673  
FXUS66 KPDT 211715  
AFDPDT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PENDLETON OR  
1015 AM PDT SAT SEP 21 2019  
 
UPDATED AVIATION DISCUSSION.  
   
UPDATE
 
AREAS OF FOG/LOW STRATUS SHOWING UP ON THE SATELLITE  
THIS MORNING ACROSS PORTIONS OF CENTRAL/NORTHEAST OREGON. ADDED  
FOG UNTIL 11AM FOR THESE AREAS. OTHERWISE, ONLY MINOR EDITS TO THE  
GRIDS. RIDGING TODAY WITH JUST A FEW HIGH CLOUDS AND WARMER TEMPS  
EXPECTED. A COLD FRONT SWEEPS ACROSS THE REGION TOMORROW AND  
TOMORROW NIGHT, BRINGING A GOOD CHANCE OF RAIN SHOWERS,  
ESPECIALLY OVER THE MOUNTAINS. AN VERY OUTSIDE CHANCE OF A STORM  
OR TWO OVER CENTRAL OR LATE AFTERNOON/EARLY EVENING, BUT  
INSTABILITY IS VERY MARGINAL, SO HAVE KEPT THUNDER OUT OF  
FORECAST. NORTHWEST FLOW FOLLOW THE DEPARTING SYSTEM FOR EARLY  
NEXT WEEK. DRIER CONDITIONS EXPECTED, BUT EXPECT VARIABLE  
CLOUDINESS AND A SLIGHT CHANCE FOR SHOWERS OVER THE MOUNTAINS,  
ESPECIALLY THE WA CASCADES, AS PACIFIC MOISTURE IN THE NW FLOW  
TRIES TO CLIP THE REGION. A DRY COLD FRONT ON TUESDAY COULD BRING  
BREEZY TO WINDY CONDITIONS AS IT MIXES DOWN STRONGER WINDS ALOFT.  
ADVISORY LEVEL WINDS POSSIBLE AS WINDS ALOFT ARE RUNNING +2 TO +3  
STANDARD DEVIATIONS. WARM TODAY WITH HIGHS IN THE UPPER 60S TO  
UPPER 70S. SLIGHTLY COOLER TOMORROW AND EARLY NEXT WEEK WITH HIGHS  
IN THE LOWER 60S TO MID 70S.  
 
AVIATION...18Z TAFS...VFR CONDITIONS CONTINUE WITH LIGHT WINDS  
EXPECTED FOR THE NEXT 24 HOURS. A FEW CLOUDS ABOVE 25,000 FT ACROSS  
THE EASTERN PORTION OF THE REGION WILL GRADUALLY DIMINISH THROUGH  
THE AFTERNOON. AS A COLD FRONT ARRIVES FROM THE WEST TOMORROW  
MORNING EXPECTED SHOWERS AND LIGHT RAIN TO GRADUALLY MOVE INTO THE  
REGION. BECAUSE OF THIS HAVE ADDED VCSH TO KYKM, KDLS, KRDM & KBDN  
AFTER 15Z SUNDAY MORNING. RICHARDS  
 

 
   
