Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 011143 AAA
AFDPDT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
443 AM PDT FRI AUG 1 2014

UPDATED AVIATION DISCUSSION

.SHORT TERM...TODAY THROUGH SUNDAY...ISOLATED TO SCATTERED
THUNDERSTORMS CONTINUE TO DEVELOP OVER THE NORTH OREGON CASCADE EAST
SLOPES THIS MORNING. SO FAR THERE HAS BEEN ONLY LIGHTNING AND LIGHT
RAIN WITH THESE STORMS BUT WILL MONITOR THEM. WILL HAVE TO INCREASE
POPS FOR THIS MORNING IN THIS AREA DUE TO THE ONGOING PRECIPITATION.
SOME INSTABILITY REMAINS THERE THROUGH THE EARLY MORNING HOURS
TODAY. MID LEVEL MONSOONAL MOISTURE AND INSTABILITY CONTINUES TO BE
PULLED NORTHWARD ON THE WEST SIDE OF AN UPPER RIDGE OVER THE INLAND
WEST. THIS WILL KEEP THE SLIGHT CHANCE TO CHANCE OF THUNDERSTORMS
OVER THE CWA THROUGH SATURDAY...WITH LINGERING STORMS OVER THE
CENTRAL OREGON AND EASTERN MOUNTAINS ON SUNDAY. AT THIS TIME
SATURDAY LOOKS TO BE THE MOST ACTIVE DAY FOR CONVECTION...FOLLOWED
BY TODAY. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED IN ALL AREAS TODAY AND SATURDAY WITH THE BEST CHANCES FROM
CENTRAL OREGON NORTHEAST TO THE BLUE MOUNTAINS EASTWARD. SOME STORMS
COULD BECOME STRONG WITH POSSIBLY EVEN A SEVERE STORM...BUT THERE IS
NOT A LOT OF CONFIDENCE THAT THERE WILL BE A SEVERE STORM.
TEMPERATURES WILL REMAIN NOT AS HOT DUE TO THE INCREASED CLOUD COVER
FROM THUNDERSTORMS. TEMPERATURES WILL BE IN THE MID 90S TO NEAR 100
EACH DAY TODAY THROUGH SUNDAY IN THE LOWER ELEVATIONS...WITH 80S IN
THE MOUNTAINS. WINDS WILL BE GENERALLY LIGHT EXCEPT POSSIBLY GUSTY
TO 40 MPH NEAR ANY THUNDERSTORMS. THERE WILL BE AN INCREASE IN
WESTERLY WINDS THROUGH THE COLUMBIA RIVER GORGE AND WESTERN LOWER
COLUMBIA BASIN ON SUNDAY IN RESPONSE TO AN INCREASED PRESSURE
GRADIENT. 88

.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...OUR AREA WILL BE ON THE
WESTERN EDGE OF A RIDGE CENTERED OVER THE ROCKIES SUNDAY EVENING
WITH A SOUTHWEST FLOW OVER THE AREA. THIS WILL FEED MOISTURE INTO
CENTRAL OREGON AND THE EASTERN OREGON MOUNTAINS AND GIVE THAT AREA A
SLIGHT CHANCE OF THUNDERSTORMS AND SHOWERS IN THE EVENING. IT WILL
DECREASE TO JUST A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
OVERNIGHT IN THE EASTERN MOUNTAINS. ON MONDAY A FEW WEAK
DISTURBANCES WILL AFFECT THE AREA THOUGH MODELS HAVE DIFFERENCES IN
HANDLING THEM. THESE DISTURBANCES ALONG WITH A MODEST SHIFT IN AN
UPPER LOW IN THE GULF OF ALASKA WILL SHOVE THE RIDGE EASTWARD INTO
THE MIDWEST. MODELS MAINTAIN A WEST TO SOUTHWEST FLOW DUE TO THE
DISTURBANCES ON MONDAY SO EXPECT THAT THERE WILL BE ANOTHER SLIGHT
CHANCE OF THUNDERSTORMS IN CENTRAL OREGON AND THE EASTERN MOUNTAINS
MONDAY AFTERNOON AND EVENING. BY TUESDAY THE GFS DEVELOPS A WESTERLY
FLOW OVER THE AREA AND DOES NOT SHOW ANY POTENTIAL FOR
THUNDERSTORMS. THE ECMWF IS MORE WESTERLY AS WELL, BUT HAS ENOUGH
MOISTURE AND INSTABILITY FOR A SLIGHT CHANCE OF THUNDERSTORMS IN THE
EASTERN OREGON MOUNTAINS. CURRENT FORECAST LEANS TOWARDS THE ECMWF
SO HAVE KEPT THAT UNTIL BETTER MODEL AGREEMENT IS REACHED. WEDNESDAY
THROUGH THURSDAY NIGHT BOTH MODELS DEVELOP A WEST TO NORTHWEST FLOW
OVER THE AREA AND IT LOOKS LIKE A DRY PERIOD IN BOTH MODELS SO HAVE
A DRY FORECAST FOR THAT PERIOD. ON FRIDAY THE GFS MAINTAINS THE
WESTERLY FLOW WHILE THE ECMWF BRINGS A WAVE ASHORE FRIDAY AFTERNOON.
THE GFS WOULD KEEP US DRY AGAIN WHILE THE ECMWF WOULD BRING A SLIGHT
CHANCE OF THUNDERSTORMS TO THE EASTERN MOUNTAINS OF OREGON. HAVE
KEPT THE FORECAST DRY FOR NOW. TEMPERATURES WILL BE IN THE MID 90S
TO LOWER 100S WITH 80S AND LOWER 90S IN THE MOUNTAINS, THOUGH
TEMPERATURES WILL BE IN THE LOWER END OF THOSE RANGES THURSDAY AND
FRIDAY. PERRY

