Strong Wind in Oregon, October 18, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
1000 AM PDT THU OCT 18 2007

UPDATED AVIATION DISCUSSION

.SHORT TERM...TODAY AND TONIGHT...A BAND OF PRECIPITATION ASSOCIATED
WITH A WARM FRONT IS CURRENTLY MOVING NORTHEASTWARD ACROSS NORTHEAST
OREGON AND EASTERN WASHINGTON. RAINFALL AMOUNTS OF UP TO ONE QUARTER
INCH CAN BE EXPECTED IN SOME LOCATIONS. ADDITIONALLY...STRONG WINDS
ALOFT ARE FORECAST TO MIX DOWN TO THE SURFACE THIS
AFTERNOON...CREATING BREEZY CONDITIONS WITH WINDS OF 20-30 MPH OVER
MUCH OF THE AREA. STRONGER WINDS OF 25-35 MPH WITH GUSTS TO 45 MPH
MAY BE POSSIBLE ALONG THE RIDGE TOPS OF THE OREGON CASCADES AND
PORTIONS OF CENTRAL AND NORTH CENTRAL OREGON...CAUSING POTENTIALLY
HAZARDOUS DRIVING CONDITIONS. A WIND ADVISORY IS IN EFFECT FROM 10
AM TO 7 PM IN THESE AREAS. THE WINDS SHOULD FALL BELOW ADVISORY
LEVEL TONIGHT AS MORE STABLE AIR ASSOCIATED WITH AN APPROACHING COLD
FRONT MOVES INTO THE REGION. PRECIPITATION IS ALSO EXPECTED TO
DIMINISH THIS EVENING DUE TO DOWNSLOPE FLOW OFF OF THE CASCADES.
POPS WILL THEN INCREASE ONCE AGAIN TOMORROW MORNING WITH THE
APPROACH OF A SECOND STRONG STORM SYSTEM.  TRIMARCO

&&

.AVIATION...A WARM FRONT IS SPREADING PRECIPITATION ACROSS THE AREA.
MVFR CONDITIONS IN LOW CEILINGS AND VISIBILITIES ARE POSSIBLE WITH
THE HEAVIER SHOWERS THIS MORNING...OTHERWISE THE AREA WILL BE UNDER
VFR CONDITIONS. A BRIEF BREAK IN PRECIPITATION WILL OCCUR THIS
AFTERNOON BEFORE THE NEXT ROUND OF PRECIPITATION WILL RETURN TONIGHT
INTO FRIDAY. WINDS WILL INCREASE THIS AFTERNOON...WITH STRONG WINDS
EXPECTED AT RIDGETOP LEVELS AND ALOFT. THESE WINDS HAVE THE
POTENTIAL TO CREATE STRONG LOW-LEVEL WIND SHEAR. SURFACE WINDS WILL
INCREASE TO 20 TO 30 MPH WITH GUSTS TO 40 MPH THIS AFTERNOON INTO
THE EVENING. DK

.PREV DISCUSSION... /ISSUED 658 AM PDT THU OCT 18 2007/

SHORT TERM...TODAY THROUGH FRIDAY...A VERY ENERGETIC WESTERLY FLOW
ALOFT WILL BRING A 110 KNOT JET STREAM INTO THE INTERIOR PACIFIC
NORTHWEST TODAY. A SHARP AND DEEPENING SURFACE PRESSURE TROUGH ALONG
THE IMMEDIATE LEEWARD SIDE OF THE OREGON CASCADES WILL DEVELOP THIS
MORNING AND CONTINUE THROUGH THIS AFTERNOON. THIS SURFACE PRESSURE
TROUGH WILL INTERACT WITH THE UPPER LEVEL JET AND ALLOW STRONG WINDS
ALOFT TO DESCEND AND MIX DOWN TO THE SURFACE IN CENTRAL AND NORTH
CENTRAL OREGON TODAY RESULTING IN VERY WINDY CONDITIONS. THE JET
WILL PERSIST OVER THE REGION TONIGHT AND THEN SLOWLY MOVE ACROSS THE
FORECAST AREA ON FRIDAY. WINDS IN THE JET CORE WILL BE STRONGER ON
FRIDAY AND RESULT IN MORE WIDESPREAD BREEZY TO VERY WINDY CONDITIONS.
THE STRONGEST SURFACE WINDS WILL OCCUR IN CENTRAL AND NORTH CENTRAL
OREGON DUE TO THE INTERACTION BETWEEN THE JET STREAM AND A STRONG
SURFACE LOW PRESSURE TROUGH IN CENTRAL AND NORTH CENTRAL OREGON.
A WIND ADVISORY IS IN EFFECT FOR THESE AREAS FROM 10 AM THIS MORNING
UNTIL 7 PM THIS EVENING.

