Area Forecast Discussion
Issued by NWS Pendleton, OR

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000
FXUS66 KPDT 300943
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
244 AM PDT WED JUL 30 2014

.SHORT TERM...TODAY THROUGH FRIDAY. SHORT WAVE MOVING ACROSS THE
AREA SET OFF SCATTERED THUNDERSTORMS OVER CENTRAL OREGON YESTERDAY
AFTERNOON AND EVENING. THIS ACTIVITY DIMINISHED OVERNIGHT HOWEVER
SATELLITE SHOWS SOME REMAINING CLOUDINESS STILL MOVING THROUGH THE
REGION. BASED ON MOVEMENT SPEED MOST OF THE CLOUDS SHOULD MOVE OFF
TO THE NORTHEAST LATER THIS MORNING. EXPECT A PERIOD OF SUNNY SKIES
THEN INCREASING CLOUDS AGAIN AS INSTABILITY AND ANOTHER SHORT WAVE
BRING ADDITIONAL SHOWERS AND THUNDERSTORMS TO CENTRAL AND NORTHEAST
OREGON THIS AFTERNOON AND EVENING. CLOUD COVER HAS KEPT TEMPERATURES
FAIRLY WARM AND SHOULD HAVE ANOTHER DAY WITH HIGHS IN THE 90S WITH
100-105 IN THE COLUMBIA BASIN. NOT MUCH CHANGE TO THE OVERALL
PATTERN THE NEXT FEW DAYS AS HIGH PRESSURE REMAINS ANCHORED OVER THE
WESTERN PORTION OF THE COUNTRY WITH A SOUTH SOUTHWEST FLOW ALOFT
INTO THE AREA. MONSOON MOISTURE AND OCCASIONAL SHORT WAVES WILL
COMBINE WITH DAYTIME INSTABILITY TO GENERATE SHOWERS AND
THUNDERSTORMS EACH DAY. FOR THURSDAY APPEARS THE ACTIVITY WILL AGAIN
BE MOSTLY OVER CENTRAL AND NORTHEAST OREGON. MODELS SHOWING ACTIVITY
ON FRIDAY MAY EXPAND NORTHWARD INTO WASHINGTON. CURRENT FORECAST HAS
THIS COVERED. TEMPERATURES WILL REMAIN HOT HOWEVER INCREASED
CLOUDINESS DURING THE DAY MAY CUT DOWN ON HIGHS A FEW DEGREES
THURSDAY AND ESPECIALLY FRIDAY. 94

.LONG TERM...FRIDAY NIGHT THROUGH MONDAY...EASTERN OREGON AND
WASHINGTON WILL BE ON THE WESTERN SIDE OF AN UPPER LEVEL RIDGE
THROUGH AT LEAST MONDAY MORNING. SEVERAL WAVES WILL MOVE THROUGH THE
AREA AND RIDE OVER THE RIDGE. SUBSIDENCE FROM THE RIDGE WILL BRING
SOUTH TO SOUTHWEST FLOW AND HOT TEMPERATURES TO THE REGION. THIS
SOUTHERLY FLOW WILL ALSO BRING MONSOON MOISTURE INTO THE AREA AT
TIMES. THUNDERSTORMS ACTIVITY WILL BE ENHANCED BY HEATING DURING THE
AFTERNOON AND EVENING...BUT WEAK WAVES MAY TRIGGER NIGHTTIME
CONVECTION AS WELL.

