Area Forecast Discussion
Issued by NWS Pendleton, OR

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FXUS66 KPDT 292242 AAA
AFDPDT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
342 PM PDT TUE JUL 29 2014

UPDATED AVIATION DISCUSSION

.SHORT TERM...TONIGHT THROUGH FRIDAY...RIDGE OF HIGH PRESSURE WILL
REMAIN OVER THE REGION THROUGH FRIDAY AND BEYOND. MOISTURE WORKING
ITS WAY AROUND THE HIGH WILL CONTINUE TO IMPACT THE FORECAST AREA
FROM CENTRAL OREGON TO NORTHEAST OREGON WITH SOME SHOWERS AND
ISOLATED THUNDERSTORMS MAINLY DURING THE AFTERNOON AND EVENING
HOURS. THE COVERAGE OF THE SHOWERS AND THUNDERSTORMS WILL GRADUALLY
INCREASE THROUGH THE WEEK AS MOISTURE BECOMES MORE ABUNDANT IN THE
ATMOSPHERE. THE HIGH WILL KEEP TEMPERATURES ABOVE NORMAL FOR BOTH
DAYTIME AND OVERNIGHT. OTHER THAN SOME LOCAL BREEZY WINDS ALONG THE
EAST SLOPES OF THE CASCADES WINDS WILL REMAIN LIGHT.

.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...A RIDGE OF HIGH PRESSURE
WILL CONTINUE TO REMAIN OVER THE WEST THROUGH AT LEAST MONDAY. OUR
AREA WILL BE ON THE WEST SIDE OF THE RIDGE IN A SOUTHWEST FLOW.
SEVERAL WAVES WILL MOVE THROUGH THE AREA AND RIDE OVER THE RIDGE AND
MODELS ARE COMING INTO SOMEWHAT BETTER AGREEMENT ABOUT THE DETAILS.
FRIDAY NIGHT THUNDERSTORMS WILL BE WINDING DOWN IN THE LATE EVENING
WITH A SLIGHT CHANCE OVER CENTRAL AND NORTH CENTRAL OREGON, THE
EASTERN OREGON MOUNTAINS AND THE WASHINGTON CASCADES NEAR CLE ELUM.
ON SATURDAY A WAVE WILL BE OFF THE COAST AND WILL CREATE A WEAK
TROUGH OFFSHORE. THIS WILL TURN THE FLOW MORE SOUTHERLY AND SEND A
STREAM OF MOISTURE INTO THE AREA. THERE WILL BE A SLIGHT CHANCE OF
THUNDERSTORMS OVER MOST OF THE AREA, THOUGH AT THIS POINT, THE
WASHINGTON COLUMBIA BASIN AND THE WASHINGTON CASCADES NORTH OF MOUNT
ADAMS LOOK DRY. ON SUNDAY THE WAVE WEAKENS IN THE ECMWF AND REMAINS
ALONG THE COAST IN THE GFS. THE ECMWF SHOWS LITTLE THUNDERSTORM
ACTIVITY WHILE THE GFS SHOWS ACTIVITY MAINLY OVER THE MOUNTAINS AND
CENTRAL OREGON. CURRENT FORECAST WAS SIMILAR TO THE GFS SO HAVE KEPT
IT FOR NOW. ON MONDAY THE ECMWF HAS THE RIDGE CENTERED OVER IDAHO
WITH ANOTHER DRY DAY WHILE THE GFS CONTINUES TO SHOW WEAKENING
CONVECTIVE ACTIVITY. HAVE CUT BACK A SLIGHT CHANCE OF THUNDERSTORMS
TO CENTRAL OREGON, THE EASTERN OREGON MOUNTAINS AND THE WASHINGTON
CASCADES. BY TUESDAY BOTH MODELS ARE HINTING THAT AN UPPER LOW IN
THE GULF OF ALASKA WILL NUDGE THE RIDGE OVER INTO MONTANA. THIS WILL
MAINTAIN THE SOUTHWEST FLOW AND WHILE MOISTURE IS MARGINAL,
INSTABILITY WILL STILL BE PRESENT SO HAVE KEPT A SLIGHT CHANCE OF
THUNDERSTORMS OVER THE EASTER OREGON MOUNTAINS. TEMPERATURES WILL
CONTINUE TO BE IN THE MID 90S AND LOWER 100S WITH MID 80S TO MID 90S
IN THE MOUNTAINS. PERRY

&&

.AVIATION...00Z TAFS...VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24
HOURS. THUNDERSTORMS WITH SCT-BKN CLOUDS ABOVE 10000 FEET AGL HAVE
DEVELOPED OVER CENTRAL OREGON AND THE OCHOCO-JOHN DAY HIGHLANDS THIS
AFTERNOON AND SHOULD CONTINUE THROUGH 04Z-05Z. THIS WILL AFFECT KBDN
AND KRDM AND HAVE PLACED VCTS IN THE TAFS FOR THOSE SITES. THE REST
OF THE AREA WILL HAVE FEW-SCT HIGH CUMULUS AND CIRRUS INITIALLY BUT
CLOUD COVER WILL INCREASE AS THUNDERSTORM BLOWOFF REACHES AREAS
FURTHER NORTH. COVERAGE WILL DECREASE OVERNIGHT. 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 THROUGH 05Z AND AGAIN AFTER 18Z. KRDM
AND KBDN MAY HAVE WINDS OF 10-20 KTS WITH HIGHER GUSTS DURING NEARBY
THUNDERSTORM ACTIVITY. PERRY

&&

.FIRE WX...WARM AND DRY CONDITIONS WILL PERSIST AS A RIDGE OF HIGH
PRESSURE REMAINS OVER THE REGION. OVERNIGHT HUMIDITY RECOVERY WILL
BE POOR TO MODERATE...ESPECIALLY ALONG THE RIDGES EAST OF THE
CASCADES. FURTHERMORE...MONSOON MOISTURE MOVING INTO THE AREA WILL
BRING ISOLATED THUNDERSTORMS TO CENTRAL OREGON...THE JOHN DAY
HIGHLANDS AND WALLOWA COUNTY THROUGH THIS EVENING. EACH DAY THIS
WEEK...SHOWER AND THUNDERSTORM CHANCES WILL INCREASE AND SPREAD
NORTH AND EAST AS SEVERAL WEAK DISTURBANCES INTERACT WITH THE
MONSOON FLOW. HOWEVER...THUNDERSTORMS SHOULD MOSTLY STAY SOUTH OF
THE WASHINGTON BORDER UNTIL FRIDAY. ANY STORMS THAT DEVELOP WILL
INITIALLY HAVE LIMITED PRECIPITATION SO WILL MONITOR STORM
DEVELOPMENT AS WELL AS MODEL CONSISTENCY TO DETERMINE IF ANY RED
FLAG WARNINGS WILL NEED TO BE ISSUED IN THE COMING DAYS.  COBB


&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  68  99  67  98 /  10  10  10  10
ALW  71  99  71  99 /   0  10  10  10
PSC  68 102  68 101 /   0   0   0  10
YKM  65 100  64 100 /   0   0   0  10
HRI  68 101  67 100 /   0   0   0  10
ELN  59  99  59  98 /   0   0   0  10
RDM  57  94  57  93 /  30  20  20  20
LGD  61  94  62  93 /  20  20  20  20
GCD  66  93  63  91 /  30  20  30  20
DLS  67  97  65  97 /   0  10  10  10

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...HEAT ADVISORY UNTIL 9 PM PDT WEDNESDAY WAZ028.

&&

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

$$

91/83/83






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