Area Forecast Discussion
Issued by NWS Pendleton, OR

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000
FXUS66 KPDT 020510
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1010 PM PDT SUN MAY 1 2016

UPDATED AVIATION DISCUSSION

.SHORT TERM...TONIGHT AND MONDAY...HIGH PRESSURE WILL CONTINUE OVER
THE REGION WITH THIS AFTERNOONS CUMULUS CLOUDS OVER THE MOUNTAINS
BEGINNING TO DIMINISH. INCREASING SOUTHERLY FLOW WILL BRING SOME
MOISTURE INTO CENTRAL OREGON LATE MONDAY FOR A CHANCE OF
THUNDERSTORMS AND SHOWERS. TEMPERATURES WILL INCREASE SLIGHTLY ON
MONDAY FOR ANOTHER ABOVE NORMAL TEMPERATURE DAY. JUST MINOR CHANGES
MADE IN THE EVENING FORECAST UPDATE.

.AVIATION...06Z TAFS...VFR CONDITIONS WITH MOSTLY CLEAR SKIES WILL
PREVAIL FOR THE NEXT 24 HOURS AT ALL TAF SITES. THERE WILL BE SOME
CUMULUS BUILD UPS MONDAY AFTERNOON MAINLY IMPACTING KRDM AND KBDN
WITH A SLIGHT CHANCE OF THUNDERSTORMS NEAR THE CASCADE MOUNTAINS.
WINDS WILL GENERALLY BE LESS THAN 10 KTS.

&&

.PREV DISCUSSION... /ISSUED 213 PM PDT SUN MAY 1 2016/

SHORT TERM...TONIGHT THROUGH WEDNESDAY. WEAK INSTABILITY OVER THE
REGION DUE TO AN UPPER LOW WELL TO THE SOUTH. SATELLITE SHOWING
SCATTERED CUMULUS DEVELOPING OVER THE MOUNTAINS. THIS WILL LIKELY
CONTINUE THROUGH SUNSET THEN DIMINISH. OTHERWISE UPPER LEVEL RIDGE
WILL PROVIDE MAINLY CLEAR SKIES OVERNIGHT INTO MONDAY MORNING.
LOWS TONIGHT ON THE COOL SIDE WITH MID 30S TO MID 40S. AN UPPER
LEVEL TROUGH WILL BE APPROACHING THE WEST COAST MONDAY. SOUTHERLY
FLOW ALOFT WILL DEVELOP WITH AN INCREASE IN INSTABILITY. EXPECT
SOME CUMULUS DEVELOPMENT OVER THE MOUNTAINS IN THE AFTERNOON.
MODELS CONTINUE TO INDICATE A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS OVER THE OREGON CASCADES LATE AFTERNOON INTO THE
EVENING. WARMER TOMORROW WITH HIGHS IN THE MID 70S TO MID 80S. BY
TUESDAY THE TROUGH AXIS AND COLD FRONT WILL BE ALONG THE COAST.
ADDITIONAL INSTABILITY AND MOISTURE SHOULD RESULT IN A BETTER
CHANCE OF SHOWERS AND THUNDERSTORMS ESPECIALLY BY AFTERNOON AND
EVENING. ON WEDNESDAY THE TROUGH AND COLD FRONT ARE MOVING THROUGH
THE FORECAST AREA WITH SHOWERS AND THUNDERSTORMS LIKELY. MODELS
ARE INDICATING THE POSSIBILITY OF A LARGE AREA OF STRATIFORM RAIN
DURING THE DAY. IF THIS WERE TO DEVELOP IT WOULD LIKELY DIMINISH
THE THREAT OF THUNDERSTORMS DUE TO HEAVIER CLOUD COVER AND COOLER
TEMPS. 94

LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY...WEDNESDAY AN
OFFSHORE TROUGH WILL BE SPLITTING AS AN ELONGATED FRONT SLOWLY
CROSSES THE CASCADES. SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER
EASTERN WASHINGTON AND OREGON IN THE MOIST AND UNSTABLE SOUTHERLY
FLOW AHEAD OF THIS SYSTEM. INSTABILITY WILL DECREASE WITH THE LOSS
OF DAYTIME HEATING...SO THUNDERSTORMS WILL DECREASE DURING THE
EVENING. A CLOSED LOW WILL DEVELOP IN THE SOUTHERN HALF OF THE
TROUGH AND DRIFT SOUTHEAST ACROSS CALIFORNIA THURSDAY AND FRIDAY.
EXPECT SHOWERS TO PERSIST OVER THE AREA WITH THE BROAD TROUGH BUT
THUNDERSTORMS COVERAGE SHOULD BE LIMITED TO THE MOST UNSTABLE
LOCATION/TIMES...CENTRAL TO NORTHEAST OREGON DURING THE AFTERNOON
AND EVENING. FRIDAY AFTERNOON THROUGH SATURDAY A RIDGE WILL BUILD
OVER WASHINGTON. HOWEVER...SOUTHEAST FLOW AROUND THE LOW IN
CALIFORNIA MAY KEEP SHOWERS FROM CENTRAL TO NORTHEAST OREGON WHILE
DRIER CONDITIONS SPREAD INTO EASTERN WASHINGTON. SOME MODELS
CONTINUE TO SPIN MOISTURE INTO CENTRAL AND NORTHEAST OREGON
SUNDAY...BUT OTHERS KEEP THE MOISTURE FAR ENOUGH SOUTH TO SUGGEST IT
MAY DRY OUT IN NORTHEAST OREGON SATURDAY NIGHT OR SUNDAY. COONFIELD



&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  44  80  47  81 /   0   0  10  10
ALW  47  80  50  81 /   0   0  10  10
PSC  45  84  46  83 /   0   0  10  10
YKM  46  84  48  79 /   0   0  10  20
HRI  44  83  45  83 /   0   0  10  10
ELN  43  82  46  77 /   0   0  10  20
RDM  35  79  43  75 /   0  10  20  30
LGD  41  76  42  76 /   0   0  10  10
GCD  40  76  40  76 /   0   0  10  20
DLS  46  86  52  76 /   0   0  10  30

&&

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

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

$$

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