Area Forecast Discussion
Issued by NWS Pendleton, OR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
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 140533 AAA
AFDPDT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
935 PM PST SAT FEB 13 2016

UPDATED AVIATION DISCUSSION

.UPDATE...FORECAST ON TRACK ON ONLY MINOR UPDATES HAVE BEEN MADE.
A WESTERLY FLOW ALOFT WITH A MOISTURE TAP AS FAR WEST AS 160W IS
PRESENT ALONG THE MID LATITUDES OF THE PACIFIC AND THE PACIFIC NW.
A WARM FRONT IS BRINGING WIDESPREAD PRECIPITATION OVER WASHINGTON
AND NORTHERN OREGON THIS EVENING. EARLIER FORECAST HAD POPS IN
THE 60-80 PCT RANGE...AND POPS WERE INCREASED TO 80-100 PCT IN THE
AREAS CURRENTLY RECEIVING LIGHT TO MODERATE RAIN. THAT IS...MAINLY
ALONG THE EAST SLOPES OF THE WA CASCADES AND EAST OF THE LOWER
COLUMBIA BASIN. PRECIPITATION IS LIGHT OVER MOST OF THE LOWER
COLUMBIA BASIN AND DOWN TOWARD THE COLUMBIA DESCHUTES PLATEAU
WHERE RAIN SHADOWING IS TAKING PLACE EAST OF THE CASCADE RANGE.
SNOW LEVELS WERE INCREASED AN ADDITIONAL 300-500 FEET TONIGHT AS
WELL...AND THE LATEST FORECAST REFLECTS SNOW LEVELS AROUND
4500-5000 FEET. THERE WERE CONCERNS THAT THE BLUE MOUNTAINS AND
WALLOWA COUNTY COULD HAVE SNOW ACCUMULATIONS MEETING ADVISORY
CRITERIA...BUT THE WET BULB TEMPERATURES ARE HIGH ENOUGH THAT ANY
SNOW ACCUMULATIONS (APPROX 4-7 INCHES) TONIGHT THROUGH SUNDAY WILL
BE AT ELEVATIONS ABOVE 5000 FEET.  WISTER

&&

.AVIATION...06Z TAFS. PERIODS OF RAIN CAN BE EXPECTED THROUGH THE
PERIOD...ESPECIALLY AT KDLS, KPDT AND KALW. IN THESE
LOCATIONS...CIGS/VSBY WILL LOWER TO MVFR OR LESS AT TIMES. DUE TO A
WESTERLY FLOW ALOFT PROVIDING RAIN SHADOWING OFF THE CASCADE RANGE
AND A FLAT HIGH PRESSURE RIDGE OVER SOUTHERN OREGON...ONLY LIGHT
SHOWERS ARE EXPECTED AT THE OTHER TAF SITES WITH BETTER POTENTIAL
FOR PREVAILING VFR CONDITIONS. SW-W WINDS WILL BE 5-15 MPH BUT GUSTS
TO 20-25 MPH ARE POSSIBLE ON SUNDAY. WISTER

&&

.PREV DISCUSSION... /ISSUED 323 PM PST SAT FEB 13 2016/

SHORT TERM...TONIGHT THROUGH MONDAY...AN UPPER RIDGE CURRENTLY
OVER THE EASTERN PACIFIC WILL BEGIN TO BUILD ALONG THE WEST COAST
LATE TONIGHT INTO SUNDAY. THIS WILL CAUSE WARM AIR ADVECTION
ALOFT. THIS WARM AIR ADVECTION WILL PROVIDE ENERGY THAT WILL
ACCESS THE MOIST AIR OVER THE REGION RESULTING IN CONTINUED PRECIP
ACROSS THE REGION SUNDAY AND SUNDAY NIGHT. BEST, AND HEAVIEST,
PRECIP WILL OCCUR NEAR THE CASCADE CREST AND OVER THE INTERIOR
MOUNTAINS. THERE IS THE POTENTIAL FOR SIGNIFICANT RISES OF RIVER
FLOWING THROUGH THE WASHINGTON CASCADE EAST SLOPES. ALSO WILL SEE
WINDS INCREASE ACROSS THE REGION SUNDAY AFTERNOON CAUSING A
WARMING OF AREA TEMPERATURES. THE WINDS WILL ALSO CAUSE BETTER
MIXING AREAWIDE. THE RIDGE WILL BUILD FURTHER ON MONDAY PUSHING
THE PRECIP THREAT NORTH, WITH ONLY LIGHT PRECIP NEAR THE CASCADES
AND OVER THE BLUES AND WALLOWAS EXPECTED. CONDITIONS WILL CONTINUE
LOCALLY BREEZY AND MILD. 90

LONG TERM...A RIDGE OF HIGH PRESSURE REBUILDS OVER THE REGION
MONDAY NIGHT AND TUESDAY PUSHING MOST OF THE MOISTURE NORTH OF THE
AREA...BUT THERE MAY STILL BE SOME SHOWERS ALONG THE CASCADES...
ESPECIALLY IN WESTERN KITTITAS COUNTY. ANOTHER WEATHER SYSTEM WILL
APPROACH ON WEDNESDAY...AND THERE WILL BE A CHANCE OF MOSTLY RAIN
SHOWERS WITH SNOW LEVELS RANGING 5500 TO 7000 FEET. SNOW LEVELS WILL
THEN DECREASE ON WEDNESDAY NIGHT AND THURSDAY AS THE LOW PRESSURE
TROUGH MOVES INLAND...FALLING TO AROUND 4000 FEET. BESIDES RAIN AND
MOUNTAIN SNOW...BREEZY WINDS CAN ALSO BE EXPECTED ON THURSDAY. A
HIGH PRESSURE RIDGE THEN MOVES QUICKLY ACROSS THE REGION THURSDAY
NIGHT AND SHOWERS WILL DECREASE. THE MODELS CONTINUE TO BE IN
DISAGREEMENT FROM FRIDAY ONWARD AS THE ECMWF WANTS TO BRING ANOTHER
SYSTEM THROUGH THE AREA ON FRIDAY...WHILE THE GFS KEEPS THE MAIN
FRONT OFFSHORE UNTIL SATURDAY. HAVE THEREFORE KEPT A SLIGHT CHANCE
TO A CHANCE OF RAIN AND SNOW IN THE FORECAST THROUGH THIS PERIOD TO
ACCOUNT FOR UNCERTAINTY. TEMPERATURES WILL REMAIN ABOVE NORMAL
THROUGH NEXT WEEKEND. THE WARMEST DAYS WILL BE MONDAY AND TUESDAY
WITH HIGHS IN THE 50S AND 60S.  COBB



&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  42  58  48  64 / 100  70  50  10
ALW  45  59  50  66 / 100  70  50  10
PSC  44  58  49  66 /  80  40  20  10
YKM  35  55  42  63 /  50  20  20  10
HRI  43  59  49  66 /  80  50  30  10
ELN  35  51  42  58 /  70  20  20  10
RDM  39  56  41  62 /  50  40  30  10
LGD  38  52  46  59 /  80  80  60  20
GCD  36  55  43  60 /  80  70  40  10
DLS  42  56  48  63 /  70  50  30  20

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...AIR STAGNATION ADVISORY UNTIL 10 AM PST SUNDAY FOR WAZ026-027.

&&

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

$$

85


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