Severe Thunderstorm Warning 16, NWS Pendleton, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OREGON
200 PM PDT WED JUN 30 2004

CORRECTED COUNTY LIST FOR WATCH

.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT...LATEST WATER VAPOR
IMAGERY SHOWS BROAD LOW PRESSURE ACROSS THE NORTHEAST PACIFIC...WITH
SEVERAL WAVES MIGRATING NORTHWARD ACROSS THE PACIFIC NORTHWEST...ONE
RATHER WEAK WAVE IS MOVING NORTH ACROSS WESTERN WA...PRODUCING ISO
TO SCT SHWRS ALONG THE CASCADE EAST SLOPES...WITH A STRONGER IMPULSE
MOVING NORTH INTO SOUTHERN OR. WITH LESS CLOUDS THIS MORNING
ACROSS OREGON...TOWERING CUMULUS IS FORMING ACROSS MUCH OF THE
AREA...WITH CONVECTION POPPING UP AS FAR NORTH AS SOUTH-CENTRAL OR...
WITH A SHWR ACROSS SOUTHERN WHEELER COUNTY. EXPECT THIS TREND TO
CONTINUE AS FURTHER HEATING/DESTABILIZATION TAKES PLACE ACROSS
CENTRAL...AND EVENTUALLY NORTHERN OR.

TNGT...THE WAVE TO THE SOUTH WILL APPROACH CENTRAL/NE OR THIS
EVENING...EXIT TO THE NE BY 12Z. AMPLE MID-LEVEL MOISTURE WITH
PRECIPITABLE WATERS REMAINING AROUND 1.00 INCH (150-200% OF
NORMAL)...INSTABILITY...AND FAVORABLE UPPER LEVEL DIVERGENCE
REMAIN IN PLACE...AND WITH THE LIFT FROM THE WAVE...SHWRS/TSTMS
WILL INCREASE LATER THIS AFTERNOON...MAXIMIZING THIS EVENING.
STEERING WINDS IN THE LOWER AND MIDDLE LEVELS OF THE ATMOSPHERE
ARE A LITTLE STRONGER THAN TUESDAY...BUT NOT VERY MUCH...AND WITH
THE RICH MOISTURE...STILL THINK SOME STORMS COULD PRODUCE FLOODING.
THUS...WILL CONTINUE THE FLOOD WATCH UNTIL 11 PM. COULD ALSO SEE
SOME POTENT WIND GUSTS WITH SOME DRIER AIR AT 5000-10000FT...AND
SOME HAIL WITH SLIGHTLY LOWER FREEZING HEIGHTS THAN TUESDAY. WILL
HIT THE HEAVY RAIN HARDEST...BUT MENTION WIND/HAIL AS WELL. TSTM
COVERAGE WILL DECREASE AFT MIDNIGHT WITH LOSS OF HEATING AND WAVE
MOVING OFF TO THE NE.

THU/THU NIGHT...A TROUGH OF LOW PRESSURE NUDGING SLOWLY EAST ACROSS
THE PACIFIC WILL TURN WINDS MORE SW VERSUS WEST...RESULTING IN A
SLIGHTLY DRIER ATMOSPHERE...AND INCREASING STEERING WINDS. COULD
STILL SEE SOME LOCALIZED HEAVY RAIN ACROSS THE EASTERN MTNS AS WINDS
WILL TURN SW LATER THERE...BUT WILL TREND POPS DOWNWARD...WITH LOW
END CHC EASTERN MTNS...WITH SCHC POPS AS FAR WEST AS THE DESCHUTES
PLATEAU/BLUE MTN FOOTHILLS.

FRI/FRI NIGHT...LOW PRESSURE WILL MOVE ONSHORE SE ALASKA...WITH W/SW
FLOW INCREASING ACROSS THE REGION. CONTINUED DRYING WILL TAKE PLACE
ACROSS MOST OF THE AREA...WITH SCHC/PERHAPS LOW END CHC POPS FOR
THE EASTERN MTNS FRI AFTN/EVE WITH RESIDUAL INSTABILITY.

.LONG TERM...SATURDAY THROUGH WEDNESDAY...UNSETTLED WEATHER WILL
CONTINUE THROUGH THE HOLIDAY WEEKEND AS A TROUGH OF LOW PRESSURE
PUSHES THROUGH THE PACIFIC NORTHWEST.  GFS MODEL FINALLY COMING INTO
AGREEMENT WITH FASTER EURO AND CANADIAN SOLUTIONS WITH MOVING THE
SYSTEM THROUGH EASTERN WASHINGTON INTO NORTHERN IDAHO AND OUT OF THE
PACIFIC NORTHWEST BY MONDAY.  THIS SYSTEM WILL BRING WITH IT ENOUGH
ENERGY AND JET DYNAMICS TO FIRE UP SHOWERS AND THUNDERSTORMS DURING
THE AFTERNOONS SATURDAY/SUNDAY OVER THE CENTRAL AND EASTERN
MOUNTAINS AS WELL AS THE SOUTHERN WASHINGTON CASCADES.  A MARINE
PUSH WILL ALSO ACCOMPANY THIS SYSTEM WITH WINDS PICKING UP ACROSS
THE COLUMBIA RIVER BASIN...COLUMBIA RIVER GORGE...AND THE KITTITAS
VALLEY LATE SATURDAY THROUGH SUNDAY.  AFTER THE SYSTEM PULLS TO THE
EAST MONDAY MODELS SHOW GENERAL AGREEMENT THAT A RIDGE OF HIGH
PRESSURE WILL BUILD OVER WASHINGTON/OREGON FOR DRY AND WARM
CONDITIONS.

