Area Forecast Discussion
Issued by NWS Pendleton, OR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KPDT 211740 AAB
AFDPDT

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
940 AM PST FRI NOV 21 2014

UPDATED AVIATION DISCUSSION

.UPDATE...THE LATEST SFC OBS WERE CONTINUING TO SHOW AREAS OF FOG
OVER THE BASIN WHERE THE DENSE FOG ADVISORY REMAINS IN EFFECT THIS
MORNING. OTHERWISE ANOTHER STORM WILL TAKE AIM ON THE PACNW AND
SPREAD CLOUDS AND SHOWERS TO THE ENTIRE AREA. SOME COLD AIR IS
FORECAST TO REMAIN TRAPPED ALONG THE EAST SLOPES OF THE WA CASCADES
WHICH IS EXPECTED TO PRODUCE A MIX OF FROZEN PCPN THAT HAS PROMPTED
A WINTER WEATHER ADVISORY FOR TODAY AND THIS EVENING. ELSEWHERE
PRESSURE GRADIENTS TIGHTEN PRODUCING WINDY CONDITIONS OVER PORTIONS
OF THE GRANDE RONDE VALLEY LATER TODAY AND TONIGHT. OTHER THAN SOME
MINOR ADJUSTMENTS TO SKY COVER AND TEMPS AND THE PRESENT SHORT TERM
FORECAST REMAINS ON TRACK FOR NOW.

&&

.AVIATION DISCUSSION...18Z TAFS...CONDITIONS WILL REMAIN BELOW VFR
AT KDLS...KPDT...KYKM...KALW AND KPSC IN FOG THROUGH AT LEAST EARLY
AFTERNOON. THERE MAY BE SOME IMPROVEMENT THEREAFTER...BUT AS RAIN
MOVES INTO THE AREA EXPECT CONDITIONS TO ONCE AGAIN DETERIORATE DUE
TO LOW CEILINGS. KRDM AND KBDN COULD REMAIN VFR...BUT THEIR CEILINGS
WILL LIKELY DROP AS WELL. RAIN WILL CONTINUE THROUGH TONIGHT ALONG
WITH MVFR/IFR VISIBILITIES IN FOG AND HAZE. WINDS WILL INCREASE THIS
AFTERNOON AND TONIGHT WITH THE STRONGEST WINDS AFTER 12Z SATURDAY
AND GUSTS OF 20 TO 30 KTS.  82

&&

.PREV DISC... /ISSUED 319 AM PST FRI NOV 21 2014/

SHORT TERM...TODAY THROUGH SATURDAY. CLEARING SKIES OVERNIGHT HAS
ALLOWED FAIRLY WIDESPREAD LOW CLOUDS AND FOG TO DEVELOP ACROSS THE
REGION. WITH INCREASING MID AND HIGH LEVEL CLOUDS TODAY THE FOG AND
STRATUS WILL BE SLOW TO CLEAR. DENSE FOG LIKELY ALONG THE BLUE
MOUNTAIN FOOTHILLS. NEXT SYSTEM APPROACHING THE PACIFIC NORTHWEST
HAS A GOOD DEAL OF MOISTURE WITH IT. RAIN WILL OVERSPREAD THE AREA
THIS AFTERNOON AND CONTINUE TONIGHT. SOME HEAVIER RAIN IS LIKELY
OVER THE CASCADES AND NORTHEAST OREGON MOUNTAINS. COLDER AIR ALONG
THE WASHINGTON EAST SLOPES WILL RESULT IN A MIX OF RAIN, FREEZING
RAIN AND SNOW. A WINTER WEATHER ADVISORY HAS BEEN ISSUED FOR THIS.
THE COLD FRONT MOVES THROUGH OVERNIGHT. THIS WILL LOWER SNOW LEVELS
ACROSS THE REGION INTO SATURDAY HOWEVER PRECIPITATION WILL BE
DIMINISHING. THIS FRONTAL PASSAGE WILL BREAK THE LOW LEVEL
INVERSIONS CLEARING OUT THE FOG AND STRATUS AND ENDING THE AIR
STAGNATION EVENT. STRONGER WINDS ALOFT COMBINED WITH THE SURFACE
GRADIENTS WILL CREATE BREEZY TO WINDY CONDITIONS LATER TODAY INTO
SATURDAY. 94

LONG TERM...SATURDAY NIGHT THROUGH FRIDAY...ACTIVE WEATHER IS IN
STORE FOR MUCH OF THE PERIOD AS SEVERAL STORM SYSTEMS WILL MOVE
ACROSS THE REGION ESPECIALLY PRIOR TO THURSDAY. MODELS ARE IN
RELATIVE AGREEMENT THROUGH WEDNESDAY THEN DIVERGE AFTERWARDS WITH
THE GFS TRENDING TOWARD COLDER WEATHER AND THE ECMWF MILDER WEATHER
WITH AN UPPER LEVEL RIDGE. FOR SATURDAY NIGHT RAIN AND HIGHER
MOUNTAIN SNOW WILL BEGIN TO TAPER OFF AS A SHORTWAVE TROUGH EXITS
THE AREA TO THE EAST. HOWEVER ANOTHER SYSTEM WILL BE ON ITS HEELS ON
SUNDAY WITH A GOOD CHANCE FOR MOSTLY RAIN AREAWIDE. RAIN WILL TAPER
OFF ON MONDAY AS HEIGHTS BEGIN TO RISE WITH A BUILDING RIDGE OF HIGH
PRESSURE. RAIN COULD RETURN TO THE REGION TUESDAY AND WEDNESDAY
ESPECIALLY NORTH ALONG WITH WARM TEMPERATURES. HIGHS IN THE LOWER
ELEVATIONS COULD REACH AT LEAST THE LOWER 50S BOTH DAYS. IF THE GFS
MODEL IS CORRECT IT COULD TURN NOTICEABLY COOLER FOR THURSDAY AND
FRIDAY AS MORE ARCTIC AIR BEGINS TO SPILL SWWD ACROSS THE CANADIAN
ROCKIES. FOR NOW HAVE JUST SHOWED A COOLING TREND BUT NOT TO THE
EXTENT THAT THE GFS WOULD INDICATE. IT WILL BE BREEZY TO LOCALLY
WINDY OFF AND ON SUNDAY THROUGH WEDNESDAY LOWER ELEVATIONS AND
EXPOSED RIDGES. 78

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  42  37  45  36 /  30  90  50  30
ALW  41  37  46  39 /  30  90  50  40
PSC  39  36  48  38 /  30  90  30  10
YKM  36  29  45  32 /  70  90  30  10
HRI  40  36  46  37 /  30  90  40  20
ELN  35  29  45  32 /  80  90  30  10
RDM  44  37  44  26 /  70  90  50  40
LGD  41  38  41  33 /  20  90  70  50
GCD  43  33  40  31 /  30  90  70  40
DLS  37  35  45  38 /  80 100  50  30

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL NOON PST TODAY
     ORZ041-044-050-505-507-508-510-511.

     DENSE FOG ADVISORY UNTIL 11 AM PST THIS MORNING ORZ507.

     WIND ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM PST SATURDAY
     ORZ049.

WA...AIR STAGNATION ADVISORY UNTIL NOON PST TODAY WAZ024-026>029-521.

     WINTER WEATHER ADVISORY UNTIL 10 AM PST SATURDAY WAZ520.

     DENSE FOG ADVISORY UNTIL 11 AM PST THIS MORNING WAZ029.

     WINTER WEATHER ADVISORY UNTIL 4 AM PST SATURDAY WAZ026.

&&

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

$$

97/82





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.