Severe Thunderstorm Warning 35, NWS Pendleton, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OREGON
200 PM PDT WED AUG 4 2004

.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT. THUNDERSTORMS HAVE
DEVELOPED ACROSS CENTRAL AND NE OREGON THIS AFTERNOON AND SHOULD
INCREASE IN AREAL COVERAGE AND INTENSITY THROUGH THE LATE AFTERNOON
AND EVENING HOURS.  STORM PREDICTION CENTER HAS ISSUED A SEVERE
THUNDERSTORM WATCH FOR CENTRAL AND NE OREGON AND SE WASHINGTON
THROUGH 8 PM.  WIND SHEAR IS IMPRESSIVE...AND ORGANIZED CONVECTION
IS LIKELY ONCE A WAVE IN NORTHERN CALIFORNIA LIFTS NORTHEASTWARD AND
ENHANCES LIFT. A SECONDARY WAVE ROTATING ALONG THE BOTTOM OF AN
UPPER TROUGH OFF THE EASTERN PACIFIC WILL SWING NE AND ACROSS THE
REGION TONIGHT FOR SCATTERED NOCTURNAL THUNDERSTORMS.  TOUGH
DECISION ON WHAT WILL HAPPEN ONCE THIS WAVE EXITS THE REGION
THURSDAY MORNING.  WHILE THE ETA RUN SHOWS A BREAK IN PRECIPITATION
THURSDAY AFTERNOON...THE GFS SHOWS ANOTHER WEAK WAVE MOVING EAST OF
THE CASCADES FOR POSSIBLE SHOWERS AND THUNDERSTORMS.  THE ETA AND
GFS DIFFER SIGNIFICANTLY WITH THE STRENGTH OF THE TROUGH AS IT
PUSHES EAST OF THE CASCADES FRIDAY AND FRIDAY NIGHT.  THE GFS IS
MUCH STRONGER WITH THE TROUGH AND IS THE MOST PREFERRED.  HAVE A
DIFFICULT TIME BELIEVING THE TROUGH WILL DAMPEN AS ADVERTISED BY THE
ETA.  THEREFORE...HAVE CONTINUED THE CHANCE OF SHOWERS AND
THUNDERSTORMS FRIDAY AND FRIDAY NIGHT...ESPECIALLY IN OUR WA ZONES.
SMITH

.LONG TERM...SATURDAY THROUGH WEDNESDAY...A RIDGE OF HIGH PRESSURE
WILL BEGIN TO BUILD OVER THE PACIFIC NORTH ON SATURDAY...AND WILL
STRENGTHEN THROUGH EARLY NEXT WEEK.  AS A RESULT...DRY WEATHER IS
EXPECT.  A GRADUAL WARMING TREND WILL ALSO OCCUR...WITH TEMPERATURES
ONCE AGAIN PUSHING INTO THE 90S ACROSS MUCH OF THE REGION BY
MONDAY.  PALMER

&&

.PRELIMINARY POINT TEMPS/POPS...
PENDLETON (AIRPORT) 064 083 056 082 / 030 030 020 010
WALLA WALLA         067 083 058 083 / 030 030 020 010
TRI-CITIES          065 085 054 085 / 040 020 010 010
YAKIMA              061 084 052 082 / 040 030 010 020
HERMISTON           066 084 054 084 / 040 020 010 010
ELLENSBURG          060 081 054 078 / 040 030 010 020
REDMOND             052 080 047 080 / 030 020 010 010
LA GRANDE           056 081 049 082 / 030 030 020 010
JOHN DAY            057 083 051 083 / 030 030 020 010
THE DALLES          064 081 059 081 / 040 030 010 010
&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...SEVERE THUNDERSTORMS WATCH UNTIL 8 PM FOR
     DESCHUTES...CROOK...WHEELER..GRANT...WALLOWA...
     UNION...UMATILLA...MORROW...GILLIAM...SHERMAN...AND
     WASCO COUNTIES.
WA...SEVERE THUNDERSTORM WATCH UNTIL 8 PM FOR WALLA WALLA AND
     COLUMBIA COUNTIES.
&&

85

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OREGON
100 PM PDT WED AUG 4 2004

ORZ041>050-WAZ024>030-051200-
NORTH CENTRAL OREGON-CENTRAL OREGON-LOWER COLUMBIA BASIN (OR)-
FOOTHILLS OF THE BLUE MOUNTAINS (OR)-BLUE MOUNTAINS-JOHN DAY BASIN-
OCHOCO-JOHN DAY HIGHLANDS-GRANDE RONDE VALLEY-WALLOWA COUNTY-
EASTERN COLUMBIA RIVER GORGE (WA)-
EAST SLOPES OF THE SOUTHERN CASCADES-KITTITAS VALLEY-YAKIMA VALLEY-
LOWER COLUMBIA BASIN (WA)-FOOTHILLS OF THE BLUE MOUNTAINS (WA)-
NORTHWEST BLUE MOUNTAINS-
100 PM PDT WED AUG 4 2004

