Strong Wind in Oregon, March 29, 2012

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1030 AM PDT THU MAR 29 2012

UPDATED AVIATION DISCUSSION

.UPDATE...THE NEXT DISTURBANCE IS PUSHING THROUGH THE AREA THIS
MORNING AND WILL CONTINUE TO INFLUENCE THE WEATHER OVER THE AREA
THROUGH THE DAY AND INTO TONIGHT. RAIN IS BEING REPORTED BELOW 3000
FEET IN THE EAST SLOPES OF THE WASHINGTON CASCADES AS WELL AS ACROSS
THE MOUNTAINS OF NORTHEAST OREGON BELOW ABOUT 5000 FEET. MUCH OF THE
COLUMBIA BASIN AND CENTRAL OREGON IS CURRENTLY BEING RAINSHADOWED
THIS MORNING. EXPECT THE RAIN TO INCREASE ACROSS THE AREA DURING THE
DAY AS MOISTURE CONTINUES TO STREAM INTO THE AREA. AMOUNTS ALONG THE
FOOTHILLS MAY BE LIGHTER DUE TO THE DOWNSLOPE SOUTHERLY FLOW OFF THE
BLUE MOUNTAINS. THIS SOUTHERLY PRESSURE GRADIENT WILL ALSO LEAD TO
WINDY CONDITIONS IN THE GRANDE RONDE VALLEY WHERE A WIND ADVISORY
HAS BEEN ISSUED FOR THE LADD AND PYLES CANYON AREA UNTIL LATER THIS
MORNING. WINDS WILL DROP BELOW ADVISORY FOR THE AFTERNOON...BUT
STILL REMAIN BREEZY TO WINDY. THE REST OF THE AREA WILL SEE BREEZY
TO WINDY CONDITIONS BY THIS AFTERNOON. CURRENT FORECAST LOOKS TO BE
ON TRACK. DMH

&&

.AVIATION DISCUSSION...18Z TAFS...DETERIORATING CONDITIONS ARE
EXPECTED AGAIN TODAY AS ANOTHER WEATHER SYSTEM MOVES INTO THE
PACIFIC NORTHWEST. THIS WILL RESULT IN INCREASING CHANCES OF RAIN
TODAY AND TONIGHT AT ALL TAF LOCATIONS. CEILINGS MAY LOWER TO MVFR
AT TIMES DUE MAINLY TO LOWERED CEILINGS...THOUGH VISIBILITY MAY ALSO
BE REDUCED IN THE HEAVIER SHOWERS. WINDS WILL INCREASE FROM THE
SOUTH TO SOUTHWEST WITH THE STRONGEST WINDS IN CENTRAL OREGON WHICH
MAY SEE WIND SPEEDS IN THE 20 TO 30 KT RANGE WITH HIGHER GUSTS TO
AROUND 40 KTS. THE WINDS WILL THEN SLOWLY DIMINISH TONIGHT AS
PRESSURE GRADIENTS WEAKEN A BIT. THE STRONGEST WINDS WILL OCCUR FROM
ABOUT 18Z TODAY UNTIL 00Z THIS AFTERNOON AND WILL BE DECREASING
AFTER 00Z.

&&

.PREV DISCUSSION... /ISSUED 255 AM PDT THU MAR 29 2012/

SHORT TERM...TODAY THROUGH SATURDAY. SPRING IS DEFINITELY
HERE...AND THE WET AND WINDY WEATHER WILL CONTINUE THROUGH THE SHORT
TERM.  MILD TEMPERATURES ARE EXPECTED THROUGH FRIDAY NIGHT BUT A
COLD FRONT ON SATURDAY WILL BRING COOL AND UNSETTLED CONDITIONS.
CURRENTLY...THERE IS A DEEP LOW PRESSURE SYSTEM LOCATED NW OF
VANCOUVER ISLAND THAT IS FORCING BANDS OF MOISTURE INTO THE PACIFIC
NW AND IS BRINGING WIDESPREAD PRECIPITATION WEST OF THE CASCADES
EARLY THIS MORNING.   PRECIPITATION WILL SPREAD EAST AND THROUGHOUT
THE FORECAST AREA LATER THIS MORNING.  WARM AIR ADVECTION ALOFT IS
ALSO ALLOWING SNOW LEVELS TO RISE.  BASED ON SURFACE
OBSERVATIONS...SNOW LEVELS ARE AROUND 3500 FEET IN SOUTH CENTRAL
WASHINGTON SLOPING UP TO 5000 FEET IN CENTRAL OREGON.  SNOW LEVELS
WILL RISE AN ADDITIONAL 500-1000 FEET THIS AFTERNOON AND TONIGHT.
THE VERY MOIST W-SW FLOW ALOFT WILL RESULT IN PERIODS OF RAIN AND
HIGH ELEVATION SNOW THROUGH FRIDAY MORNING.  THE HYDROLOGY
DISCUSSION PROVIDES DETAILS ON RIVER AND STREAM RISES.