OTHERWISE...ABUNDANT MOISTURE ASSOCIATED WITH A WARM FRONT AND AN
UPPER LEVEL SHORT WAVE WILL MOVE ACROSS THE INTERIOR PACIFIC
NORTHWEST TODAY FOR RAIN LIKELY...ESPECIALLY THIS MORNING...WITH
RAIN TAPERING OFF TO JUST A CHANCE OF RAIN IN THE AFTERNOON IN NORTH
CENTRAL OREGON AND IN CENTRAL OREGON EAST OF HIGHWAY 97 DUE TO
DOWNSLOPE WINDS IMMEDIATELY EAST OF THE CENTRAL AND NORTH CENTRAL
OREGON CASCADES. THE DOWNSLOPE WINDS WILL SPREAD EASTWARD THIS
EVENING AND SUPPRESS PRECIPITATION OVER  A LARGE AREA WITH JUST A
CHANCE OF RAIN IN THE FAR EASTERN MOUNTAINS. ANOTHER RIPPLE OF
ENERGY ALONG THE JET STREAM WILL MOVE RAPIDLY INTO THE FORECAST
LATER TONIGHT BRING WARM FRONTAL OVERRUNNING PRECIPITATION AND THUS
INCREASING THE CHANCES FOR RAIN TO LIKELY (60 PERCENT) EVERYWHERE...
EXCEPT IN THE LOWER COLUMBIA BASIN OF WASHINGTON WHERE A GOOD CHANCE
OF RAIN WILL OCCUR. THE JET STREAM WILL USHER IN ANOTHER FAST MOVING
UPPER LEVEL SHORT WAVE WITH ASSOCIATED DYNAMIC LIFT AND A COLD FRONT
SWEEPING ACROSS THE FORECAST AREA ON FRIDAY MORNING FOR RAIN AT
TIMES IN SOUTHEAST WASHINGTON AND RAIN LIKELY IN CENTRAL...NORTH
CENTRAL AND NORTHEAST OREGON.  POLAN

LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...UPPER LEVEL TROUGH
WILL MOVE THROUGH FRIDAY NIGHT AND SATURDAY. SATURDAY NIGHT AN UPPER
LEVEL RIDGE STARTS TO BUILD NEAR THE COAST. A WARM FRONT WILL MOVE
THROUGH THE RIDGE SATURDAY NIGHT AND SUNDAY. NOT CONFIDENT IN HOW
MUCH OPPOSING CONDITIONS OF SLOWLY BUILDING RIDGE AND ISENTROPIC
LIFT FROM WARM FRONT WILL IMPACT PRECIPITATION...BUT KEPT SLIGHT
CHANCE IN BASIN AND CHANCE TO LIKELY ELSEWHERE. BY SUNDAY NIGHT THE
BUILDING RIDGE WILL MOVE INLAND WITH DRYING CONDITIONS. MONDAY AND
TUESDAY WILL BE DRY UNDER THE INFLUENCE OF THE RIDGE. A WEAK FRONT
MAY MOVE THROUGH TUESDAY NIGHT OR WEDNESDAY...BUT EXPECT ANY
PRECIPITATION TO BE LIGHT AS ATMOSPHERE INITIALLY DRY.  COONFIELD

&&

.PRELIMINARY POINT TEMPS/POPS...
PDT  56  45  58  41 /  60  60  80  20
ALW  55  46  59  44 /  70  60  90  20
PSC  58  44  62  43 /  70  50  90  20
YKM  53  37  57  35 /  80  60 100  20
HRI  58  44  61  41 /  60  60  80  20
ELN  49  37  55  36 /  80  60 100  20
RDM  56  40  56  33 /  70  70  50  30
LGD  49  41  57  37 /  70  70  70  20
GCD  52  43  54  37 /  70  70  60  30
DLS  55  43  59  44 /  80  70  80  20

&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...WIND ADVISORY UNTIL 7 PM PDT THIS EVENING FOR ORZ042-043.

