
IS NOW ALONG THE IDAHO BORDER WITH THUNDERSTORMS TAPERING OFF  
BEHIND IT. BY MID-MORNING, ANY SHOWERS WILL BE ALONG THE CASCADES  
WHERE A FAIRLY MOIST NORTHWEST FLOW ALOFT IS PRESENT AS WELL AS  
THE WALLOWA MOUNTAINS. THE SURFACE COLD FRONT HAS LEFT BREEZY  
WINDS IN ITS WAKE, AND THESE WINDS WILL CONTINUE THROUGH THE DAY.  
ANOTHER SHORTWAVE TROUGH TRAVELING ALONG THE WA/BC BORDER WILL  
ENHANCE THE WINDS IN THE KITTITAS VALLEY WHERE SUSTAINED WINDS  
30-40 MPH ARE LIKELY THIS AFTERNOON AND EVENING. THE EASTERN  
COLUMBIA RIVER GORGE--MAINLY EAST OF THE DALLES--WILL EXPERIENCE  
SIMILAR WINDS. A WIND ADVISORY WILL BE ISSUED FOR THESE TWO ZONES  
FOR THIS MORNING'S FORECAST PACKAGE. TEMPERATURES TODAY WILL BE  
ABOUT 5-10 DEGREES COOLER THAN YESTERDAY, AND AFTERNOON RHS WILL  
BE IN THE 20S TO MID-30S. RED FLAG CONDITIONS ARE NOT EXPECTED,  
BUT THERE COULD BE PROBLEMS CONTROLLING SOME FIRES EXPOSED TO  
GUSTY WINDS.  
 
TONIGHT THROUGH WEDNESDAY NIGHT CAN BE SUMMARIZED AS A DRY  
WESTERLY FLOW ALOFT. SHOWERS ALONG THE CASCADES WILL END  
OVERNIGHT. WINDS WILL DECREASE OVERNIGHT, AND WEDNESDAY'S WINDS  
WILL NOT BE AS STRONG BUT REMAIN WINDY IN THE TYPICAL AREAS  
THROUGH THE CASCADE GAPS.  
 
THE NEXT SHORTWAVE TROUGH ARRIVES THURSDAY EVENING, BUT IT'S BEST  
DESCRIBED AS A MOSTLY DRY COLD FRONT. LIMITED MOISTURE AND  
INSTABILITY COULD BRING ISOLATED SHOWERS AND THUNDERSTORMS TO THE  
NORTHEAST MOUNTAINS, AND THE CASCADES WILL HAVE SCATTERED SHOWERS.  
MANY AREAS OF THE LOWER COLUMBIA BASIN AND SURROUNDING VALLEYS  
WILL EXPERIENCE BREEZY TO WINDY CONDITIONS ONCE AGAIN WITH GUSTS  
MAINLY AROUND 25-35 MPH...LOCALLY HIGHER. WISTER  
 
LONG TERM...FRIDAY THROUGH TUESDAY...MODELS IN GOOD AGREEMENT IN  
CONTINUING THE TROUGHY WEATHER PATTERN OVER THE PACIFIC NORTHWEST  
THROUGH THE PERIOD. GENERAL SOUTHWEST UPPER LEVEL FLOW WILL CONTINUE  
THROUGH SATURDAY AS A PERSISTENT TROUGH REMAINS OFF THE COAST  
OF BC. THE FLOW IS EXPECTED TO BECOME MORE ZONAL SUNDAY AND MONDAY  
AS THE AFOREMENTIONED TROUGH SLOWLY MOVES EAST. BY TUESDAY, THE  
UPPER LEVEL FLOW IS EXPECTED TO BECOME MORE NORTHWESTERLY AS A RIDGE  
TRIES TO BUILD OVER THE EASTERN PACIFIC. THERE IS ONE PROMINENT  
DIFFERENCE IN THIS SCENARIO TO KEEP AN EYE ON AS THE GFS SHOWS A  
WEAK LOW OFF THE COAST OF CALIFORNIA MOVING INLAND AND WEAKENING AS  
IT MOVES INTO SOUTHERN OREGON SATURDAY AFTERNOON. THIS COULD FIRE  
OFF SOME CONVECTION OVER OUR SOUTHERN CWA SATURDAY AFTERNOON AND  
EVENING IF IT PANS OUT; HOWEVER, THE ECMWF DOES NOT SHOW SUCH A  
FEATURE. AT THIS TIME WITH LIMITED MOISTURE, WILL KEEP THE WEATHER  
DRY OVER MUCH OF THE AREA, EXCEPT A FEW AFTERNOON AND EVENING  
SHOWERS OVER THE CASCADES, MAINLY THE WASHINGTON SIDE. DAYTIME  
HIGHS WILL REMAIN NEAR TO SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD.  
EARLE  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
PDT 76 52 81 54 / 0 0 0 0  
ALW 78 55 82 56 / 10 0 0 0  
PSC 81 56 85 57 / 0 0 0 0  
YKM 76 52 81 55 / 0 0 0 0  
HRI 79 55 84 56 / 0 0 0 0  
ELN 69 51 77 55 / 0 10 0 0  
RDM 72 44 80 47 / 0 0 0 0  
LGD 70 49 76 51 / 10 0 0 0  
GCD 72 48 79 51 / 10 0 0 0  
DLS 72 56 80 59 / 10 10 0 0  
 

 
   
PDT WATCHES/WARNINGS/ADVISORIES
 
 
OR...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 11 PM PDT THIS EVENING  
FOR ORZ041.  
 
WA...WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 11 PM PDT THIS EVENING  
FOR WAZ024-026.  
 

 
 

 
 
84/85/81/84  
 
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