Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 032220 AAA
AFDPDT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
320 PM PDT TUE MAY 3 2016

UPDATED AVIATION DISCUSSION

.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT.  AFTER SEVERAL DAYS OF
WARM SUNNY WEATHER...EASTERN WA/OR WILL SEE MORE ACTIVITY THROUGH
FRIDAY.  THE ELONGATED HIGH PRESSURE RIDGE HAS SHIFTED
EASTWARD...LEAVING THE FORECAST AREA ON THE BACKSIDE OF THE RIDGE
AND UNDER A SOUTHERLY FLOW ALOFT.  MOISTURE AND INSTABILITY WILL
INCREASE OVER THE NEXT 72 HOURS...AND THE CHANCE OF SHOWERS AND
THUNDERSTORMS WILL INCREASE AS WELL.  CURRENTLY...SHOWERS HAVE
DEVELOPED ALONG THE CASCADES ALONG WITH A ROGUE THUNDERSTORM NEAR
SNOQUALMIE PASS.  BELIEVE ANY CONVECTIVE ACTIVITY WILL BE CONFINED
WEST OF GOLDENDALE...CONDON AND PAULINA.  CLOUDS WILL INCREASE OVER
THE REMAINDER OF THE FORECAST AREA WHICH WILL KEEP OVERNIGHT LOWS
SEVERAL DEGREES HIGHER THAN LAST NIGHT.

ON WEDNESDAY...SCATTERED TO NUMEROUS SHOWERS WILL DEVELOP EAST OF
THE CASCADES.  WITH SURFACE-BASED CAPES INCREASING TO 300-500 J/KG
AND LI`S LOWERING TO -3C TO -5C...THE THREAT OF THUNDERSTORMS WILL
BE GREATER.  HOWEVER...THE HORSEFLY IN THE OINTMENT IS THE
THICKENING CLOUD COVER THAT WILL LIKELY INHIBIT CONVECTION.
THEREFORE...WILL KEEP A SLIGHT CHANCE IN THE FORECAST FOR ALL ZONES
WEDNESDAY AFTN/EVE. AFTERNOON TEMPERATURES WILL ALSO BE ABOUT 5-10
DEGREES COOLER COMPARED TO TODAY.

A CLOSED LOW OVER CALIFORNIA ON THURSDAY WILL CIRCULATE ADDITIONAL
MOISTURE OVER EASTERN OR/WA.  THE STRONGEST THUNDERSTORMS FOR THIS
WEEK WILL LIKELY OCCUR ON THURSDAY...ESPECIALLY OVER FAR NE OREGON
WHERE BULK SHEAR MAGNITUDE IS 35-45 KNOTS AND CAPES WILL APPROACH
1200 J/KG (NOTE THE 12Z GFS IS NOT AS SIGNIFICANT AS PREVIOUS RUNS
WITH THE AMOUNT OF FORCING).  CURRENT FORECAST OF CHANCE OF
THUNDERSTORMS IN OUR EASTERN ZONES AND SLIGHT CHANCE ELSEWHERE
APPEARS ON TRACK.  PRECIPITATION WILL TAPER OFF FROM THE NORTHWEST
THURSDAY NIGHT WHEN THE LOW TRACKS INTO SOUTHERN CALIFORNIA.  WISTER

.LONG TERM...FRIDAY THROUGH TUESDAY...A LARGE CLOSED LOW WILL
DRIFT NORTHEAST FROM CALIFORNIA ACROSS THE GREAT BASIN INTO THE
CENTRAL ROCKIES FRIDAY THROUGH SUNDAY. FRIDAY AFTERNOON AND EVENING
A FEW WRAPAROUND SHOWERS OR THUNDERSTORMS MAY OCCUR FROM GRANT TO
WALLOWA COUNTIES AND THE NORTHERN BLUE MOUNTAINS. FRIDAY NIGHT AND
SATURDAY AN UPPER LEVEL RIDGE WILL BUILD OVER WASHINGTON.
HOWEVER...EASTERLY FLOW AROUND THE LOW IN CALIFORNIA/ARIZONA MAY
KEEP SHOWERS ALONG THE SOUTHEASTERN EDGE OF THE CWA WHILE DRIER
CONDITIONS SPREAD INTO EASTERN WASHINGTON. SUNDAY THROUGH TUESDAY
WILL BE DRY AS NORTHWESTERLY FLOW DEVELOPS OVER THE AREA. IT WILL BE
WINDY AT TIMES. FRIDAY EVENING GUSTY N-NELY WINDS WILL DEVELOP
BETWEEN THE BUILDING RIDGE IN WASHINGTON AND THE LOW TO THE
SOUTHEAST. SUNDAY AFTERNOON AND EVENING A MARINE PUSH THROUGH WILL
THE CASCADE GAPS WILL BRING STRONG WESTERLY WINDS ACROSS THE
COLUMBIA BASIN AND ADJACENT VALLEYS. TEMPERATURES WILL BE WARMING
FRIDAY THROUGH SUNDAY WITH HIGHS REACHING THE UPPER 80S IN THE
COLUMBIA BASIN THEN COOLING MONDAY AND TUESDAY BEHIND THE MARINE
PUSH INTO THE 70S.  COONFIELD

&&

.AVIATION...0Z TAFS...VFR CONDITIONS WILL PREVAIL FOR THE NEXT 24
HRS. MVFR CONDITIONS POSSIBLE NEAR THUNDERSTORM AFTER 20Z TOMORROW.
THERE ARE SOME CUMULUS BUILDUPS NEAR KRDM...KBDN... KDLS...AND KYKM
WITH SCT SHRA AND POSSIBLE TSRA. INCREASING MID AND HIGH CLOUDS
TONIGHT..ESPECIALLY WEST. DEBRIS CLOUDS PERSISTING OVERNIGHT KRDM
KBDN KDLS KYKM. WINDS WILL BE 5-15KT. 76

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  52  78  51  72 /  10  20  60  50
ALW  54  80  54  73 /  10  20  50  50
PSC  58  82  57  78 /  10  20  50  50
YKM  54  80  53  78 /  30  30  50  30
HRI  55  80  53  76 /  10  20  50  50
ELN  51  78  49  73 /  30  30  50  40
RDM  44  71  41  68 /  50  70  70  50
LGD  46  79  48  68 /  10  30  50  50
GCD  48  77  47  68 /  10  50  60  70
DLS  54  75  51  75 /  40  40  50  40

&&

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

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

$$

85/76/76

!--NOT SENT--!



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