Severe Thunderstorm Warning 29, NWS Pendleton, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OREGON
820 AM PDT MON AUG 2 2004

.SHORT TERM...NEW ETA IS IN AND ITS INDICATING THE MAIN FOCUS FOR
CONVECTION WITH THE POSSIBILITY OF THE STORMS BECOMING STRONG WAS
NEAR AND OVER THE WALLOWA AREA WHERE SPC HAS THE SLIGHT RISK.
THUNDERSTORMS SHOULD DEVELOP IN A LARGER AREA WHICH SHUD ENCOMPASS
AREAS SUCH AS REDMOND/JOHN DAY AS WELL WHERE THE FOCUS OF ANY STRONG
CONVECTION SHOULD BE PRIMARILY HAIL. AREAS NEAR WALLOWA WHERE THERE IS
A LOWER LFC HEIGHT AND LARGER CAPE THE STORMS COULD BE STRONGER.
HOWEVER MY CONFIDENCE IN THE MODELS WAS LIMITED SINCE BOTH THE
ETA/GFS HAD QPF AMOUNTS ALREADY ACROSS THE OREGON
AREA(PDT/RDM/5JO/BKE) AT 18Z. IN THE MEANTIME...FAIRLY STRONG CAP
ALOFT SHUD INHIBIT CONVECTION UNTIL AROUND 21Z. NO CHANGES TO THE
FORECAST EXPECTED AT THIS TIME.

&&

.PRELIMINARY POINT TEMPS/POPS...
PENDLETON (AIRPORT) 093 061 088 / 020 030 010
WALLA WALLA         094 065 088 / 020 020 010
TRI-CITIES          097 062 090 / 010 020 010
YAKIMA              092 059 088 / 010 020 010
HERMISTON           094 061 089 / 010 020 010
ELLENSBURG          089 060 084 / 010 020 010
REDMOND             089 048 085 / 030 030 010
LA GRANDE           090 053 086 / 020 030 020
JOHN DAY            092 053 088 / 020 030 020
THE DALLES          088 064 086 / 020 020 010
&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE PENDLETON OREGON
500 AM PDT MON AUG 2 2004

ORZ041>050-WAZ024>030-031200-
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-
500 AM PDT MON AUG 2 2004

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

.DAY ONE...TODAY AND TONIGHT

SLIGHT RISK OF SEVERE THUNDERSTORMS
     LOWER COLUMBIA BASIN (WA), FOOTHILLS OF THE BLUE MOUNTAINS (WA),
     NORTHWEST BLUE MOUNTAINS, LOWER COLUMBIA BASIN (OR), FOOTHILLS
     OF THE BLUE MOUNTAINS (OR), BLUE MOUNTAINS, JOHN DAY BASIN,
     OCHOCO-JOHN DAY HIGHLANDS, GRANDE RONDE VALLEY, WALLOWA COUNTY

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY AND TONIGHT.
THIS RISK IS TO THE EAST OF A LINE FROM SOUTH CENTRAL CROOK COUNTY
OREGON...TO ARLINGTON OREGON...TO HANFORD WASHINGTON. THIS INCLUDES
THE CITIES OF JOHN DAY...BOARDMAN...HERMISTON...PENDLETON...
WALLA WALLA...THE TRI-CITIES...LA GRANDE AND ENTERPRISE. THE MAIN
THREATS FROM THESE STORMS WILL BE STRONG...GUSTY WINDS AND LARGE
HAIL.

AN UPPER LEVEL LOW PRESSURE SYSTEM OVER NORTHWEST CALIFORNIA THIS
MORNING WILL MOVE NORTHEAST ACROSS EASTERN OREGON AND WASHINGTON
THROUGH TONIGHT. THIS SYSTEM WILL TAP A MOIST AND UNSTABLE AIR MASS
THAT IS NOW IN PLACE ACROSS THE REGION RESULTING IN THUNDERSTORM
DEVELOPMENT.

STRONG THUNDERSTORMS
     EASTERN COLUMBIA RIVER GORGE (WA), EAST SLOPES OF THE SOUTHERN
     WASHINGTON CASCADES, KITTITAS VALLEY, YAKIMA VALLEY, EASTERN
     COLUMBIA RIVER GORGE (OR), NORTH CENTRAL OREGON, CENTRAL OREGON

THE SAME UPPER LEVEL STORM SYSTEM THAT HAS RESULTED IN THE SLIGHT
RISK OF SEVERE THUNDERSTORMS WILL ALSO GENERATE THUNDERSTORMS ALONG
EAST SLOPES OF THE OREGON AND WASHINGTON CASCADES. THESE STORMS WILL
ALSO PRODUCE GUSTY WINDS AND HAIL...BUT ARE NOT EXPECTED TO REACH
SEVERE LEVELS AT THIS TIME.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THUNDERSTORMS TUESDAY
          EAST SLOPES OF THE SOUTHERN CASCADES, NORTHWEST BLUE
          MOUNTAINS, BLUE MOUNTAINS, JOHN DAY BASIN, OCHOCO-JOHN DAY
          HIGHLANDS, GRANDE RONDE VALLEY, WALLOWA COUNTY

THUNDERSTORMS WEDNESDAY
          EAST SLOPES OF THE SOUTHERN CASCADES, NORTHWEST BLUE
          MOUNTAINS, BLUE MOUNTAINS, OCHOCO-JOHN DAY HIGHLANDS,
          WALLOWA COUNTY

SOUTHWEST FLOW WITH EMBEDDED DISTURBANCES WILL PERSIST THROUGH MID
WEEK. THIS PATTERN WILL CAUSE THE DEVELOPMENT OF THUNDERSTORMS TO
CONTINUE OVER PORTIONS OF EASTERN OREGON AND SOUTHEAST WASHINGTON.
THE BEST CHANCES FOR THUNDERSTORM ACTIVITY WILL BE OVER THE
MOUNTAINS ON TUESDAY AND WEDNESDAY. HIGH PRESSURE WILL THEN BUILD
OVER THE REGION FOR DRIER CONDITIONS FRIDAY THROUGH SUNDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED TODAY AND TONIGHT FOR STRONG OR
POSSIBLY SEVERE THUNDERSTORMS FOR MUCH OF CENTRAL...NORTH CENTRAL
AND NORTHEAST OREGON...AS WELL AS SOUTH CENTRAL AND SOUTHEAST
WASHINGTON.

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.