Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 311506
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
806 AM PDT MON AUG 31 2015

.SHORT TERM...TODAY AND TONIGHT...NO CHANGE TO THE FORECAST. BROAD
TROUGH WILL CONTINUE OVER THE PACIFIC NORTHWEST WITH A WESTERLY FLOW
BRINGING SOME PRECIPITATION TO THE WASHINGTON CASCADES BUT OTHERWISE
DRY FOR THE REST OF THE FORECAST AREA. TEMPERATURES WILL BE A LITTLE
WARMER TODAY WITH WESTERLY WINDS 5 TO 15 MPH.


&&

.PREV DISCUSSION... /ISSUED 258 AM PDT MON AUG 31 2015/

SHORT TERM...MONDAY THROUGH WEDNESDAY...MODELS ARE IN GOOD
AGREEMENT IN HAVING A BROAD UPPER LEVEL TROUGH OVER THE PACIFIC
NORTHWEST AND WESTERN CANADA. A WESTERLY FLOW WILL BE CROSSING THE
AREA THROUGH TUESDAY MORNING AND PRECIPITATION WILL BE LIMITED TO
SOME LIGHT SHOWERS ALONG THE WASHINGTON CASCADES, PERHAPS MAKING IT
DOWN TO ELLENSBURG AT TIMES. BY TUESDAY AFTERNOON AN UPPER LOW WILL
BE DROPPING SOUTH ALONG THE BRITISH COLUMBIA COAST AND DEEPENING THE
TROUGH SOUTHWARD. THIS WILL TURN THE FLOW MORE SOUTHWESTERLY AND
BRING THE LIGHT SHOWERS INTO THE OREGON CASCADES AS WELL ON TUESDAY
AFTERNOON. TUESDAY NIGHT THE LOW WILL SEND A WAVE ASHORE AND A
SLIGHT CHANCE OF SHOWERS WILL EXPAND INTO THE EASTERN MOUNTAINS AND
WALLOWA COUNTY OVERNIGHT WHILE THE REST OF THE AREA ASIDE FROM IN
AND NEAR THE CASCADES WILL REMAIN DRY. ON WEDNESDAY THE WAVE WILL
BRING A CHANCE OF RAIN SHOWERS TO THE MOUNTAINS AND A SLIGHT CHANCE
TO THE LOWER ELEVATIONS THOUGH THE COLUMBIA BASIN WILL REMAIN DRY.
RAIN AMOUNTS WILL GENERALLY BE LESS THAN A TENTH OF AN INCH.
TEMPERATURES WILL BE IN THE 70S AND LOWER 80S TODAY AND TUESDAY BUT
WITH THE TROUGH MOVING ASHORE, TEMPERATURES WILL BE IN THE MID 60S
TO MID 70S ON WEDNESDAY. PERRY

LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...AN UPPER LEVEL TROUGH
WILL BE EXITING THE AREA WEDNESDAY EVENING WITH LINGERING CHANCES
FOR SHOWERS MAINLY OVER THE EASTERN MOUNTAINS. THURSDAY WILL BE IN
BETWEEN STORMS SYSTEMS SO MOSTLY DRY CONDITIONS ARE EXPECTED WITH
COOL TEMPERATURES. ON FRIDAY AN UPPER LEVEL TROUGH WILL BE OVER THE
AREA WITH A GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS ESPECIALLY
DURING THE AFTERNOON AND EVENING. AFTER FRIDAY THE MEDIUM RANGE
MODELS DIVERGE. THE ECMWF CLOSES A LOW OFF OVER THE REGION WHILE THE
GFS IS MUCH MORE PROGRESSIVE. IF THE ECMWF IS CORRECT THERE COULD BE
SIGNIFICANT RAINS ON SATURDAY AND SATURDAY NIGHT ESPECIALLY OVER
EASTERN OREGON. THE GFS SOLUTION WOULD BE DRY. FOR NOW HAVE KEPT LOW
CHANCES FOR SHOWERS AND THUNDERSTORMS OVER THE EASTERN MOUNTAINS FOR
SATURDAY AND SATURDAY NIGHT UNTIL IT BECOMES A BIT MORE CLEAR ON
WHAT WILL TRANSPIRE ON THE WEEKEND. BY MONDAY IT SHOULD BE DRYING
OUT WITH WESTERLY FLOW. TEMPERATURES WILL BE COOL FOR MUCH OF THE
PERIOD WITH SOME FREEZING TEMPERATURES AT NIGHT POSSIBLE IN THE
MOUNTAINS AND SNOW LEVELS 6-7 THOUSAND FEET. IT WILL WARM UP A BIT
TOWARD THE END OF THE WEEKEND INTO EARLY NEXT WEEK WITH TEMPERATURES
CLOSER TO NORMAL FOR THIS TIME OF YEAR. 78

AVIATION...12Z TAFS...VFR CONDITIONS WILL PREVAIL THROUGH THE
FORECAST PERIOD. THERE WILL BE EXTENSIVE HIGH CLOUDS AT AROUND 20000
FEET AGL. THERE COULD BE A FEW STRATOCUMULUS AT 6-8K FEET BUT NOT
EXPECTING THESE CLOUDS TO PRODUCE A CEILING. WINDS WILL BE MAINLY
WESTERLY AT 7-12 KT AFTER 18Z BECOMING LIGHT TERRAIN DRIVEN AFTER
06Z. 78

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  78  52  79  55 /   0   0  10  10
ALW  79  59  80  60 /   0   0  10  10
PSC  81  58  83  57 /  10   0  10  10
YKM  75  51  75  51 /  10  10  10  20
HRI  80  55  81  56 /   0   0  10  10
ELN  75  53  77  50 /  10  10  20  20
RDM  78  42  78  46 /   0   0   0  20
LGD  78  48  82  48 /  10   0   0  10
GCD  82  46  85  48 /   0   0   0  10
DLS  79  59  80  60 /  10   0  10  20

&&

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

FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON

$$

91/79/79



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