Area Forecast Discussion
Issued by NWS Pendleton, OR

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000
FXUS66 KPDT 240902
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
202 AM PDT FRI OCT 24 2014

.SHORT TERM...TODAY THROUGH SUNDAY...A BROAD UPPER TROUGH CONTINUES
OFF THE PACIFIC NORTHWEST COAST WITH WEAK WEATHER DISTURBANCES
ROTATING AROUND IT AND UP THROUGH THE CWA. THIS UPPER TROUGH IS
EXPECTED TO DIG A CLOSED UPPER LOW OFF THE COAST BY LATE FRIDAY AND
THEN WILL SWING UP THROUGH THE PACIFIC NORTHWEST ON SATURDAY AS A
WARM FRONT. THE WARM FRONT WILL PUSH A BAND OF PRECIPITATION
NORTHWARD AS THE UPPER LOW DIGS OFF THE COAST. THIS PATTERN WILL
BRING SIGNIFICANT PRECIPITATION TO THE ENTIRE CWA OVERNIGHT TONIGHT
WITH A BREAK TO OCCUR ON SATURDAY MORNING. AFTER THAT AN ASSOCIATED
COLD FRONT WITH THE LOW WILL MOVE INTO THE CWA SATURDAY AFTERNOON
AND NIGHT WITH SHOWERS CONTINUING SATURDAY NIGHT WITH AN UPPER
TROUGH PASSAGE. THIS PATTERN WILL PERSIST ON SUNDAY WITH SHOWERS
ACROSS THE CWA...ESPECIALLY THE NORTHEAST MOUNTAINS AND CASCADES.
THEN ANOTHER WEATHER SYSTEM WILL MOVE INTO THE CWA BY LATE MONDAY
WITH ONLY A BRIEF BREAK BETWEEN SYSTEMS. PRESSURE GRADIENTS TIGHTEN
UP SIGNIFICANTLY SATURDAY AFTERNOON AND NIGHT. THIS WILL RESULT IN
SIGNIFICANT WINDS WHICH HAS THE POTENTIAL TO REACH WIND ADVISORY
SPEEDS. RIGHT NOW THERE IS TOO MUCH UNCERTAINTY TO ISSUE ANY
HIGHLIGHTS ABOUT THIS BUT IT WILL BECOME WINDY IN MOST AREAS IN ANY
CASE AND WILL BE MONITORED CLOSELY. TEMPERATURES WILL STAY COOL
THROUGH THE NEXT FEW DAYS. 88

.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY. PERIODS OF RAIN AND HIGH
ELEVATION SNOW AND BREEZY WINDS ARE FORECAST THROUGH THE EXTENDED
PERIOD.  SHOWERS AND GUSTY WINDS SUNDAY EVENING WILL TAPER OFF
OVERNIGHT AS A WEAK TRANSITORY RIDGE SHIFTS EAST OF THE CASCADES.
OTHER THAN ISOLATED MOUNTAIN SHOWERS...A DRY FORECAST IS IN STORE
FOR MONDAY. THE RIDGE WILL FLATTEN CONSIDERABLY AS A STRONG WESTERLY
FLOW TAKES OVER RESULTING IN SCATTERED SHOWERS MONDAY NIGHT THROUGH
WEDNESDAY...MAINLY OVER THE MOUNTAINS. SNOW LEVELS DURING THIS TIME
WILL RANGE FROM 6000-7000 FEET.  THE DETERMINISTIC MODELS ARE ONCE
AGAIN DIVERGING BY DAY 6...AND CONFIDENCE IS LOW BASED ON THE HIGH
DEGREE OF SPREAD IN THE ENSEMBLE RUNS. THE GFS IS FARTHER NORTH AND
EAST COMPARED TO THE ECMWF OF A LARGE UPPER LEVEL TROUGH OFF THE
EASTERN PACIFIC DURING THE MID WEEK. DESPITE THE DIFFERENCES IN THE
MODELS...BOTH THE GFS AND ECMWF ARE ADVERTISING A CHANCE OF RAIN
WEDNESDAY NIGHT THROUGH THURSDAY NIGHT.  WISTER

&&

.AVIATION...06Z TAFS (PREVIOUS DISCUSSION)...THE SWATH OF RAIN THAT
AFFECTED THE TAF SITES HAS MOVED SOUTH AND EAST EAST OF THE AREA.
HOWEVER...IT WILL RETURN AS A WARM FRONT ON FRIDAY. AS A
RESULT...KBDN AND KRDM COULD START SEEING RAIN AGAIN AROUND 12Z
ALONG WITH LOWERING CEILINGS. THE RAIN AND LOWERING CEILINGS WILL
THEN PROGRESS SLOWLY NORTHWARD THROUGH THE DAY AND INTO FRIDAY
EVENING EVENTUALLY IMPACTING ALL TAF SITES. EXPECT VFR CONDITIONS
OVERNIGHT...THEN TRANSITIONING TO MVFR OR LOWER FRIDAY AND FRIDAY
NIGHT. WINDS WILL REMAIN LESS THAN 10 KTS.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  55  46  59  45 /  50  30  20  30
ALW  59  49  60  49 /  50  50  20  30
PSC  59  45  62  48 /  20  60  20  30
YKM  55  40  56  41 /  20  60  30  40
HRI  58  43  62  46 /  40  50  20  30
ELN  53  39  56  40 /  10  70  30  40
RDM  55  38  58  36 /  70  20  20  40
LGD  54  43  63  44 /  70  20  20  30
GCD  57  42  62  42 /  70  10  20  40
DLS  57  45  60  47 /  70  60  50  50

&&

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

&&

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

$$

88/85/85





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