Flooding in Washington, January 15 to 20, 2011

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
303 AM PST SAT JAN 15 2011

UPDATED AVIATION DISCUSSION

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT.  IT WILL REMAIN
UNSEASONABLY WARM THROUGH THE SHORT TERM PERIOD.  BOTH AFTERNOON
HIGHS AND OVERNIGHT LOWS WILL BE ABOUT 10-20 DEGREES ABOVE NORMAL.
HIGH SNOW LEVELS ARE RESULTING IN RAPID SNOWMELT.  IN ADDITION...A
VERY MOIST WARM FRONT WILL BRING WIDESPREAD RAIN TONIGHT...PUSHING
SNOW LEVELS TO ABOVE 7000 FEET.  SATELLITE SHOWS A GOOD MOISTURE TAP
ASSOCIATED WITH THE FRONT.  STRONG OROGRAPHIC LIFT CAN BE EXPECTED
ALONG THE CASCADES AND THE BLUE MOUNTAINS IN A MOIST WESTERLY FLOW
ALOFT...AND RAINFALL AMOUNTS OF 1-2 INCHES CAN BE EXPECTED TONIGHT
THROUGH SUNDAY IN OUR EASTERN SIDE OF THE CASCADES AND THE BLUES.
THE HYDROLOGY SECTION OF THIS DISCUSSION WILL PROVIDE DETAILS ON THE
HYDROMETEOROLOGICAL CONCERNS ASSOCIATED WITH THIS SYSTEM.  THE
STRONG WESTERLY FLOW WILL PROVIDE SOME RAIN SHADOWING OFF THE
CASCADES BY SUNDAY MORNING...AND THE COLUMBIA BASIN AND SURROUNDING
VALLEYS AS WELL AS THE COLUMBIA DESCHUTES PLATEAU WILL NOT SEE AS
MUCH RAINFALL AND WILL SEE DRIER CONDITIONS SUNDAY AFTERNOON AND
SUNDAY NIGHT.  A COLD FRONT ON SUNDAY NIGHT WILL LOWER SNOW LEVELS
DOWN TO AROUND 5000 FEET.  STRONG WINDS ALOFT AND A TIGHT PRESSURE
GRADIENT WILL ALSO ACCOMPANY THE COLD FRONT...THUS IT WILL BE WINDY
IN MANY AREAS.  WIND ADVISORIES MAY BE NEEDED UPON FURTHER REVIEW OF
THE MODELS...PARTICULARLY IN AND AROUND THE COLUMBIA BASIN.  JOHNSON

.LONG TERM...MONDAY THROUGH FRIDAY...A RIDGE OF HIGH PRESSURE WILL
BUILD IN THE EAST PACIFIC WITH A NORTHWEST FLOW OVER THE REGION.
WINDS WILL DECREASE AND PRECIPITATION CHANCES WILL DECREASE ACROSS
THE REGION AS THE WEEKEND SYSTEM MOVES OFF TO THE EAST. SOME SHOWERS
WILL BE POSSIBLE IN THE BLUE MOUNTAINS DUE TO UPSLOPE CONDITIONS.
THE NEXT DISTURBANCE WILL INFLUENCE THE WEATHER IN THE AREA ON
TUESDAY. MODELS CONTINUE TO DISAGREE WITH THE STRENGTH OF THIS
SYSTEM WITH THE GFS NOW STRONGER THAN THE EUROPEAN. HAVE KEPT A
MIDDLE OF THE ROAD FORECAST OF A CHANCE OF PRECIPITATION ACROSS THE
AREA ON TUESDAY AND A COOLING TREND IN THE TEMPERATURES INTO
WEDNESDAY. AS THE DISTURBANCE MOVES OFF TO THE EAST... THE RIDGE
WILL REBUILD OVER THE EAST PACIFIC AND PUSH THE MOISTURE STREAM
NORTH OF THE REGION. THIS WILL LEAD TO DRIER CONDITIONS FOR THE
AREA. HAVE KEPT A SLIGHT CHANCE OF PRECIPITATION FOR THE MOUNTAINS
WITH A NORTHWEST UPSLOPE FLOW...THOUGH IF MODELS CONTINUE TO
INDICATE THE ACTIVE WEATHER BEING PUSHED NORTHWARD...PRECIPITATION
CHANCES WILL DROP FOR THE MOUNTAINS ON THURSDAY AS WELL. THE RIDGE
WILL BECOME MORE FLAT AS A STRONGER DISTURBANCE MOVES THROUGH THE
FLOW AND WILL MOVE INTO THE FORECAST AREA ON FRIDAY...BRINGING A
RETURN TO PRECIPITATION. WITH COOLER TEMPERATURES...SNOW LEVELS WILL
BE LOWER AND THUS A CHANCE OF RAIN AND SNOW WILL BE POSSIBLE FOR THE
HIGHER TERRAIN BY THE END OF NEXT WEEK. DMH