SOUTHWEST FLOW WILL BE OVER THE AREA FRIDAY. THE GFS AND ECMWF BRING
A WAVE THROUGH THE AREA FRIDAY AFTERNOON. EXPECT CONVECTION TO
LINGER INTO THE EVENING BEFORE DECREASING OVERNIGHT. SATURDAY
ANOTHER WAVE WILL FORM OFFSHORE AND MOVE INTO EASTERN OREGON AND
WASHINGTON SATURDAY NIGHT AND SUNDAY. THIS WILL REINFORCE THE
SOUTHERLY FLOW AND KEEP A CHANCE OF THUNDERSTORMS OVER THE CWA.
MONDAY THE GFS KEEPS A SOUTHERLY FLOW AND BRINGS ANOTHER WEAK WAVE
TO ENHANCE THUNDERSTORM ACTIVITY. THE ECMWF DEVELOPS A WESTERLY FLOW
WITH THE BEST CONVECTIVE POTENTIAL IN SOUTHERN IDAHO AND MONTANA.
THE GFS ENSEMBLES SHOW BOTH SCENARIOS. KEPT A PERSISTENCE FORECAST
WITH SLIGHT CHANCE OF THUNDERSTORMS CENTRAL TO NORTHEAST OREGON
MOUNTAINS...BUT HAVE LOW CONFIDENCE IN DETAILS. TUESDAY BOTH 0Z
MODELS INDICATE DRY WESTERLY FLOW DEVELOPING BUT ENOUGH INSTABILITY
AND MOISTURE MAY LINGER OVER THE NORTHEAST OREGON MOUNTAINS TO
TRIGGER THUNDERSTORMS AGAIN TUESDAY AFTERNOON/EVENING.  COONFIELD

&&

.AVIATION...06Z TAFS...VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24
HOURS. SCT-BKN MID AND HIGH LEVEL CLOUDS FROM BLOWOFF OF PREVIOUS
THUNDERSTORMS POSSIBLE TONIGHT AT ALL TAF SITES.  EXPECT THAT
COVERAGE WILL DECREASE AS THE NIGHT MOVES ON. TOMORROW AFTERNOON
EXPECT A REPEAT OF THUNDERSTORMS IN CENTRAL OREGON AFTER 21Z AND
HAVE VCTS IN THE TAFS ONCE AGAIN AT KBDN AND KRDM. SURFACE WINDS
WILL GENERALLY REMAIN BELOW 15 KTS FOR THE NEXT 24 HOURS THOUGH KDLS
MAY HAVE SOME GUSTS TO 20 KTS OVER THE NEXT COUPLE OF HOURS AND GUST
UP TO 30 KTS AFTER 18Z WHEN THE WINDS PICK UP AGAIN. KRDM AND KBDN
MAY HAVE WINDS OF 10-20 KTS WITH HIGHER GUSTS DURING NEARBY
THUNDERSTORM ACTIVITY. WEBER

&&

.FIRE WEATHER...FIRE WEATHER WATCHES REMAIN IN EFFECT FOR THE
CENTRAL AND NORTHEAST OREGON ZONES THROUGH SATURDAY FOR
THUNDERSTORMS WITH ABUNDANT LIGHTNING.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT 104  68  98  69 /  10  10  10  10
ALW 104  71  99  73 /   0  10  10  10
PSC 104  68 101  70 /   0   0  10  10
YKM 103  66  99  69 /   0   0  10  10
HRI 104  68 100  69 /   0   0  10  10
ELN 101  61  97  62 /   0   0  10  10
RDM  98  60  93  60 /  20  20  30  30
LGD  97  63  92  62 /  30  20  30  30
GCD  96  63  92  63 /  30  30  30  30
DLS  98  66  97  68 /  10  10  10  10

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FIRE WEATHER WATCH FROM 1 PM PDT THIS AFTERNOON THROUGH SATURDAY
     EVENING ORZ049-050-502-503-505>507-509>511.

     HEAT ADVISORY FROM NOON TODAY TO 9 PM PDT THIS EVENING
     ORZ044-507.

WA...FIRE WEATHER WATCH FROM 1 PM PDT THIS AFTERNOON THROUGH SATURDAY
     EVENING WAZ030.

     HEAT ADVISORY FROM NOON TODAY TO 9 PM PDT THIS EVENING
     WAZ027-029.

     HEAT ADVISORY UNTIL 9 PM PDT THIS EVENING WAZ028.

&&

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

$$

94/76/76





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