Area Forecast Discussion
Issued by NWS Pendleton, OR

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000
FXUS66 KPDT 251002
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
300 AM PDT MON MAY 25 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT...AN UPPER LOW OVER
SOUTHERN BRITISH COLUMBIA WILL GRADUALLY DRIFT SOUTHEAST THROUGH
THIS PERIOD. THIS LOW WILL REACH NORTHEAST OREGON TUESDAY NIGHT. THE
UPPER LOW`S POSITION OVER EASTERN WASHINGTON THIS AFTERNOON WILL
KEEP THE ONSHORE FLOW GOING OVER MUCH OF SOUTHEAST WASHINGTON AND
NORTHEAST AND CENTRAL OREGON THROUGH THIS EVENING. THIS FLOW IS
RELATIVELY STABLE, THUS SHOWERS AND THUNDERSTORMS WILL AGAIN BE
LIMITED TODAY AND THIS EVENING. AT THIS TIME EXPECT ISOLATED TO
SCATTERED SHOWERS WITH ISOLATED THUNDERSTORMS OVER SOUTH CENTRAL
WASHINGTON AND THE EASTERN MOUNTAIN ZONES (MAINLY THE BLUES EAST TO
WALLOWA COUNTY). A FEW SHOWERS SHOULD PERSIST ACROSS OUR NORTHERN
ZONES OVERNIGHT TONIGHT INTO TUESDAY MORNING. WITH THE UPPER LOW
MOVING TOWARDS AND INTO NORTHEAST OREGON TUESDAY AFTERNOON AND
TUESDAY NIGHT, EXPECT THE AIR MASS OVER SOUTHEAST WASHINGTON AND
NORTHEAST OREGON TO BECOME MORE UNSTABLE. WILL THEREFORE CONTINUE TO
INDICATE SLIGHT CHANCE TO CHANCE SHOWERS AND SLIGHT CHANCE
THUNDERSTORMS IN THESE AREAS TUESDAY AFTERNOON AND EVENING. SOME
SHOWERS SHOULD LINGER OVER THE NORTHERN MOST ZONES LATE TUESDAY
NIGHT. HIGH AND LOW TEMPS WILL CONTINUE TO RUN NEAR TO SLIGHTLY
ABOVE SEASONAL THROUGH THIS PERIOD. 90

.LONG TERM...WEDNESDAY THROUGH SUNDAY...A MID/UPPER LEVEL LOW WILL
BE OVER SOUTHEAST WASHINGTON AND NORTHEAST OREGON WEDNESDAY MORNING
MOVING EAST INTO IDAHO BY WEDNESDAY AFTERNOON, THUS KEEPING WRAP
AROUND MOISTURE AND A MARGINALLY UNSTABLE ATMOSPHERE OVER THE
EASTERN MOUNTAINS DURING THE DAY ON WEDNESDAY WITH A SLIGHT CHANCE
OF AFTERNOON AND EVENING THUNDERSTORMS OVER THE BLUE MOUNTAINS AND
THE WALLOWA MOUNTAINS. WEDNESDAY NIGHT THE LOW OPENS UP TO A TROUGH
OVER IDAHO, WHICH KEEPS NORTHERLY UPSLOPE FLOW AGAINST THE MOUNTAINS
OF NORTHEAST OREGON AND SOUTHEAST WASHINGTON FOR A SLIGHT CHANCE OF
SHOWERS THROUGH THE NIGHT, MAINLY IN THE BLUE MOUNTAINS AND THE
WALLOWA MOUNTAINS. THURSDAY A WEAK RIDGE BUILDS OVER THE REGION, BUT
WILL KEEP A SLIGHT CHANCE OF A SHOWER IN THE EASTERN MOUNTAINS AND
ALONG THE EAST SLOPES OF THE CENTRAL WASHINGTON CASCADES FOR
THURSDAY. THURSDAY NIGHT THE RIDGE IS SQUARELY OVER THE REGION WITH
ASSOCIATED SINKING AIR PROVIDING DRY CONDITIONS. FRIDAY THE RIDGE
MOVES EAST INTO IDAHO THUS SETTING THE STAGE FOR SOUTHWEST FLOW
ALOFT TO BEGIN TRANSPORTING PACIFIC MOISTURE INTO THE REGION. THIS
MOISTURE FLUX INTO THE FORECAST AREA INCREASES THROUGH THE WEEKEND
FOR A CHANCE OF SHOWERS IN THE HIGHER TERRAIN OF CENTRAL AND
NORTHEAST OREGON ON SATURDAY AND SUNDAY AS WELL AS IN THE BLUE
MOUNTAINS OF SOUTHEAST WASHINGTON. DAYTIME SURFACE HEATING WILL
YIELD MARGINALLY INSTABILITY FOR A SLIGHT CHANCE OF AFTERNOON AND
EARLY EVENING THUNDERSTORMS OVER THE MOUNTAINS THROUGH THE WEEKEND.
POLAN

&&

.AVIATION...12Z TAFS...VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24
HOURS. WINDS ARE EXPECTED TO REMAIN BELOW 15 KTS EXCEPT AT KDLS
WHERE THEY WILL BECOME BREEZY 15 TO 25 KTS IN THE AFTERNOON.  POLAN

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  76  48  77  51 /  10  10  20  20
ALW  77  54  78  56 /  10  10  30  30
PSC  81  53  81  55 /  10  10  20  20
YKM  81  51  80  52 /  10  20  30  30
HRI  80  50  81  53 /  10  10  10  20
ELN  76  53  78  53 /  10  20  40  40
RDM  75  38  76  40 /  10  10   0  10
LGD  71  46  72  48 /  20  20  30  20
GCD  75  44  76  45 /  20  10  10  10
DLS  75  54  77  56 /  10  10  10  20

&&

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

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

$$

90/99/99


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