Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 022325 AAA
AFDPDT

AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE PENDLETON OR
425 PM PDT SUN AUG 2 2015

UPDATED AVIATION DISCUSSION

.SHORT TERM...TONIGHT THROUGH WEDNESDAY. A STRONG HIGH PRESSURE
SYSTEM CONTINUES TO PRODUCE VERY HOT CONDITIONS AS AFTN TEMPS AGAIN
SOAR ABOVE THE CENTURY MARK ACROSS PORTIONS OF THE BASIN AND THE
SURROUNDING AREA. HOWEVER THE HIGH PRESSURE WAS SLIPPING TO THE EAST
AND IS ALLOWING A RETURN FLOW OF MOISTURE INTO OUR WESTERN ZONES
WHERE THE ADDITIONAL CLOUD COVER WAS KEEPING TEMPS FROM RISING AS
FAST TODAY. SHOWERS/TSRA WILL WORK THERE WAY INTO THE WA/OR CASCADES
OVERNIGHT AND THEN SPREAD EASTWARD AFFECTING THE ENTIRE AREA MONDAY
AFTERNOON AS A DISTURBANCE WORKS ITS WAY ACROSS THE REGION. AFTN
HIGH TEMPS WILL BE NOTICEABLE LOWER BY AS MUCH AS FIVE TO TEN
DEGREES BECAUSE OF THE CLOUDS AND SHOWERS INTO MONDAY EVENING. DRIER
AIR IS FORECAST TO WORK ITS WAY INTO OUR WESTERN ZONES MONDAY NIGHT
AND THE BULK OF THE PCPN WILL SHIFT INTO THE BLUE/WALLOWA MOUNTAINS
MONDAY NIGHT AND TUESDAY. MOISTURE WILL ALSO LINGER OVER CENTRAL
OREGON AND A FEW SHOWERS/TSRA ARE POSSIBLE HERE AS WELL TUESDAY
AFTN. AS THE DISTURBANCE MOVES WELL EAST OF THE REGION OUR AREA
SHOULD RETURN TO MOSTLY DRY CONDITIONS AND NEAR SEASONABLE TEMPS BY
MIDWEEK.

&&

.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY NIGHT...THE EXTENDED
PERIOD STARTS OFF MAINLY DRY AS A NORTHWEST FLOW AND WEAK TRANSIENT
UPPER RIDGE DEVELOP OVER THE AREA WEDNESDAY NIGHT THROUGH THE FIRST
HALF OF FRIDAY. WESTERLY WINDS COULD REMAIN A LITTLE BREEZY
WEDNESDAY EVENING AS THE PRESSURE GRADIENT IS SLOW TO RELAX. FRIDAY
NIGHT THROUGH SATURDAY AFTERNOON AN UPPER LEVEL TROUGH PASSES BY
JUST TO THE SOUTH OF THE FORECAST AREA. THIS UPPER LEVEL FEATURE
WILL COMBINE WITH INCREASING MOISTURE AND INSTABILITY TO LEAD TO A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS...ESPECIALLY OVER THE
MOUNTAINS OF CENTRAL AND NORTHEAST OREGON. HEADING INTO SUNDAY AND
SUNDAY NIGHT MOST GUIDANCE IS NOW IN AGREEMENT THAT A BROAD UPPER
TROUGH WITH AN ASSOCIATED UPPER LEVEL LOW WILL BEGIN TO APPROACH THE
REGION FROM OFF THE WASHINGTON COAST. THE EXACT TRACK OF THIS
FEATURE WILL HAVE LARGE IMPLICATIONS ON JUST HOW MUCH MOISTURE MAY
MOVE INTO OUR CWA. THE CURRENT GUIDANCE IS INDICATING PLENTY OF MID
LEVEL MOISTURE...INSTABILITY ALONG WITH A CYCLONIC FLOW AND
INCREASED VERTICAL MOTION OVER THE CWA. THIS WOULD ALLOW SHOWERS AND
THUNDERSTORMS TO DEVELOP OVER MUCH OF THE REGION. WOULD LIKE TO SEE
MORE RUN TO RUN CONSISTENCY IN THIS SOLUTION BEFORE RAISING POPS TOO
MUCH HIGHER...CONSIDERING IT IS DAY 7 DECIDED TO GO WITH A SLIGHT
CHANCE TO LOW END CHANCE OF SHOWERS AND THUNDERSTORMS FOR
NOW...STILL PLENTY OF TIME TO WATCH THIS SYSTEM. WITH THE ADDED
CLOUD COVER AND MOISTURE AROUND TEMPERATURES WILL CONTINUE TO BE
HELD IN CHECK MUCH CLOSER TO AVERAGE LEVELS. THIS EQUATES TO HIGHS
IN THE MID 80S TO LOWER 90S FOR THE LOWER ELEVATIONS THROUGH THE
ENTIRE EXTENDED PERIOD WITH 70S TO LOWER 80S IN THE MOUNTAINS. 77

&&

.AVIATION....00Z TAFS...VFR CONDITIONS WILL CONTINUE AT ALL TAF
SITES OVER THE NEXT 24 HOURS. A SERIES OF DISTURBANCES MOVING UP
FROM THE SOUTH WILL INCREASE MID AND HIGH CLOUDS OVER THE AREA
TONIGHT AND ESPECIALLY INTO MONDAY. CLOUD BASES WILL START BETWEEN
15-25KFT AGL TONIGHT BEFORE LOWERING TO BETWEEN 07-15KFT AGL AFTER
03/15Z. A FEW SHOWERS WILL BE POSSIBLE AT OR INVOF KBDN AND KRDM
MAINLY FROM 03/08Z THROUGH 03/15-18Z. NORTHWEST WINDS WILL BE BREEZY
AT KDLS...KBDN AND KRDM INTO THE EVENING HOURS...WITH GUSTS BETWEEN
15-25KTS POSSIBLE HERE. LOOK FOR WINDS AOB 12KTS AT ALL OTHER TAF
SITES THROUGH MONDAY MORNING. AFTER 03/18Z WESTERLY WINDS WILL AGAIN
INCREASE TO BETWEEN 15-25KTS AT KDLS...KPDT...KALW AND KPSC. 77

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  69  90  61  92 /  10  20  10  10
ALW  73  92  66  93 /  10  20  10  10
PSC  65  96  65  96 /  10  20  10  10
YKM  69  92  61  89 /  10  10  10   0
HRI  67  94  63  94 /  10  20  10  10
ELN  67  92  61  90 /  10  10  10   0
RDM  59  87  50  87 /  30  30  20  20
LGD  55  85  53  88 /  10  20  30  20
GCD  60  91  54  90 /  10  30  30  20
DLS  70  93  64  91 /  20  30  10   0

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 9 PM PDT THIS EVENING FOR ORZ639-641.

     FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY EVENING
     FOR ORZ639-641.

     HEAT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR ORZ041-044-507.

WA...RED FLAG WARNING UNTIL 9 PM PDT THIS EVENING FOR WAZ639-641-643.

     FIRE WEATHER WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY EVENING
     FOR WAZ639-641-675.

     HEAT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR WAZ024-027>029.

&&

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

$$

97/77/77


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