THE WESTERLY FLOW OFF THE EASTERN PACIFIC WILL BUCKLE ON FRIDAY AS
TWO LOWS DEVELOP ALONG THE BOTTOM OF THE TROUGH BETWEEN 130W-140W.
THE 00Z GFS AND ECMWF ARE MUCH STRONGER AND SLIGHTLY SLOWER THAN THE
NAM WITH THE OVERALL SYSTEM. THE GFS/ECMWF HAVE THE BEST RUN-TO-RUN
CONTINUITY SO WILL THROW OUT THE NAM.  A WELL-ORGANIZED OCCLUDED
FRONT WILL DEVELOP OFF THE OREGON COAST...AND A MOIST WARM FRONT
WILL BRING AREAWIDE PRECIPITATION LATE FRIDAY NIGHT AND SATURDAY
MORNING.  THIS WILL BE FOLLOWED BY A COLD FRONT AND ITS ASSOCIATED
UPPER LEVEL TROUGH ON SATURDAY.  COOLER AND UNSTABLE CONDITIONS CAN
BE EXPECTED.  ISOLATED THUNDERSTORMS ARE ALSO POSSIBLE SATURDAY
AFTERNOON.

IT WILL BE WINDY TODAY AND AGAIN ON FRIDAY.  A WIND ADVISORY WAS
ISSUED FOR THE LADD AND PYLES CANYONS OF THE GRANDE RONDE VALLEY IN
EFFECT FROM 3 AM THROUGH 11 AM THIS MORNING.  BASED ON SURFACE
GRADIENTS...BELIEVE THIS WILL BE A LOW END ADVISORY WITH SUSTAINED
WINDS APPROACHING 30 MPH THIS MORNING. WINDS WILL NEED TO BE
MONITORED IN NORTH CENTRAL OREGON AND THE EAST SLOPES OF THE OREGON
CASCADES TODAY...ESPECIALLY THIS MORNING.  LOCAL WIND GUSTS UP TO 45
MPH ARE EXPECTED.  MOUNTAIN GRAVITY WAVES ARE LIKELY ALONG THE
OREGON CASCADES THIS MORNING...AND THERE IS ALWAYS A POTENTIAL FOR A
VERTICALLY PROPAGATING WAVE TO REACH THE SURFACE.  WINDY CONDITIONS
CAN ALSO BE EXPECTED ON FRIDAY.  WISTER

LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...NOT MUCH CHANGE IS
EXPECTED FROM PREVIOUS FORECASTS WITH A PROGRESSIVE WEATHER PATTERN
CONTINUING WITH FREQUENT WEATHER SYSTEMS TO CROSS THE REGION. WHILE
ONE SYSTEM WILL BE DEPARTING THE AREA SATURDAY EVENING THE NEXT
SYSTEM WILL BE MOVING INLAND VERY QUICKLY BEHIND IT. HOWEVER...IT
LOOKS TO BE WEAKER THAN THE DEPARTING SYSTEM SATURDAY NIGHT. THEN A
STRONGER SYSTEM WILL MOVE INTO THE PACIFIC NORTHWEST BY MONDAY AND
MONDAY NIGHT. THE TRACK OF THE SURFACE AND UPPER LOWS ARE BEGINNING
TO SHOW SIGNS OF TAKING A MORE NORTHERLY TRACK LEAVING MOSTLY JUST
THE WARM AND COLD FRONTS TO MOVE ACROSS THE FORECAST AREA. THIS WILL
RESULT IN MORE OF A SHOWERY PATTERN...WITH POSSIBLE AFTERNOON AND
EVENING THUNDERSTORMS. THERE MAY BE A LINGERING THUNDERSTORM OR TWO
OVER THE NORTHEAST MOUNTAINS AND FOOTHILLS EARLY SATURDAY EVENING AS
THAT SYSTEM DEPARTS THE AREA. WITH THE LOWS TAKING A MORE NORTHWARD
TRACK THIS WILL ALSO TEND TO KEEP THE FORECAST AREA IN A WARMER
ATMOSPHERE...AS WELL AS MORE UNSTABLE (UNSTABLE MAINLY IN THE
AFTERNOONS AND EVENINGS). TIMING OF INDIVIDUAL STORMS WILL BE
DIFFICULT DUE TO THE MANY WEATHER SYSTEMS MOVING IN SO CLOSE TO EACH
OTHER. THE MODELS ALSO DIVERGE MORE FROM ABOUT TUESDAY ONWARD...
ENOUGH TO DECREASE FORECAST CONFIDENCE. AS SUCH AM NOT PLANNING MUCH
CHANGE BEYOND DAY 4...BUT IN ANY CASE IT WILL CONTINUE TO BE A WET
AND UNSETTLED PATTERN THROUGHOUT THE EXTENDED PERIOD. 88

