Area Forecast Discussion
Issued by NWS Pendleton, OR

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000
FXUS66 KPDT 232143
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
243 PM PDT THU OCT 23 2014

.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT...A MOIST AND
MARGINALLY UNSTABLE ONSHORE FLOW WILL PERSIST OVER THE AREA INTO
THIS EVENING. THE MAIN MOISTURE PLUME WILL CONTINUE TO DRIFT SOUTH
AND SOUTHEAST THIS EVENING. THIS ADJUSTMENT OF THE MAIN MOISTURE
PLUME AND THE LOSS OF THE LIMITED DAYTIME HEATING WILL ALLOW THE
SHOWERS TO DECREASE OVER A GOOD PORTION OF THE AREA THIS EVENING.
THERE HAVE BEEN STRAY THUNDERSTORMS THIS AFTERNOON, MAINLY OVER AND
NEAR THE SOUTHERN BLUE MOUNTAINS. THERE SHOULD BE ENOUGH INSTABILITY
FOR A STRAY STORM TO CONTINUE EARLY IN THE EVENING OVER EXTREME
NORTHEAST OREGON AND SOUTHEAST WASHINGTON. THE MAIN MOISTURE PLUME
WILL LINGER FROM WALLOWA COUNTY SOUTHWEST THROUGH GRANT COUNTY TO
DESCHUTES COUNTY OVERNIGHT AND EXPECT SHOWERS TO PERSIST IN THESE
AREAS. A DEEPENING LOW WILL APPROACH THE WEST COAST FRIDAY. THIS LOW
WILL CAUSE THE MOISTURE PLUME TO GRADUALLY MOVE NORTH AS A WARM
FRONT FRIDAY AND FRIDAY NIGHT. WILL CONTINUE TO INDICATE VARYING
CHANCES OF RAIN OVER THE AREA DUE TO THIS WARM FRONT. THIS LOW LOOKS
MOVE INTO WESTERN WASHINGTON SATURDAY AFTERNOON THEN INTO SOUTHERN
BRITISH COLUMBIA SATURDAY EVENING. A COLD FRONT ASSOCIATED WITH THIS
LOW WOULD THEN MOVE ACROSS THE AREA LATE AFTERNOON AND EVENING ON
SATURDAY. WINDS WILL BE LOCALLY BREEZY TO WINDY SATURDAY AHEAD OF
THE FRONT. STRONGEST WINDS DURING THE DAY SATURDAY WILL BE OVER
CENTRAL OREGON AND IN THE GRANDE RONDE VALLEY. LOCALLY STRONG WINDS
MAY BE POSSIBLE SATURDAY NIGHT ACROSS THE COLUMBIA BASIN WITH AND
BEHIND THE COLD FRONT. WINDS MAY BE STRONG ENOUGH TO WARRANT
ADVISORIES, BUT WILL HOLD OFF ISSUING DUE TO THE CONTINUED
UNCERTAINTY AS TO THE TRACK AND TIMING OF THE SURFACE LOW. 90

.LONG TERM...SUNDAY THROUGH THURSDAY...THE 12Z RUNS OF THE GFS AND
ECMWF HAVE COME INTO BETTER AGREEMENT DURING THE EXTENDED PERIOD. ON
SUNDAY THE UPPER TROUGH WILL CROSS THE AREA BRINGING SNOW LEVELS
DOWN TO AROUND 4500-5000 FEET WHILE BREEZY WINDS PERSIST. YET ONLY
LIGHT SNOW ACCUMULATIONS ARE EXPECTED...AND MOUNTAIN SHOWERS WILL
DIMINISH SUNDAY NIGHT. A SHORTWAVE RIDGE WILL THEN BE OVER THE AREA
MONDAY WITH DRIER WEATHER. THE NEXT WEATHER DISTURBANCE IS FORECAST
TO ARRIVE MONDAY NIGHT BRINGING WIDESPREAD RAIN THROUGH TUESDAY.
DURING THIS TIME SNOW LEVELS SHOULD RISE BACK UP ABOVE 6000 FEET.
SNOW LEVELS WILL REMAIN HIGH THROUGH WEDNESDAY AS SHOWERS TAPER OFF
AND ANOTHER HIGH PRESSURE RIDGE MOVES IN FOR THURSDAY. WHILE THE
LATEST MODEL RUNS HAVE BEEN MORE CONSISTENT...THERE IS STILL
UNCERTAINTY DUE TO THE PROGRESSIVE NATURE OF THIS WEATHER PATTERN
AND FORECAST DETAILS ARE SUBJECT TO CHANGE. COBB

&&

.AVIATION...PREVIOUS DISCUSSION...18Z TAFS...MAINLY VFR CONDITIONS
WILL PREVAIL WITH BKN-OVC SKIES WITH BASES BETWEEN 4000-10000 FEET
AND HIGHER CLOUDS ABOVE. CEILINGS AND VISIBILITY MAY BRIEFLY LOWER
TO IFR IN AREAS OF RAIN...MAINLY NEAR KRDM AND KBDN. SW-W WINDS 8-15
KNOTS GUSTING TO 25 KNOTS ARE EXPECTED THROUGH EARLY EVENING...THEN
DIURNAL TERRAIN DRIVEN WINDS WILL PREVAIL. MID-LEVEL CLOUDS WILL
BEGIN TO THIN OUT ON FRIDAY MORNING...BUT CIRRUS SHOULD PERSIST. 82

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  45  60  44  65 /  20  30  30  20
ALW  48  61  47  66 /  20  30  40  10
PSC  47  62  45  63 /  10  10  40  20
YKM  40  55  40  57 /  20  10  60  30
HRI  45  61  43  63 /  20  20  40  20
ELN  39  57  39  57 /  20  10  70  30
RDM  39  56  38  62 /  30  70  20  20
LGD  46  58  43  64 /  60  60  20  20
GCD  43  57  42  64 /  60  60  10  20
DLS  45  58  45  60 /  20  50  50  50

&&

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

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

$$

90/82/82







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