Area Forecast Discussion
Issued by NWS Pendleton, OR

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000
FXUS66 KPDT 241001
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
300 AM PDT THU APR 24 2014

.SHORT TERM...TODAY THROUGH SATURDAY AFTERNOON...UPPER LEVEL TROUGH
DIGGING SOUTH OFFSHORE WILL BACK FLOW ALOFT TO SOUTH TODAY JUST
AHEAD OF A COLD FRONT. AIR MASS WILL BECOME UNSTABLE BY LATE THIS
MORNING SO THERE IS A SLIGHT CHANCE OF THUNDERSTORMS THIS AFTERNOON
AND THIS EVENING. A COLD FRONT WILL MOVE THROUGH THE FORECAST AREA
THIS AFTERNOON AND ACT AS A TRIGGER FOR ISOLATED THUNDERSTORMS IN
THE EASTERN OREGON AND SOUTHEAST WASHINGTON. ALSO A SLIGHT CHANCE OF
AFTERNOON THUNDERSTORMS OVER BLUE MOUNTAINS FRIDAY AFTERNOON ALONG
WITH A CHANCE OF SHOWERS. FRIDAY LOOKS TO BE DRY DUR TO HIGH
PRESSURE.  POLAN

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...SATURDAY NIGHT WILL
SEE AN UPPER LEVEL TROUGH MOVING OFF TO THE EAST WHILE ANOTHER
SYSTEM IN A MOIST AND PROGRESSIVE WESTERLY FLOW WILL BE MOVING INTO
THE AREA. THIS WILL GIVE US A CHANCE OF RAIN WITH THE MOUNTAINS
HAVING A RAIN/SNOW MIX SATURDAY NIGHT THROUGH SUNDAY. THE MOISTURE
WILL BEGIN TO TAPER OFF SUNDAY NIGHT WITH JUST A SLIGHT CHANCE OF
RAIN IN THE LOWER ELEVATIONS AND A CHANCE OF RAIN AND SNOW SHOWERS
IN THE MOUNTAINS ABOVE 4500 FEET. MONDAY WILL SEE RIDGING BUILDING
OVER THE AREA AND THE LOWER ELEVATIONS WILL BE DRY WHILE A SLIGHT
CHANCE OF RAIN AND SNOW SHOWERS WILL CONTINUE IN THE MOUNTAINS.
MODELS ARE IN AGREEMENT IN HAVING THE RIDGE REMAIN OVER THE AREA
THROUGH AT LEAST WEDNESDAY NIGHT WHICH WILL GIVE US A PERIOD OF DRY
WEATHER AND A WARMING TREND. THE GFS WANTS TO BRING AN UPPER LOW TO
THE CANADIAN BORDER AREA, POSSIBLY ON THURSDAY, THOUGH THE TIMING
CHANGES ON EACH OF THE LAST COUPLE OF RUNS WHILE THE ECMWF DOES NOT
HAVE THIS FEATURE. IF THIS SYSTEM PROVES TO BE REAL, THE GFS IS
USUALLY TOO FAST BRING THEM IN THIS FAR OUT IN THE LONG TERM PERIOD
SO HAVE KEPT THE FORECAST DRY THOUGH POPS WERE RAISED TO AROUND 10
PERCENT IN THE WASHINGTON CASCADES. HIGHS WILL BE IN THE MID 50S TO
MID 60S WITH MID 40S TO MID 50S IN THE MOUNTAINS SUNDAY AND MONDAY
THEN RISE TO THE 70S WITH 60S IN THE MOUNTAINS TUESDAY THROUGH
THURSDAY. PERRY

&&

.AVIATION...PREVIOUS DISCUSSION...06Z TAFS...THERE MAY BE BRIEF
PERIODS OF MVFR AND POSSIBLY EVEN IFR CONDITIONS TONIGHT DUE TO
LOWERED CIGS AND SHOWERS REDUCING VISIBILITY. HOWEVER MOST OF THE
TIME VFR CONDITIONS WILL PREVAIL. WINDS WILL RANGE FROM 5 TO 15 KTS
OVERNIGHT AND THEN WILL INCREASE TO 10 TO 20 KTS WITH LOCALLY 15 TO
25 KTS ON THURSDAY AS A COLD FRONT MOVES ACROSS THE CWA AND MIXES
DOWN STRONGER WINDS FROM ALOFT WITH CONVECTIVE RAIN SHOWERS AND
POSSIBLY EVEN THUNDERSTORMS. THE THUNDERSTORM THREAT WILL PRIMARILY
BE AT KPDT AND KALW. 88

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  58  39  57  38 /  80  60  60  20
ALW  58  42  58  42 /  90  60  70  30
PSC  64  43  63  41 /  60  20  20  10
YKM  59  35  60  36 /  50  10  20  10
HRI  62  42  61  39 /  60  40  40  20
ELN  57  36  59  35 /  60  10  20  10
RDM  55  30  49  27 /  50  60  60  20
LGD  53  36  52  35 /  80  70  80  50
GCD  54  34  46  30 /  80  70  90  40
DLS  60  40  60  40 /  60  40  40  30

&&

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

THREAT INDEX
TODAY : GREEN
FRIDAY : GREEN
SATURDAY : 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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