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

.DAY ONE...TODAY AND TONIGHT

A SEVERE THUNDERSTORM WATCH BOX IS IN EFFECT FOR
     EASTERN COLUMBIA RIVER GORGE (WA), EASTERN COLUMBIA RIVER GORGE
     (WA), EAST SLOPES OF THE SOUTHERN CASCADES, KITTITAS VALLEY,
     YAKIMA VALLEY, LOWER COLUMBIA BASIN (WA), FOOTHILLS OF THE BLUE
     MOUNTAINS (WA), NORTHWEST BLUE MOUNTAINS, EASTERN COLUMBIA RIVER
     GORGE (OR), NORTH CENTRAL OREGON, CENTRAL OREGON, LOWER COLUMBIA
     BASIN (OR), FOOTHILLS OF THE BLUE MOUNTAINS (OR), BLUE
     MOUNTAINS, JOHN DAY BASIN, OCHOCO-JOHN DAY HIGHLANDS, GRANDE
     RONDE VALLEY, WALLOWA COUNTY

STRONG THUNDERSTORMS
     EASTERN COLUMBIA RIVER GORGE (WA), EASTERN COLUMBIA RIVER GORGE
     (WA), EAST SLOPES OF THE SOUTHERN CASCADES, KITTITAS VALLEY,
     YAKIMA VALLEY, LOWER COLUMBIA BASIN (WA), FOOTHILLS OF THE BLUE
     MOUNTAINS (WA), NORTHWEST BLUE MOUNTAINS, EASTERN COLUMBIA RIVER
     GORGE (OR), NORTH CENTRAL OREGON, CENTRAL OREGON, LOWER COLUMBIA
     BASIN (OR), FOOTHILLS OF THE BLUE MOUNTAINS (OR), BLUE
     MOUNTAINS, JOHN DAY BASIN, OCHOCO-JOHN DAY HIGHLANDS, GRANDE
     RONDE VALLEY, WALLOWA COUNTY

SCATTERED SHOWERS AND THUNDERSTORMS ARE BEGINNING TO DEVELOP ACROSS
EASTERN OREGON AND EASTERN WASHINGTON...WHICH WILL PERSIST THROUGH
THIS EVENING. MOISTURE AND INSTABILITY COMBINED WITH STRONG MID
LEVEL WIND SHEAR WILL RESULT IN ORGANIZED THUNDERSTORMS CAPABLE OF
PRODUCING LARGE HAIL AND DAMAGING WINDS.

THE STORM PREDICTION CENTER IN NORMAN, OKLAHOMA, HAS ISSUED A SEVERE
THUNDERSTORM WATCH UNTIL 8 PM PDT FOR CENTRAL AND NORTHEASTERN
OREGON AND PORTIONS OF SOUTHEAST WASHINGTON...INCLUDING THE
FOLLOWING LOCATIONS
BEND...CONDON...ENTERPRISE...FOSSIL...HEPPNER...HERMISTON...JOHN
DAY...LA GRANDE...MADRAS...MAUPIN...PENDLETON...PRINEVILLE...
SENECA...THE DALLES AND WASCO IN OREGON AS WELL AS WALLA
WALLA...WALLULA...WAITSBURG...AND DAYTON IN WASHINGTON.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THUNDERSTORMS THURSDAY
          EASTERN COLUMBIA RIVER GORGE (WA), EAST SLOPES OF THE
          SOUTHERN CASCADES, KITTITAS VALLEY, YAKIMA VALLEY, LOWER
          COLUMBIA BASIN (WA), FOOTHILLS OF THE BLUE MOUNTAINS (WA),
          NORTHWEST BLUE MOUNTAINS, EASTERN COLUMBIA RIVER GORGE
          (OR), LOWER COLUMBIA BASIN (OR), FOOTHILLS OF THE BLUE
          MOUNTAINS (OR), BLUE MOUNTAINS, JOHN DAY BASIN, OCHOCO-JOHN
          DAY HIGHLANDS, GRANDE RONDE VALLEY, WALLOWA COUNTY

ISOLATED TO SCATTERED COVERAGE OF THUNDERSTORMS WILL CONTINUE ON
THURSDAY...ENDING IN THE EASTERN COLUMBIA RIVER GORGE...YAKIMA
VALLEY...AND COLUMBIA BASIN BY AFTERNOON.  THESE STORMS ARE EXPECTED
TO REMAIN BELOW SEVERE LEVELS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL LIKELY BE REQUIRED THIS AFTERNOON AND
EVENING.

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

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

WWW.WRH.NOAA.GOV/PENDLETON/FORECAST/HWOGRAPHICS/HWOGRAPHICS.PHP

ALL LETTERS IN THE ABOVE URL ARE LOWER CASE...EXCEPT THE G IN
HWOGRAPHICS AND THE G IN HWOGRAPHICS.PHP.