502  
FXUS66 KPDT 200307  
AFDPDT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PENDLETON OR  
808 PM PDT SAT AUG 19 2017  
   
UPDATE
 
HIGH PRESSURE WILL BE OVER THE AREA THE NEXT SEVERAL DAYS.  
A WEAK WAVE WILL MOVE ACROSS THE AREA SUNDAY WITH SOME MOSTLY HIGH  
CLOUDS ACROSS THE NORTHERN FORECAST AREA. THESE CLOUDS WILL EXIT THE  
AREA IN TIME FOR THE ECLIPSE. AT 10 AM MONDAY TEMPERATURES IN  
CENTRAL OREGON SHOULD BE IN THE LOWER 70S WITH LIGHT WINDS UNDER  
CLEAR SKIES. FOR TONIGHT EXPECT JUST A FEW THIN CIRRUS AND  
DIMINISHING WINDS. LOWS WILL BE IN THE 50S WITH MOSTLY 40S IN THE  
MOUNTAINS. THE CURRENT FORECAST IS ON TRACK AND NO SIGNIFICANT  
CHANGES ARE NEEDED FOR THE TEXT OR GRIDDED FORECAST THIS EVENING.  
78  
 

 
   
AVIATION...06Z TAFS
 
VFR CONDITIONS WITH JUST A FEW HIGH CLOUDS  
WILL PERSIST THROUGH THE FORECAST PERIOD. SMOKE FROM LOCAL FIRES IN  
CENTRAL OREGON HAS RELAXED A BIT SO SIGNIFICANT IMPACTS ARE NOT  
EXPECTED AT KBDN AND KRDM. WINDS WILL BE LIGHT AND TERRAIN DRIVEN. 78  
 

 
   
PREV DISCUSSION
 
/ISSUED 400 PM PDT SAT AUG 19 2017/  
 
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT...A FLAT WESTERLY FLOW  
WILL CONTINUE THROUGH SUNDAY AND THEN A RIDGE WILL BEGIN TO AMPLIFY  
OVER THE REGION ON MONDAY. A SHORTWAVE PASSING TO THE NORTH WILL  
SPREAD SOME HIGH CLOUDS OVER THE AREA ON SUNDAY BUT THEN SKIES CLEAR  
SUNDAY NIGHT AND REMAIN CLEAR FOR THE SOLAR ECLIPSE MONDAY.  
TEMPERATURES WILL REMAIN NEARLY PERSISTENT SUNDAY BUT THEN WARM  
SLIGHTLY MONDAY DUE TO THE BUILDING RIDGE. OVERALL WINDS WILL REMAIN  
LIGHT WITH SOME LOCALLY BREEZY CONDITIONS ALONG THE EAST SLOPES OF  
THE CASCADES IN THE LATE AFTERNOON AND EVENINGS.  
 
LONG TERM...TUESDAY THROUGH THURSDAY NIGHT...MID/UPPER LEVEL RIDGE  
OF HIGH PRESSURE REMAINS OVER THE REGION TUESDAY FOR DRY CONDITIONS.  
HIGH TEMPS TUESDAY FOR LOWLANDS WILL BE IN THE MID TO UPPER 90S AND  
IN THE MID 70S TO UPPER 80S IN MOUNTAINS. TUESDAY NIGHT THE RIDGE  
AXIS MOVES INTO IDAHO THUS ALLOWING WINDS ALOFT TO BACK TO THE  
SOUTHWEST WHILE A LOW PRESSURE SYSTEM IN CALIFORNIA STARTS MOVING  
NORTHWARD TOWARD OREGON. ON WEDNESDAY A LONGWAVE TROUGH IN THE GULF  
OF ALASKA DIGS SOUTH AND CAPTURES THE LOW SOUTH OF THE CWA THEREBY  
TRANSPORTING MOISTURE AND SOME INSTABILITY INTO CENTRAL OREGON  
OVERNIGHT AND THEN INTO THE MOUNTAINS OF NE OREGON AFTER DAYBREAK ON  
WEDNESDAY. THIS SETS THE STAGE FOR A CHANCE OF SHOWERS AND A SLIGHT  
CHANCE OF AFTERNOON/EVENING THUNDERSTORMS WEDNESDAY IN CENTRAL AND  
NE OREGON WITH A CHANCE OF SHOWERS AND A SLIGHT CHANCE OF NOCTURNAL  
THUNDERSTORMS IN THE BLUE MOUNTAINS CONTINUING THROUGH OVERNIGHT AND  
DAYBREAK TO MIDDAY THURSDAY MORNING. THE AFOREMENTIONED LONGWAVE  
TROUGH IN THE NE PACIFIC PUSHES A COLD FRONT TOWARD THE COAST  
WEDNESDAY NIGHT AND THEN SWEEPS THE COLD FRONT THROUGH THE FORECAST  
AREA DURING THE DAY ON THURSDAY FOR COOLER HIGH TEMPERATURES IN THE  
UPPER 70S TO MID 80S AND UPPER 60S TO LOWER 80S MOUNTAINS. TIGHT  
PRESSURE GRADIENTS ASSOCIATED WITH THE COLD FRONT WILL PRODUCE  
BREEZY TO WINDY CONDITIONS ON THURSDAY WITH PATCHY BLOWING DUST IN  
THE LOWER COLUMBIA BASIN. THE COLD FRONT EXITS THE REGION THURSDAY  
EVENING WITH DECREASING WINDS OVERNIGHT AND DRY CONDITIONS. POLAN  
 
FRIDAY THROUGH SUNDAY MORNING...MODELS ARE IN REASONABLE AGREEMENT  
ON A TREND OF GRADUALLY INCREASING HEIGHTS AS AN AREA OF LOW  
PRESSURE CONTINUES TO MOVE EASTWARD ACROSS THE CANADIAN PRAIRIES.  
HIGH TEMPERATURES WILL REBOUND FROM THE UPPER 70S TO LOWER 80S ON  
FRIDAY TO THE UPPER 80S TO LOWER 90S BY SATURDAY. WINDS WILL BE  
LIGHT WITH NO SIGNIFICANT CLOUD COVER EXPECTED. 74  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
PDT 58 84 53 87 / 0 0 0 0  
ALW 61 85 58 90 / 0 0 0 0  
PSC 56 88 56 91 / 0 0 0 0  
YKM 58 87 56 91 / 0 0 0 0  
HRI 59 87 55 90 / 0 0 0 0  
ELN 59 84 54 89 / 0 0 0 0  
RDM 46 84 46 88 / 0 0 0 0  
LGD 51 82 47 86 / 0 0 0 0  
GCD 52 84 51 87 / 0 0 0 0  
DLS 63 86 62 90 / 0 0 0 0  
 

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

 
 

 
 
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