PREV DISCUSSION
 
/ISSUED 205 AM PDT SAT SEP 21 2019/  
 
SHORT TERM...TODAY THROUGH MONDAY...AN UPPER RIDGE WITH WARMER AND  
DRY CONDITIONS WILL MOVE ACROSS THE REGION AND FORECAST AREA TODAY.  
WINDS WILL BE LIGHT AND TEMPERATURES WILL BE PLEASANT IN THE MID TO  
UPPER 70S IN THE LOWER ELEVATIONS AND MOSTLY 60S IN THE MOUNTAINS.  
THEN A CHANGE IS IN STORE FOR TONIGHT AND SUNDAY AS ANOTHER UPPER  
TROUGH DROPS DOWN FROM THE NORTHWEST INTO THE REGION. THIS WILL  
BRING A PERIOD OF RAIN BY MORNING AND THROUGH THE MORNING ON SUNDAY,  
FOLLOWED BY INSTABILITY SHOWERS SUNDAY AFTERNOON AND EVENING AS THE  
UPPER TROUGH AXIS PASSES OVER THE FORECAST AREA WITH COLDER AIR  
ALOFT. THIS INSTABILITY WILL BE TOO MARGINAL TO MENTION ANY  
THUNDERSTORMS, BUT WOULD NOT RULE A STRAY LIGHTNING STRIKE SOMEWHERE  
IN THE FORECAST AREA SUNDAY AFTERNOON OR EARLY EVENING. TEMPERATURES  
ON SUNDAY WILL ONLY BE A DEGREE OR TWO COOLER THAN TODAY DUE TO  
MAINLY THE SOUTHWEST FLOW AHEAD OF THE TROUGH AXIS. ON MONDAY A  
TRANSITORY RIDGE WILL MOVE ACROSS THE REGION WITH MOSTLY DRY  
CONDITIONS. IT WILL BE A SEVERAL DEGREES COOLER BEHIND SUNDAY'S  
UPPER TROUGH. THERE WILL BE SOME SLIGHT INCREASE IN WIND WITH THE  
PASSING TROUGH ON SUNDAY, AND THEN AGAIN ON MONDAY AFTERNOON DUE TO  
MIXING, BUT WINDS WILL BE MOSTLY LIGHT THROUGH THE SHORT TERM  
FORECAST PERIOD. DESPITE THE FEW DEGREES DIFFERENCES IN TEMPERATURES  
FROM DAY TO DAY, TEMPERATURES WILL BE NOT BE TOO FAR FROM NORMAL FOR  
LATE MID-LATE SEPTEMBER ON ANY OF THE DAYS IN THE SHORT TERM. 88  
 
LONG TERM...MONDAY NIGHT THROUGH SATURDAY...A DRY NORTHWEST FLOW  
WILL BE OVER THE REGION MONDAY NIGHT THROUGH WEDNESDAY. IT WILL BE  
WARM ON TUESDAY WITH HIGHS IN THE 70S AND 60S IN THE MOUNTAINS. A  
DRY COLD FRONT WILL CROSS THE AREA TUESDAY WITH GUSTY WEST WINDS. BY  
WEDNESDAY NIGHT A FEW SHOWERS WILL BE POSSIBLE AS AN UPPER LOW  
STARTS TO DEVELOP OVER THE NORTHWEST. THE LOW WILL SETTLE OVER  
OREGON BY FRIDAY WITH COLD TEMPERATURES, CONTINUED SHOWERS AND SOME  
SNOW SHOWERS ABOVE 5000 FEET ESPECIALLY AT NIGHT. SNOW LEVELS LOWER  
EVEN FURTHER ON SATURDAY WITH THE UPPER LOW LINGERING. SNOW SHOWERS  
WILL BE POSSIBLE DOWN TO 3500-4000 FEET SATURDAY MORNING BEFORE SNOW  
LEVELS RISE AND TEMPERATURES WARM DURING THE AFTERNOON. FRIDAY AND  
SATURDAY'S HIGH TEMPERATURES COULD BE 10 TO 15 DEGREES BELOW NORMAL  
FOR THIS TIME OF YEAR. 78  
 

 
   
PRELIMINARY POINT TEMPS/POPS
 
 
PDT 74 48 72 48 / 0 0 40 40  
ALW 76 52 77 52 / 0 0 40 50  
PSC 78 54 75 53 / 0 0 40 20  
YKM 76 49 69 45 / 0 0 60 20  
HRI 79 51 76 50 / 0 0 40 30  
ELN 74 49 67 46 / 0 0 60 30  
RDM 73 46 67 40 / 0 0 60 40  
LGD 71 47 71 48 / 0 0 40 60  
GCD 73 46 73 46 / 0 0 40 60  
DLS 78 55 70 52 / 0 0 60 30  
 

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

 
 

 
 
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