&&

.AVIATION...12Z TAFS....VFR CONDITIONS ARE EXPECTED INTO SATURDAY
MORNING WITH MID TO HIGH LEVEL CLOUDS INCREASING. THE NEXT SYSTEM
WILL BRING RAIN TO THE REGION STARTING AFTER 15/19Z AT KDLS AND
SPREAD EAST TO THE REST OF THE TAF LOCATIONS BY MID AFTERNOON.
CEILINGS AND VISIBILITIES WILL LOWER WITH THE RAIN WITH MVFR TO IFR
CONDITIONS POSSIBLE. EXPECT THE RAIN TO CONTINUE INTO THE OVERNIGHT
AND SUNDAY MORNING HOURS. DMH

&&

.HYDROLOGY...MODERATE TO HEAVY RAIN WILL SPREAD ACROSS THE REGION
TONIGHT AND SUNDAY.  THERE HAVE BEEN SHARP RISES ALONG MANY OF THE
RIVERS AND STREAMS...AND ADDITIONAL SNOWMELT RUNOFF AND HEAVY RAIN
MAY FORCE WATER LEVELS ABOVE BANKFULL.  FLOOD WATCHES HAVE BEEN
ISSUED FOR THE EAST SLOPES OF THE WASHINGTON CASCADES...THE BLUE
MOUNTAINS...AND THE BLUE MTN FOOTHILLS.  THE NACHES...KLICKITAT...
UMATILLA...JOHN DAY...AND WALLA WALLA RIVERS ARE JUST A FEW OF THE
LARGER RIVERS THAT ARE RUNNING HIGH AND WILL BE CLOSELY MONITORED.

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  57  46  57  42 /  60  90  70  50
ALW  60  47  60  44 /  50  90  70  60
PSC  61  46  60  43 /  40  90  70  20
YKM  53  40  52  37 /  30  90  50  30
HRI  55  46  56  42 /  50  90  70  30
ELN  48  39  47  35 /  30  90  50  40
RDM  54  44  56  39 /  60  90  70  50
LGD  49  42  49  40 /  50  90  70  60
GCD  48  43  47  40 /  50  90  60  60
DLS  54  48  55  43 /  60 100  70  50

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FLOOD WATCH FROM THIS EVENING THROUGH MONDAY MORNING
     ORZ049-050-502-507.

WA...FLOOD WATCH FROM THIS EVENING THROUGH MONDAY MORNING
     WAZ029-030-520.

&&

THREAT INDEX
TODAY : GREEN
SUNDAY : YELLOW
MONDAY : YELLOW

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

85/84/84

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
510 AM PST SAT JAN 15 2011

ORZ041-042-044-049-050-502-503-505>509-WAZ024-026>030-520-521-
161300-
EASTERN COLUMBIA RIVER GORGE OF OREGON-NORTH CENTRAL OREGON-
LOWER COLUMBIA BASIN OF OREGON-GRANDE RONDE VALLEY-WALLOWA COUNTY-
NORTHERN BLUE MOUNTAINS OF OREGON-
SOUTHERN BLUE MOUNTAINS OF OREGON-JOHN DAY BASIN-OCHOCO-
JOHN DAY HIGHLANDS-
FOOTHILLS OF THE NORTHERN BLUE MOUNTAINS OF OREGON-
FOOTHILLS OF THE SOUTHERN BLUE MOUNTAINS OF OREGON-
EAST SLOPES OF THE OREGON CASCADES-
EASTERN COLUMBIA RIVER GORGE OF WASHINGTON-KITTITAS VALLEY-
YAKIMA VALLEY-LOWER COLUMBIA BASIN OF WASHINGTON-
FOOTHILLS OF THE BLUE MOUNTAINS OF WASHINGTON-
NORTHWEST BLUE MOUNTAINS OF WASHINGTON-
EAST SLOPES OF THE WASHINGTON CASCADES-SIMCOE HIGHLANDS-
510 AM PST SAT JAN 15 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL AND NORTHEAST OREGON
AS WELL AS SOUTH CENTRAL AND SOUTHEAST WASHINGTON.

