Flash Flood Warning 16, NWS Pendleton, OR

AREA FORECAST DISCUSSION...CORRECTED...
NATIONAL WEATHER SERVICE PENDLETON OREGON
905 PM PDT THU AUG 19 2004

.SHORT TERM...TONIGHT THROUGH SUNDAY...A MID LEVEL LOW PRESSURE
SYSTEM IS MOVING EAST ACROSS CENTRAL OREGON AND IS ACCOMPANIED BY
RELATIVELY HIGH MOISTURE. UPON MOVING EAST OF THE OREGON CASCADES
INTO JEFFERSON COUNTY...THIS SYSTEM GENERATED STRONG UPPER LEVEL
DIRECTIONAL SHEAR...WHICH IN TURN CREATED STRONG UPPER LEVEL
DIVERGENCE WHICH THEN TRIGGERED A SEVERE THUNDERSTORM IN DESCHUTES
COUNTY BEGINNING AROUND 720 PM THIS EVENING. THE STORM PRODUCED
LARGE HAIL UP TO ONE INCH IN DIAMETER AND 0.75 INCHES OF RAIN IN 45
MINUTES JUST SOUTHWEST...SOUTH AND SOUTHEAST OF BEND. AS THIS
DISTURBANCE MOVES EAST THROUGH CENTRAL OREGON THE POTENTIAL EXISTS
THROUGH THE REMAINDER OF THIS EVENING FOR ADDITIONAL ISOLATED
STRONG THUNDERSTORMS IN CROOK...WHEELER AND GRANT COUNTIES. LOCALLY
HEAVY RAIN IS POSSIBLE WITH THESE THUNDERSTORMS...WHICH COULD CAUSE
FLASH FLOODING AND MUD OR ROCK SLIDES IN STEEP TERRAIN. AS SUCH...A
FLASH FLOOD WATCH WILL BE CONTINUED IN CROOK...WHEELER AND GRANT
COUNTIES UNTIL MIDNIGHT.

ISOLATED THUNDERSTORMS WILL BE POSSIBLE FRIDAY IN THE ALDRICH AND
STRAWBERRY MOUNTAINS IN SOUTHERN GRANT COUNTY AND IN THE MOUNTAINS
OF SOUTHEASTERN CROOK COUNTY...THE EXTREME SOUTHERN BLUE
MOUNTAINS...THE GRANDE RONDE VALLEY AND OVER THE WALLOWA MOUNTAINS.

ON SATURDAY THE UPPER LEVEL HIGH PRESSURE RIDGE WILL BREAK DOWN AND
ALLOW A COLD FRONT TO MOVE INTO THE REGION LATE SATURDAY NIGHT FOR A
CHANCE OF SHOWERS AND THUNDERSTORMS AND COOLER TEMPERATURES SUNDAY.
POLAN

&&

.PRELIMINARY POINT TEMPS/POPS...
PENDLETON (AIRPORT) 066 092 064 090 / 005 000 000 005
WALLA WALLA         068 095 065 091 / 010 000 000 005
TRI-CITIES          063 097 062 093 / 005 000 000 005
YAKIMA              060 095 059 090 / 020 000 000 005
HERMISTON           064 096 062 092 / 005 000 000 005
ELLENSBURG          061 091 059 088 / 020 000 005 010
REDMOND             054 091 050 087 / 020 000 005 005
LA GRANDE           056 091 054 090 / 030 020 000 010
JOHN DAY            058 094 057 091 / 030 010 005 010
THE DALLES          065 093 064 089 / 005 000 005 010
&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FLASH FLOOD WATCH CONTINUES UNTIL MIDNIGHT FOR CROOK...WHEELER
     AND GRANT COUNTIES.
WA...NONE.
&&

99

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE PENDLETON OREGON
940 AM PDT THU AUG 19 2004

CORRECTED TO MENTION FLOOD WATCH FOR FLASH FLOODING IN TEXT WORDING

ORZ041>050-WAZ024>030-201200-
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-
940 AM PDT THU AUG 19 2004

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

.DAY ONE...TODAY AND TONIGHT

FLOODING
     CENTRAL OREGON, BLUE MOUNTAINS, JOHN DAY BASIN, OCHOCO-JOHN DAY
     HIGHLANDS, GRANDE RONDE VALLEY, WALLOWA COUNTY

THUNDERSTORMS
     EAST SLOPES OF THE SOUTHERN CASCADES, CENTRAL OREGON, BLUE
     MOUNTAINS (WA)

LOW PRESSURE WILL MOVE INTO THE PACIFIC NORTHWEST AND COMBINE WITH
LOW LEVEL MOISTURE TO PRODUCE ISOLATED THUNDERSTORMS ACROSS PORTIONS
OF THE AREA. SLOW MOVING THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS
AFTERNOON AND EVENING...WHICH WILL LIKELY RESULT IN FLASH FLOODING
NEAR THUNDERSTORMS. A FLOOD WATCH FOR FLASH FLOODING IS IN EFFECT
FOR THIS AFTERNOON AND EVENING FOR PORTIONS OF THE AREA.  PLEASE SEE
PRODUCT PDXFFAPDT FOR DETAILS. SOME OF THE STORMS MAY BECOME STRONG
PRIMARILY EAST OF A LINE FROM SISTERS OREGON TO PILOT ROCK TO DAYTON
WASHINGTON. ALSO THE EAST SLOPES OF THE WASHINGTON CASCADES MAY
RECEIVE ISOLATED STRONG THUNDERSTORMS. THE STRONG STORMS MAY CONTAIN
HAIL...HEAVY RAIN...AND FREQUENT LIGHTNING. ALTHOUGH BRIEF GUSTY
WINDS TO 45 MPH ARE POSSIBLE.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORMS FRIDAY
          JOHN DAY BASIN, OCHOCO-JOHN DAY HIGHLANDS, GRANDE RONDE
          VALLEY, WALLOWA COUNTY

THUNDERSTORMS SUNDAY
          EAST SLOPES OF THE SOUTHERN CASCADES, JOHN DAY BASIN,
          OCHOCO-JOHN DAY HIGHLANDS

FOR FRIDAY MOISTURE WILL LINGER ACROSS PORTIONS OF THE AREA AND WILL
COMBINE WITH DAYTIME HEATING TO PRODUCE ISOLATED THUNDERSTORMS
MAINLY OVER THE JOHN DAY BASIN...BLUE AND WALLOWA MOUNTAINS.

BY SUNDAY A COLD FRONT WILL MOVE ACROSS THE AREA. THIS WILL HELP TO
PRODUCE SCATTERED THUNDERSTORMS OVER THE EAST SLOPES OF THE
WASHINGTON CASCADES AND THE JOHN DAY BASIN.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS LIKELY THIS AFTERNOON AND EVENING FOR FLASH
FLOODING.

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.