380  
FXUS66 KPDT 290959  
AFDPDT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PENDLETON OR  
300 AM PDT MON MAY 29 2017  
   
SHORT TERM
 
TODAY THROUGH WEDNESDAY. HIGH PRESSURE WILL DOMINATE  
THE AREAS WEATHER WITH MAINLY DRY CONDITIONS AND ABOVE NORMAL  
TEMPS TODAY. AFTERNOON TEMPS ARE EXPECTED TO CLIMB INTO THE 90S  
ACROSS SOME LOCATIONS IN THE BASIN. AS THE HIGH PRESSURE SLIPS  
EAST...A RETURN FLOW OF MOISTURE WILL WORK ITS WAY ALONG THE OR/WA  
CASCADES TONIGHT WHERE A FEW SHOWERS AND AN ISOLD TSRA IS  
POSSIBLE. A LOW PRESSURE SYSTEMS PUSHES TOWARD OUR AREA AND THE  
SHOWERS AND TSRA WILL SPREAD INTO CENTRAL OREGON AND THE JOHN DAY  
HIGHLANDS TUESDAY AFTERNOON. ALSO A COLD FRONT IS FORECAST TO MOVE  
THROUGH THE REGION AND THE TSRA SHOULD THEN EXPAND INTO THE  
BLUE/WALLOWA MOUNTAINS TUESDAY NIGHT. WITH THE PASSAGE OF THE  
FRONT...BREEZY WEST WINDS COULD DEVELOP IN THE GORGE AND SPREAD  
INTO PARTS OF THE COLUMBIA BASIN AND KITTITAS VALLEY.  
 
BY WEDNESDAY DRIER CONDITIONS CAN BE EXPECTED ACROSS OUR WESTERN  
ZONES AND NOTICEABLY COOLER TEMPS IS FORECAST. FURTHER EAST...  
SHOWERS ARE EXPECTED TO LINGER ESPECIALLY IN AND NEAR THE  
BLUE/WALLOWA MOUNTAINS.  
 
   
LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
 
A BROAD MID/UPPER  
LEVEL TROUGH IN THE GULF OF ALASKA SETS THE STAGE FOR A CYCLONIC  
FLOW ALOFT OVER THE FORECAST AREA WEDNESDAY NIGHT, WHICH WILL ALLOW A  
SW FLOW TO CONTINUE OVER THE EASTERN OREGON MOUNTAINS FOR A CHANCE  
OF SHOWERS WEDNESDAY NIGHT ALONG WITH A SLIGHT CHANCE OF EVENING  
THUNDERSTORMS IN THE BLUE MOUNTAINS WITH THREAT OF THUNDERSTORMS  
ENDING BY SUNSET. THURSDAY A MID/UPPER LEVEL SHORTWAVE IN THE  
UPSTREAM WESTERLY FLOW MAKES LANDFALL AND SWEEPS ACROSS INTERIOR  
PACIFIC NORTHWEST DURING THE DAY ON THURSDAY, THUS KEEPING A CHANCE  
OF OROGRAPHIC SHOWERS OVER THE EASTERN OREGON MOUNTAINS WITH A  
SLIGHT CHANCE OF THUNDERSTORMS IN THE BLUE MOUNTAINS DURING THE  
AFTERNOON/EVENING. THURSDAY NIGHT THE SHORTWAVE EXITS INTO IDAHO IN  
THE EVENING RESULTING IN SHOWERS TAPERING OFF AND ENDING IN THE  
EVENING. FRIDAY THROUGH THE WEEKEND FLAT HIGH PRESSURE WILL KEEP  
DRY CONDITIONS IN THE REGION. POLAN  
 

 
   
AVIATION...12Z TAFS
 
CLEAR SKIES TONIGHT INTO MONDAY MORNING. SCT  
CUMULUS 060-090 DEVELOPING IN THE AFTERNOON MAINLY OVER THE  
MOUNTAINS. WINDS 5-10KT. POLAN  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
PDT 89 56 92 54 / 0 0 10 30  
ALW 91 61 92 59 / 0 0 10 20  
PSC 95 55 97 59 / 0 0 10 30  
YKM 94 59 93 57 / 0 10 10 30  
HRI 93 54 94 57 / 0 0 10 30  
ELN 93 55 87 56 / 0 10 20 40  
RDM 89 49 83 42 / 0 20 30 20  
LGD 84 47 91 56 / 0 0 10 20  
GCD 89 52 92 53 / 0 10 20 20  
DLS 95 60 78 56 / 0 10 20 30  
 

 
   
PDT WATCHES/WARNINGS/ADVISORIES
 
 
OR...NONE.  
WA...NONE.  

 
 

 
 
97/99/99  
 
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