Scientific Forecaster Discussion

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AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
350 PM PDT THU APR 17 2014

.SHORT TERM...TONIGHT THROUGH SUNDAY...A PACIFIC SYSTEM CONTINUES TO 
MOVE THROUGH THE PACIFIC NORTHWEST THIS AFTERNOON. THIS SYSTEM IS 
BRINGING DECENT PRECIP TO MOST AREAS, THOUGH THE PRECIP IS JUST NOW 
MOVING INTO THE GRANDE RONDE VALLEY AND WESTERN PORTIONS OF WALLOWA 
AND GRANT COUNTIES. PRECIP HAS BEEN LIGHT IN THE YAKIMA AND KITTITAS 
VALLEYS DUE TO DOWNSLOPE AFFECTS. TWO FRONTS ARE DISCERNIBLE WITH 
THIS SYSTEM, AN UPPER FRONT AND A SURFACE COLD FRONT. THE UPPER 
FRONT IS CURRENTLY MOVING THROUGH THE CASCADES, WHILE THE SURFACE 
COLD FRONT IS NOW NEARING THE COAST. AS SUCH, EXPECT RAIN AND HIGH 
ELEVATION SNOW TO CONTINUE INTO THE EVENING AT MOST LOCATIONS. AREAS 
IMMEDIATELY EAST OF THE CASCADE EAST SLOPES WILL SEE THE PRECIP 
DECREASE TO ISOLATED TO SCATTERED SHOWERS EARLY THIS EVENING. SNOW 
LEVELS WILL REMAIN RELATIVELY HIGH INTO THE EVENING, THEN FALL AS 
THE SURFACE COLD FRONT MOVES THROUGH. SNOW AMOUNTS, OUTSIDE OF THE 
HIGHEST ELEVATIONS, WILL BE LIGHT AS THE HEAVIEST PRECIP WILL OCCUR 
BEFORE SNOW LEVELS FALL LATE THIS EVENING AND OVERNIGHT. WINDS WILL 
BECOME WESTERLY AND INCREASE BEHIND THE COLD FRONT TONIGHT. 
CONDITIONS WILL BEGIN TO DRY OVERNIGHT BEHIND THE COLD FRONT AS 
WELL. SOME UPSLOPE INDUCED SHOWERS WILL CONTINUE ALONG AND NEAR THE 
INTERIOR MOUNTAINS, WHILE SLOP OVER SHOWERS WILL CONTINUE NEAR THE 
CASCADE CREST. BREEZY TO WINDY CONDITIONS WILL CONTINUE INTO FRIDAY, 
WHILE THE AIR MASS OVER THE REGION BECOMES INCREASINGLY DRIER. WINDS 
IN THE KITTITAS VALLEY MAY REACH TO AROUND 30 MPH SUSTAINED FRIDAY. 
AT THIS TIME AM NOT QUITE CONFIDENT ENOUGH TO GO WITH AN ADVISORY, 
AS THE STRONGEST WINDS MAY ONLY AFFECT THE NORTH SIDE OF THE VALLEY. 
AS SUCH, WILL SEE ANY LINGERING SHOWERS COME TO AN END. HIGH 
PRESSURE WILL KEEP CONDITIONS DRY FRIDAY NIGHT AND SATURDAY MORNING. 
A WEAK PACIFIC SYSTEM WILL MOVE INTO THEN ACROSS THE REGION SATURDAY 
AFTERNOON AND SATURDAY NIGHT. AT THIS TIME, EXPECT THIS SYSTEM TO 
INCREASE WINDS, WHILE PRECIP SHOULD BE LIMITED TO THE HIGHER 
TERRAIN. MOSTLY DRY CONDITIONS ARE EXPECTED ON SUNDAY. 90 

.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY NIGHT...HIGH PRESSURE 
RIDGE WILL LINGER THROUGH MONDAY NIGHT...WITH MILD TEMPERATURES 
ACROSS THE CWA. HAVE HELD ONTO A CHANCE FOR SHOWERS OVER THE 
NORTHEAST MOUNTAINS...AS MODELS STILL STRUGGLE WITH THE AMOUNT OF 
MOISTURE AHEAD OF THE NEXT COLD FRONT. DEPENDING ON THE TIME OF 
ARRIVAL COULD ALSO AFFECT WHETHER OR NOT THUNDER IS A POSSIBILITY.  
CURRENT GUIDANCE HAS THE NEXT COLD FRONT PUSHING THROUGH LATE MONDAY 
EVENING. AGAIN...DEPENDING ON HOW HIGH SURFACE DEWPOINTS GET WITH 
THE SOUTHWEST FLOW AHEAD OF THE FRONTAL SYSTEM...WILL PLAY A ROLE IN 
THE POSSIBILITY OF THUNDER MONDAY EVENING. BY TUESDAY THE UPPER 
LEVEL TROUGH WILL BE OVERHEAD...WITH SHOWERS AND COOLER TEMPERATURES 
ASSOCIATED. SPLIT FLOW WILL CONTINUE THROUGH WEDNESDAY NIGHT...WITH 
A TRANSITION BACK TO WARMER SOUTHWEST FLOW ON THURSDAY. SNOW LEVELS 
WILL RANGE FROM 4000-5000FT FOR TUESDAY AND WEDNESDAY...BEFORE 
REBOUNDING ABOVE 5000FT THURSDAY. HIGH TEMPERATURES WILL BE IN THE 
UPPER 60S TO MID 70S ON MONDAY...COOLING OFF INTO THE LOWER UPPER 
50S TO LOWER 60S TUESDAY...THEN REBOUNDING TO THE UPPER 60S BY 
THURSDAY AFTERNOON. WEBER 

&&

.AVIATION...00Z TAFS...AREAS OF MVFR WILL CONTINUE THIS EVENING AS A 
STORM SYSTEM MOVES ACROSS EASTERN WASHINGTON AND OREGON. LOCAL IFR 
CONDITIONS POSSIBLE AS WELL. WINDS WILL BE 10 TO 20 KTS...WITH GUSTS 
20 TO 30 KTS. THESE WINDS WILL STAY BREEZY THROUGH 18Z 
TOMORROW...AND WILL GRADUALLY DIMINISH 5-15KTS IN THE LAST 6 HOURS 
OF THE TAF PERIOD.  KBDN AND KRDM WINDS ARE EXPECTED TO BE A BIT 
LIGHTER AND SHOULD ONLY GUST AROUND 20 KTS.  CLOUDS SHOULD START 
BREAKING THIS EVENING AND LEAD INTO CLEARING SKIES OVERNIGHT.  BY 
06Z ALL AREAS SHOULD BE VFR. WEBER 

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  40  59  33  69 /  80  10   0  10 
ALW  42  60  38  69 /  80  10   0  10 
PSC  40  65  31  71 /  60   0   0  10 
YKM  37  63  33  65 /  20   0   0  10 
HRI  39  64  29  70 /  60   0   0  10 
ELN  37  60  32  64 /  30  10   0  10 
RDM  25  61  28  69 /  30   0   0  10 
LGD  37  57  29  68 /  80  20   0   0 
GCD  34  59  30  70 /  70  10   0  10 
DLS  42  65  35  68 /  30  10   0  10 

&&

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

THREAT INDEX
FRIDAY : GREEN
SATURDAY : GREEN
SUNDAY : 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

$$

90/89/89