&&

.PRELIMINARY POINT TEMPS/POPS...
PENDLETON (AIRPORT) 62 91 60 89 / 30 20 20 10
WALLA WALLA         65 91 61 89 / 30 20 20 10
TRI-CITIES          62 93 58 91 / 30 10 10 10
YAKIMA              56 92 56 90 / 30 05 05 10
&&

.PDT WATCHES/WARNINGS/ADVISORIES...
OR...FLOOD WATCH FOR FLASH FLOODING UNTIL 11 PM TONIGHT FOR
DESCHUTES...JEFFERSON...CROOK...WHEELER...GRANT...UNION...
WALLOWA...UMATILLA...AND MORROW COUNTIES.
WA...NONE.
&&

89/CANTIN

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OREGON
1210 PM PDT WED JUN 30 2004

ORZ041>050-WAZ024>030-011200-
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-
1210 PM PDT WED JUN 30 2004

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

.DAY ONE...

FLOODING
     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

THUNDERSTORMS
     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

SHOWERS AND THUNDERSTORMS WILL REDEVELOP THIS AFTERNOON AND EVENING
OVER THE MOUNTAINS OF CENTRAL AND EASTERN OREGON AND SOUTHEAST
WASHINGTON. THE MAIN THREAT FROM THUNDERSTORMS WILL BE HEAVY
DOWNPOURS. LOCAL FLASH FLOODING IS POSSIBLE...THUS A FLOOD WATCH FOR
FLASH FLOODING HAS BEEN ISSUED FOR MOST OF CENTRAL AND NORTHEAST
OREGON SEE THE LATEST PDXFFAPDT OR WGUS46 KPDT FOR THE DETAILS. A
FEW THUNDERSTORMS MAY ALSO PRODUCE HAIL UP TO 3/4 OF AN INCH.
SHOWERS AND THUNDERSTORMS WILL TAPER OFF AFTER MIDNIGHT.

.DAYS TWO THROUGH SEVEN...

THUNDERSTORMS THURSDAY
          NORTHWEST BLUE MOUNTAINS, NORTH CENTRAL OREGON, CENTRAL
          OREGON, BLUE MOUNTAINS, JOHN DAY BASIN, OCHOCO-JOHN DAY
          HIGHLANDS, GRANDE RONDE VALLEY, WALLOWA COUNTY

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

THUNDERSTORMS SATURDAY
          FOOTHILLS OF THE BLUE MOUNTAINS (WA), NORTHWEST BLUE
          MOUNTAINS, NORTH CENTRAL OREGON, CENTRAL OREGON, FOOTHILLS
          OF THE BLUE MOUNTAINS (OR), BLUE MOUNTAINS, JOHN DAY BASIN,
          OCHOCO-JOHN DAY HIGHLANDS, GRANDE RONDE VALLEY, WALLOWA
          COUNTY

THUNDERSTORMS SUNDAY
          FOOTHILLS OF THE BLUE MOUNTAINS (WA), NORTHWEST BLUE
          MOUNTAINS, FOOTHILLS OF THE BLUE MOUNTAINS (OR), BLUE
          MOUNTAINS, JOHN DAY BASIN, OCHOCO-JOHN DAY HIGHLANDS,
          GRANDE RONDE VALLEY, WALLOWA COUNTY

THUNDERSTORMS MONDAY
          NORTHWEST BLUE MOUNTAINS, BLUE MOUNTAINS, JOHN DAY BASIN,
          OCHOCO-JOHN DAY HIGHLANDS, GRANDE RONDE VALLEY, WALLOWA
          COUNTY

UNSETTLED WEATHER WILL CONTINUE THROUGH THE HOLIDAY WEEKEND WITH
SHOWERS AND THUNDERSTORMS POSSIBLE OVER THE CENTRAL AND EASTERN
MOUNTAINS OF OREGON AS A LOW PRESSURE SYSTEM PUSHES TO THE NORTH
OVER WASHINGTON.  BY THE MIDDLE OF NEXT WEEK A RIDGE OF HIGH
PRESSURE WILL BUILD BACK OVER THE REGION FOR WARMER AND CALMER
WEATHER.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED.

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