HYDROLOGY...AS STATED IN THE SHORT TERM DISCUSSION...THERE WILL BE
INCREASING SNOW LEVELS AND AREAWIDE PRECIPITATION THROUGH FRIDAY
NIGHT.  24-HOUR PRECIPITATION AMOUNTS AROUND 0.25-0.50 OF AN INCH
ARE FORECAST THROUGH FRIDAY MORNING...THEN AN ADDITIONAL 0.5 INCH TO
1.5 INCHES POSSIBLE FRIDAY MORNING THROUGH SATURDAY MORNING.  RIVERS
HAVE RESPONDED WELL TO RECENT RAINFALL AND SNOW MELT RUNOFF...BUT
SHARP RISES ARE LIKELY OVER THE NEXT SEVERAL DAYS.  RIVERS AND
STREAMS COULD SWELL TO NEAR BANKFULL AND MINOR SMALL STREAM FLOODING
IS POSSIBLE.  WISTER

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  56  45  59  45 /  70  50  70  70
ALW  58  47  61  46 /  70  50  70  70
PSC  61  49  64  45 /  80  40  60  60
YKM  54  39  57  38 /  80  50  60  60
HRI  60  47  63  45 /  80  50  60  70
ELN  54  38  56  38 /  90  50  70  60
RDM  55  42  60  38 /  80  70  80  50
LGD  51  45  54  38 /  80  60  70  70
GCD  54  43  55  40 /  80  50  70  50
DLS  54  44  58  42 /  80  70  80  80

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...WIND ADVISORY UNTIL 11 AM PDT THIS MORNING FOR LADD AND PYLES
     CANYONS IN THE ORZ049.

WA...NONE.
&&

THREAT INDEX
TODAY : GREEN
FRIDAY : GREEN
SATURDAY : GREEN

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

84/

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
1044 AM PDT THU MAR 29 2012

UPDATED TO REMOVE WIND ADVISORY

ORZ041-042-044-049-050-502-503-505>509-WAZ024-026>030-520-521-
301215-
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-
1044 AM PDT THU MAR 29 2012

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

.DAY ONE...TODAY AND TONIGHT

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

SURGES OF MOISTURE IN A MOIST WEST TO SOUTHWEST FLOW ALOFT WILL
BRING PERIODS OF RAIN AND HIGH ELEVATION SNOW TODAY AND TONIGHT. SNOW
LEVELS WILL BE HIGH (AROUND 5000 FEET) WITH THE EXCEPTION OF THE
EAST SLOPES OF THE WASHINGTON CASCADES THIS MORNING WHERE SNOW
LEVELS WILL REMAIN AROUND 3000 FEET THIS MORNING THEN WILL
INCREASE TO 4000 FEET LATER TODAY. THERE WILL BE PERIODS OF HEAVY
SNOW WEST OF EASTON ALONG INTERSTATE 90 THIS MORNING. RAIN AND
SNOW MELT RUNOFF WILL RESULT IN SHARP RISES ALONG AREA RIVERS AND
STREAMS. A HYDROLOGIC OUTLOOK (PDXESFPDT) PROVIDES DETAILS ON HIGH
WATER LEVELS AND A POTENTIAL FOR MINOR FLOODING.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

OCCASIONALLY WET AND WINDY WEATHER WILL CONTINUE THROUGH THE
MIDDLE OF NEXT WEEK. A SERIES OF PACIFIC FRONTS WILL AFFECT THE
REGIONS WEATHER WITH RAIN AND MOUNTAIN SNOW AT TIMES. A FEW
THUNDERSTORMS ARE POSSIBLE ON SATURDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME.

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.