WA...NONE.
&&

TI:YGG
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
82/84

HAZARDOUS WEATHER OUTLOOK...UPDATE
NATIONAL WEATHER SERVICE PENDLETON OR
1045 AM PDT THU OCT 18 2007

UPDATED TO ADD WIND ADVISORY FOR GRANDE RONDE VALLEY

ORZ041>044-049-050-501>506-WAZ024-026>030-501-502-191300-
EASTERN COLUMBIA RIVER GORGE OF OREGON-NORTH CENTRAL OREGON-
CENTRAL OREGON-LOWER COLUMBIA BASIN OF OREGON-GRANDE RONDE VALLEY-
WALLOWA COUNTY-FOOTHILLS OF THE BLUE MOUNTAINS OF OREGON-
NORTHERN BLUE MOUNTAINS OF OREGON-
SOUTHERN BLUE MOUNTAINS OF OREGON-
NORTHERN WHEELER AND SOUTHERN GILLIAM COUNTIES-JOHN DAY BASIN-
OCHOCO-JOHN DAY HIGHLANDS-
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-
EAST SLOPES OF THE CENTRAL CASCADES OF WASHINGTON-
EAST SLOPES OF THE SOUTHERN CASCADES OF WASHINGTON-
1045 AM PDT THU OCT 18 2007

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

.DAY ONE...TODAY AND TONIGHT

STRONG WIND
     NORTHWEST BLUE MOUNTAINS, NORTH CENTRAL OREGON, CENTRAL
     OREGON, GRANDE RONDE VALLEY, WALLOWA COUNTY, NORTHERN BLUE
     MOUNTAINS OF OREGON, SOUTHERN BLUE MOUNTAINS OF OREGON,
     OCHOCO-JOHN DAY HIGHLANDS

AN UPPER LEVEL JET STREAM WITH WINDS OF 125 MPH AT 30000 FEET WILL
MOVE INTO THE INTERIOR PACIFIC NORTHWEST TODAY. STRONG WINDS ALOFT
ASSOCIATED WITH THE JET WILL INTERACT WITH A STRONG SURFACE LOW
PRESSURE TROUGH IN CENTRAL AND NORTH CENTRAL OREGON THUS ALLOWING
STRONG WINDS ALOFT EAST OF THE CASCADE CRESTS TO DESCEND TOWARD THE
EARTHS SURFACE AND MIX DOWN TO THE GROUND. SUSTAINED WINDS OF 25 TO
35 MPH FROM THE SOUTHWEST ARE EXPECTED WITH GUSTS TO 45 MPH IN
CENTRAL AND NORTH CENTRAL OREGON AND ALSO THE GRANDE RONDE VALLEY.
THE STRONGEST WINDS WILL OCCUR ALONG RIDGE TOPS. A WIND ADVISORY IS
IN EFFECT FOR CENTRAL AND NORTH CENTRAL OREGON AND THE GRANDE RONDE
VALLEY FROM 10 AM THIS MORNING UNTIL 7 PM THIS EVENING. FOR
DETAILS SEE PRODUCT PDXNPWPDT. ELSEWHERE...VERY WINDY CONDITIONS
WILL OCCUR TODAY IN THE HIGHER MOUNTAINS IN THE OCHOCO-JOHN DAY
HIGHLANDS...THE SOUTHERN AND NORTHERN BLUE MOUNTAINS...AND WALLOWA
COUNTY.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

THE AFOREMENTIONED JET STREAM WILL REMAIN OVER THE REGION ON FRIDAY
THUS GIVING BREEZY TO WINDY CONDITIONS. ANOTHER UPPER LEVEL SHORT
WAVE WILL GIVE THE MOUNTAINS A CHANCE OF RAIN SHOWERS ON SATURDAY
AND SUNDAY. THIS WILL BE FOLLOWED BY AN UPPER LEVEL HIGH PRESSURE
RIDGE AND DRY CONDITIONS ON MONDAY AND TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED.

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...EXCEPT THE H IN
CURRENTHAZARDS.