AREA FORECAST DISCUSSION

 
 FXUS66 KPDT 100536
 AFDPDT
 
 AREA FORECAST DISCUSSION
 NATIONAL WEATHER SERVICE PENDLETON OR
 930 PM PST TUE FEB 9 2010
 
 .SHORT TERM...A WEAK UPPER RIDGE WILL REMAIN OVER THE PACIFIC 
 NORTHWEST TONIGHT. IR SATELLITE SHOWS A FAIR AMOUNT OF CLOUD COVER
 THIS EVENING...SIMILAR TO LAST EVENING. 00Z SOUNDINGS FROM ACROSS 
 THE REGION HAVE AN INVERSION AT 8-10K FEET. THIS IS TRAPPING THE 
 LOW LEVEL MOISTURE WITH MOST OBSERVATION SITES INDICATING CEILINGS 
 AT 5-9K. THERE ARE SOME BREAKS EVIDENT ON SATELLITE SO WILL GO WITH 
 A MOSTLY CLOUDY FORECAST TONIGHT. LOW TEMPERATURES SHOULD BE COLDER 
 THAN LAST NIGHT ESPECIALLY WITH THE BREAKS IN THE CLOUDS. WILL 
 FORECAST 20S TO LOWER 30S. PATCHY FOG WILL LIKELY DEVELOP LATER 
 TONIGHT. AN APPROACHING FRONT WILL BRING INCREASING MID AND HIGH 
 LEVEL CLOUDS WEDNESDAY. THE FRONT WILL MOVE THROUGH WED NIGHT WITH A 
 GOOD CHANCE OF PRECIPITATION. THIS WILL BE FOLLOWED BY ANOTHER 
 SYSTEM THURSDAY PRODUCING ADDITIONAL RAIN AND MOUNTAIN SNOW.  94
 
 .AVIATION...06Z TAFS. SCT-BKN 040-080 TONIGHT INTO WEDNESDAY 
 MORNING. PATCHY FOG IS POSSIBLE LATE TONIGHT AND WEDNESDAY MORNING. 
 INCREASING CLOUDS IN THE AFTERNOON WITH APPROACHING WARM FRONT. RAIN 
 LIKELY FOR ALL TAF SITES WEDNESDAY EVENING WITH CEILINGS 020-040. 
 SURFACE WINDS LESS THAN 10KT.  94
 
 &&
 
 .PREV DISCUSSION... /ISSUED 230 PM PST TUE FEB 9 2010/ 
 
 SHORT TERM...TONIGHT THROUGH FRIDAY...HIGH PRESSURE WILL DOMINATE 
 THE AREAS WEATHER WITH DRY CONDITIONS AND SOME PATCHY FOG OVERNIGHT 
 ACROSS PORTIONS OF THE LOWER COLUMBIA BASIN AND CENTRAL OREGON ALONG 
 WITH AND AROUND MEH. THE NEXT STORM SYSTEM OVER THE EPAC WAS POISED 
 TO STRIKE OUR AREA TOMORROW. ABUNDANT MOISTURE WILL STREAM INTO THE 
 TWO STATE AREA WITH SHOWERS DEVELOPING ACROSS THE EAST SLOPES OF THE 
 WA/OR CASCADES BY AFTERNOON. THE BULK OF THIS STORM SYSTEMS MOISTURE 
 IS EXPECTED TO SPREAD INTO THE REMAINDER OF OUR AREA WEDNESDAY 
 NIGHT. SNOW LEVELS WILL REMAIN HIGH BUT WILL BRIEFLY LOWER TOMORROW 
 NIGHT TO AROUND 4K AND SOME SNOW ACCUMULATION IS POSSIBLE OVER THE 
 BLUE MOUNTAINS AND CASCADES BY THURSDAY MORNING. OTHERWISE THE STORM 
 SYSTEM WILL MOVE EAST THURSDAY NIGHT AND PCPN SHOULD DECREASE ACROSS 
 THE AREA. AS THE SYSTEM MOVES EAST THURSDAY NIGHT BREEZY 850/MBS 
 WINDS MAY MIX TOWARD THE SURFACE THURSDAY EVENING ACROSS PORTIONS OF 
 THE COLUMBIA BASIN AND IN AND NEAR LGD. FINALLY A THIRD STORM SYSTEM 
 WILL BRING SHOWERS TO THE TWO STATE AREA FRIDAY.  
 
 LONG TERM...FRIDAY NIGHT THROUGH TUESDAY...A RIDGE OF HIGH PRESSURE 
 WILL START TO BUILD INTO THE PACIFIC NORTHWEST ON FRIDAY NIGHT. 
 THEREFORE...DRIER CONDITIONS CAN BE EXPECTED ON SATURDAY...BUT 
 MOUNTAIN SHOWERS COULD PERSIST DUE TO MOIST ONSHORE FLOW. A WEAK 
 FRONT WILL MOVE INTO THE REGION ON SUNDAY...BRINGING PRECIPITATION 
 TO MUCH OF THE AREA. HOWEVER...SNOW LEVELS WILL REMAIN HIGH ENOUGH 
 TO PRECLUDE SIGNIFICANT SNOW ACCUMULATIONS BELOW 5000 FEET. ANOTHER 
 TRANSITORY RIDGE WILL DEVELOP ON MONDAY...ALLOWING THE RAIN AND SNOW 
 SHOWERS TO DIMINISH. PROGRESSIVE WESTERLY FLOW WILL THEN SEND 
 ANOTHER WET WEATHER DISTURBANCE THROUGH THE REGION ON TUESDAY. WINDS 
 WILL GENERALLY BE LIGHT THROUGH THE PERIOD...BUT LOCALLY BREEZY 
 WINDS MAY DEVELOP AS EACH SYSTEM PASSES...ESPECIALLY IN THE GRANDE 
 RONDE VALLEY AND LADD/PYLES CANYONS. TEMPERATURES WILL REMAIN MILDER 
 THAN NORMAL.  82 
 
 &&
 
 .PRELIMINARY POINT TEMPS/POPS...
 PDT  30  48  36  48 /   0  10  40  50 
 ALW  31  48  35  46 /   0  10  40  40 
 PSC  30  47  35  49 /   0  10  40  40 
 YKM  29  46  31  45 /  10  30  50  40 
 HRI  31  48  37  49 /   0  10  40  40 
 ELN  29  44  30  42 /  10  30  50  40 
 RDM  26  49  34  52 /  10  30  60  50 
 LGD  26  41  31  45 /  10  10  40  60 
 GCD  28  44  32  49 /  10  10  50  50 
 DLS  33  49  36  50 /  10  40  60  50 
 
 &&
 
 .PDT WATCHES/WARNINGS/ADVISORIES...
 OR...NONE.
 WA...NONE.
 &&
 
 THREAT INDEX
 WEDNESDAY : GREEN
 THURSDAY : GREEN
 FRIDAY : GREEN
 
 GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
 YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
 RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
 
 FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
 WWW.WEATHER.GOV/PENDLETON
 
 $$
 
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