.DAY ONE...TODAY AND TONIGHT

FLOOD WATCH
     EAST SLOPES OF THE WASHINGTON CASCADES, EASTERN COLUMBIA RIVER
     GORGE OF WASHINGTON, KITTITAS VALLEY, FOOTHILLS OF THE BLUE
     MOUNTAINS OF WASHINGTON, NORTHWEST BLUE MOUNTAINS OF
     WASHINGTON, GRANDE RONDE VALLEY, WALLOWA COUNTY, FOOTHILLS OF
     THE NORTHERN BLUE MOUNTAINS OF OREGON, NORTHERN BLUE MOUNTAINS
     OF OREGON

A MOIST WARM FRONT WILL BRING MODERATE TO HEAVY RAIN TO EASTERN
WASHINGTON AND EASTERN OREGON TONIGHT.  HIGH SNOW LEVELS AND
UNSEASONABLY WARM TEMPERATURES ARE CONTRIBUTING TO RAPID SNOW MELT.
THE COMBINATION OF SNOW MELT RUNOFF AND HEAVY RAIN WILL LEAD TO SHARP
RISES ON RIVERS AND STREAMS.  THE AREAS LISTED ARE UNDER A FLOOD
WATCH BEGINNING THIS EVENING AND CONTINUING THROUGH MONDAY MORNING.
FOR DETAILS...REFER TO THE NWS PRODUCT...PDXFFAPDT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

FLOOD WATCH SUNDAY
     EAST SLOPES OF THE WASHINGTON CASCADES, EASTERN COLUMBIA RIVER
     GORGE OF WASHINGTON, KITTITAS VALLEY, FOOTHILLS OF THE BLUE
     MOUNTAINS OF WASHINGTON, NORTHWEST BLUE MOUNTAINS OF
     WASHINGTON, GRANDE RONDE VALLEY, WALLOWA COUNTY, FOOTHILLS OF
     THE NORTHERN BLUE MOUNTAINS OF OREGON, NORTHERN BLUE MOUNTAINS
     OF OREGON

AS STATED EARLIER...A FLOOD WATCH IS IN EFFECT FOR THE AREAS LISTED
THROUGH MONDAY MORNING.  WIDESPREAD RAIN WILL CONTINUE THROUGH
SUNDAY MORNING THEN WILL DECREASE IN COVERAGE SUNDAY AFTERNOON AND
SUNDAY NIGHT.  HOWEVER...THE CASCADES AND THE BLUE MOUNTAINS WILL
CONTINUE TO RECEIVE MODERATE TO HEAVY RAIN THROUGH MONDAY MORNING.

SNOW LEVELS WILL LOWER TO AROUND 4500-5000 FEET SUNDAY NIGHT AND
MONDAY THEN DOWN TO NEAR 2500-3000 FEET ON MONDAY NIGHT. OCCASIONAL
RAIN AND MOUNTAIN SNOW CAN BE EXPECTED THROUGH THE MID WEEK.  DRIER
CONDITIONS ARE EXPECTED WEDNESDAY AND THURSDAY BEFORE THE NEXT
SYSTEM ARRIVES ON FRIDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED DUE TO FLOODING TONIGHT THROUGH
MONDAY MORNING.

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

GRAPHICAL FORECASTS OF WEATHER HAZARDS OUT TO SEVEN DAYS
ARE DISPLAYED ON THE WORLD WIDE WEB AT:

WWW.WRH.NOAA.GOV/PDT/CURRENTHAZARDS/HWO.HTML

ALL LETTERS IN THE ABOVE URL ARE LOWER CASE.