&&

.AVIATION...12Z TAFS...VFR CONDITIONS ARE EXPECTED TO BE PREVALENT
OVER THE NEXT 24 HOURS. SKIES WILL BE SCATTERED TO BROKEN ABOVE
15000 FEET AGL THIS MORNING AND EARLY AFTERNOON. AFTER 20Z
THUNDERSTORMS WILL BEGIN DEVELOPING IN CENTRAL OREGON AND THE
EASTERN OREGON MOUNTAINS AFFECTING KRDM AND KBDN AND WILL SPREAD TO
THE REST OF THE AREA AND OTHER TAF SITES BY 23Z. THUNDERSTORMS WILL
DECREASE AFTER 05Z BUT WILL NOT END OVER THE EASTERN MOUNTAINS UNTIL
10Z OR SO. THUNDERSTORM CHANCES ARE GREATEST AT KRDM AND KBDN SO
HAVE USED -TSRA THERE. CHANCES ARE LOWER AT OTHER TAF SITES SO HAVE
USED VCTS FOR THEM. BRIEF MVFR VISIBILITIES WILL BE POSSIBLE NEAR
THE STRONGEST THUNDERSTORMS BUTS CIGS SHOULD REMAIN ABOVE 5000 FEET
AGL. WINDS WILL GENERALLY REMAIN BELOW 15 KTS THOUGH KDLS WILL REACH
10 TO 20 KTS WITH GUSTS TO 25 KTS FROM 20Z TO 05Z. WINDS WILL GUST
TO 35 KTS NEAR THUNDERSTORMS. PERRY

&&

.FIRE WX...(PREVIOUS DISCUSSION) WARM AND DRY CONDITIONS CONTINUE
UNDER A RIDGE OF HIGH PRESSURE WITH OVERNIGHT HUMIDITY RECOVERY POOR
TO MODERATE. THUNDERSTORM CHANCES WILL INCREASE AND SPREAD NORTH AND
EAST EACH DAY THROUGH SATURDAY. MOST STORMS SHOULD STAY SOUTH OF THE
WASHINGTON BORDER UNTIL FRIDAY AND SATURDAY. STORMS THAT DEVELOP
WILL BE A MIXTURE OF WET AND DRY WITH PRECIPITATION RANGING FROM A
FEW HUNDREDTHS OF AN INCH TO AROUND A QUARTER OF AN INCH. RED FLAG
WARNINGS ARE IN EFFECT FOR ABUNDANT LIGHTNING ACROSS CENTRAL
OREGON...NORTH CENTRAL OREGON AND THE NORTHEAST MOUNTAINS THROUGH
SATURDAY. DMH

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  96  66  95  65 /  20  20  20  20
ALW  98  70  98  70 /  20  20  20  20
PSC 100  65  99  66 /  20  20  20  20
YKM  97  65  96  66 /  20  20  20  20
HRI  99  65  98  64 /  20  20  20  20
ELN  94  61  93  62 /  20  20  20  20
RDM  92  56  89  51 /  30  30  30  30
LGD  91  59  90  59 /  30  30  30  30
GCD  92  59  91  58 /  30  30  30  30
DLS  95  66  92  65 /  20  20  20  20

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...RED FLAG WARNING UNTIL 11 PM PDT SATURDAY
     ORZ041-049-050-502-503-505>507-509>511.

WA...RED FLAG WARNING UNTIL 11 PM PDT SATURDAY WAZ030.

     FIRE WEATHER WATCH FROM 5 AM PDT EARLY THIS MORNING THROUGH
     THIS EVENING WAZ026-027-520.

&&

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

$$

88/83/83/84






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