Damaging Wind in Oregon, August 2, 2004

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OREGON
230 PM PDT MON AUG 2 2004

.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT. CONCERN THIS PACKAGE
IS WITH CONVECTION AND HOW STRONG STORMS WILL BECOME THIS EVENING.

ATTM...THE CAP IN PLACE ACROSS THE ENTIRE AREA EARLIER WAS ERODING.
CLOUD TOPS WERE COOLING RAPIDLY WITH SEVERAL STORMS BLOWING UP
ACROSS THE AREA. EHI VALUES WERE HIGHEST NEAR RDM AND VGP NEAR
JOHN DAY/WALLOWAS WHERE THERE IS A SLIGHT RISK. SEVERE THUNDERSTORM
WATCH IN EFFECT UNTIL 8 PM PDT ACROSS ALL OF THE OREGON ZONES AND
PARTS OF WASHINGTON. IT MAY NOT BE THE STRONGEST JET...BUT IN THE
UPPER LEVELS A WEAK 250MB/JET RIGHT REAR QUADRANT TRIES TO DEVELOP
OVER THE EASTERN FORECAST AREA LATE THIS AFTERNOON/EVENING...WHICH
MAY ADD TO THE CONVECTIVE DEVELOPMENT WHERE STRONG STORMS ARE
POSSIBLE ALONG WITH GOOD UPPER LEVEL DIFFLUENCE.

IMPRESSIVE 7/5H LAPSE RATES WERE ACROSS THE REGION AND WOULD EXPECT
CONVECTIVE DEVELOPMENT THAT BEGAN OVER THE SOUTHERN FORECAST AREA
THIS AFTERNOON TO MIGRATE NORTH THIS EVENING. WHETHER IT CAN MAKE IT
INTO THE BASIN WILL BE THE CHALLENGE. RIGHT NOW THE FORECAST
SOUNDINGS WERE SHOWING A STRONG CAP TO BE IN PLACE HOWEVER...IF
BOUNDARIES DEVELOPMENT THEN THIS SHUD BREAK AND WILL LEAVE IN ISOLD
TSRA FOR THIS EVENING. 5H/LOW PRESSURE OVER SE OR IS RESPONSIBLE FOR
THE CONVECTIVE DEVELOPMENT. THIS LOW IS EXPECTED TO TRACK ENE AND
WEAKEN BECOMING A LONG WAVE TROUGH ACROSS THE REGION TONIGHT. WOULD
EXPECT SHRA/TSRA TO PERSIST ACROSS PORTIONS OF THE AREA TONIGHT.

SLOW MOVING 5H/VORT MAX OVER THE EASTERN FORECAST AREA ALONG WITH
7H/MOISTURE REMAINING OVER OVER THE BLUES/WALLOWAS TOMORROW SHUD
HELP KEEP SHOWERS/TSRA HERE. IN ADDITION...ANOTHER WEAK DISTURBANCE
ENTERS THE PACNW WHICH MAY PRODUCE ISOLD TSRA OVER THE CASCADES AS
WELL.

STRONG LOW PRESSURE OVER THE EPAC WILL APPROACH THE REGION
WEDNESDAY. THIS MAY INCREASE PRECIPITATION CHANCES TO THE AREA
PRIMARILY OVER THE AREA MOUNTAINS. AFTERNOON HIGH TEMPERATURES
SHOULD BE SEVERAL DEGREES WARMER AS WELL.

.LONG TERM...THURSDAY THROUGH MONDAY...A RELATIVELY DEEP UPPER LOW
WILL SET UP OFF THE CENTRAL BRITISH COLUMBIA COAST NEAR THE END OF
THE WEEK. THE TRAILING COLD FRONT WILL MOVE THROUGH OUR AREA
WEDNESDAY NIGHT AND THURSDAY...BRINGING COOLER TEMPERATURES AND
UNSETTLED WEATHER. IT APPEARS THAT THERE WILL BE GOOD DYNAMICS WITH
THE COLD FRONT...BUT THE AMOUNT OF MOISTURE REMAINS UNCERTAIN.
THUS...WILL CONTINUE WITH 20-30 POPS WEDNESDAY NIGHT AND THURSDAY.
MODELS THEN SHOW A GRADUAL WARMING AND DRYING TREND THROUGH THE
WEEKEND AS HIGH PRESSURE BUILDS INTO THE PACIFIC NORTHWEST.

&&

.PRELIMINARY POINT TEMPS/POPS...
PENDLETON (AIRPORT) 061 088 060 091 / 030 010 010 010
WALLA WALLA         065 088 064 091 / 030 010 010 010
TRI-CITIES          062 090 061 093 / 020 010 010 010
YAKIMA              059 088 058 091 / 020 010 010 010
HERMISTON           061 089 060 092 / 020 010 010 010
ELLENSBURG          060 084 059 087 / 020 010 010 010
REDMOND             049 085 047 088 / 030 010 010 010
LA GRANDE           053 085 052 089 / 040 020 020 010
JOHN DAY            053 088 052 091 / 040 020 020 010
THE DALLES          065 085 063 089 / 020 010 010 010
&&

.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.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
233 PM PDT MON AUG 02 2004

..TIME...   ...EVENT...     ...CITY LOCATION...      ...LAT.LON...
..DATE...   ....MAG....     ..COUNTY LOCATION...ST.. ...SOURCE....
            ..REMARKS..

1250 PM     HAIL             N AUSTIN                44.60N 118.49W
08/02/2004  0.75 INCH        GRANT              OR   TRAINED SPOTTER

            PENNY SIZE HAIL. WIND BROUGHT DOWN LIMBS 1-2 INCHES IN
            DIAMETER. HAIL COVERED GROUND.

0155 PM     HAIL             2 S BEND                44.04N 121.31W
08/02/2004  0.75 INCH        DESCHUTES          OR   TRAINED SPOTTER

            PENNY SIZE HAIL, AND WATER RUNNING DOWN HILL INTO
            SPOTTERS SHOP.

&&

JCM