Severe Thunderstorm Warning 23, NWS Pendleton, OR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OREGON
250 PM PDT MON JUL 19 2004

.SHORT TERM...A VIGOROUS SHORT WAVE IS MOVING NORTH INTO CENTRAL
AND NORTHEAST OREGON AND IS TAPPING INTO MID LEVEL MOISTURE AND
INSTABILITY THIS AFTERNOON. THIS HAS TRIGGERED STRONG TO SEVERE
THUNDERSTORMS IN CENTRAL AND NORTHEAST OREGON THIS AFTERNOON. THESE
STORMS HAVE PRODUCED WINDS UP TO 90 MPH AND HAIL UP TO 1.75 INCHES
IN DIAMETER. THE SHORT WAVE WILL CONTINUE MOVING ACROSS CENTRAL AND
NORTHEAST OREGON AND THEN INTO SOUTHEAST WASHINGTON TRIGGERING MORE
SHOWERS AND THUNDERSTORMS...SOME OF THEM POSSIBLY STRONG OR
SEVERE...THROUGH THE REST OF THIS AFTERNOON AND INTO THIS EVENING.
SHOWERS AND THUNDERSTORMS SHOULD TAPER OFF AFTER MIDNIGHT.

A STRONGER SHORT WAVE WILL MOVE ACROSS THE REGION LATER TONIGHT AND
TUESDAY MORNING. THIS WAVE WILL KEEP A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS IN THE BLUE MOUNTAINS LATE TONIGHT AND INTO TUESDAY
MORNING. ON TUESDAY THE FLOW ALOFT WILL BECOME WESTERLY AND THE AIR
MASS WILL BE DRIER AND MORE STABLE OVER MOST OF THE FORECAST AREA.
THUS TUESDAY WILL BE DRY IN MOST AREAS...EXCEPT FOR A SLIGHT CHANCE
OF SHOWERS AND THUNDERSTORM IN WALLOWA COUNTY. THE FLOW ALOFT WILL
REMAIN WESTERLY TUESDAY NIGHT AND WEDNESDAY WITH SLIGHTLY COOLER
MARINE AIR MOVING INLAND FROM THE NORTHEAST PACIFIC FOR DRY AND
STABLE CONDITIONS EAST OF THE CASCADES TUESDAY NIGHT AND WEDNESDAY.
POLAN

.LONG TERM...THURSDAY NIGHT THROUGH MONDAY...THE UPPER LEVEL RIDGE
WILL BUILD OFFSHORE...THEN MOVE SLOWLY INLAND OVER EASTERN
WASHINGTON AND OREGON FRIDAY AND SATURDAY. TEMPERATURES WILL
INCREASE THURSDAY THROUGH SATURDAY DUE TO SUBSIDENCE ASSOCIATED WITH
THE RIDGE. THE SUBSIDENCE WILL ALSO KEEP THE AREA SUNNY AND DRY WITH
RH VALUES DROPPING INTO SINGLE DIGITS NEXT WEEKEND. BY MONDAY THE
RIDGE AXIS WILL MOVE EAST INTO MONTANA. THE ECMWF MODEL SHOWS THE
UPPER LEVEL FLOW SOUTHWEST...KEEPING THE ATMOSPHERE TOO DRY FOR
THUNDERSTORM DEVELOPMENT. THE GFS BRINGS IN A MORE MOIST SOUTHERLY
FLOW. AT THIS TIME OPTED TO KEEP THE FORECAST DRY DUE TO MODEL
DIFFERENCES SINCE EVEN THE GFS SHOWS LIMITED MOISTURE AVAILABLE FROM
THE OCHOCOS TO THE WALLOWAS. COONFIELD

&&

.PRELIMINARY POINT TEMPS/POPS...
PENDLETON (AIRPORT) 061 085 058 084 / 040 005 000 000
WALLA WALLA         062 087 060 085 / 040 005 000 000
TRI-CITIES          061 088 056 086 / 030 005 000 000
YAKIMA              057 084 055 084 / 020 005 000 000
HERMISTON           061 086 056 086 / 030 005 000 000
ELLENSBURG          057 078 055 083 / 020 010 000 000
REDMOND             048 084 045 084 / 040 010 000 000
LA GRANDE           054 083 053 083 / 060 010 000 000
JOHN DAY            055 083 052 083 / 040 010 000 000
THE DALLES          064 083 060 083 / 020 005 000 000
&&

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

99

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OREGON
512 AM PDT MON JUL 19 2004

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-
512 AM PDT MON JUL 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

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, 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

WIDESPREAD INSTABILITY...ABUNDANT LOW TO MID LEVEL MOISTURE AND A
WEATHER DISTURBANCE WILL CAUSE ISOLATED TO SCATTERED THUNDERSTORMS
TODAY...MAINLY OVER THE EASTERN MOUNTAINS AND ALONG THE CASCADES
CREST AND EAST SLOPES.  THESE STORMS WILL PRODUCE FREQUENT
LIGHTNING...BRIEF HEAVY RAIN AND POSSIBLE GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

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

LINGERING MOISTURE AND INSTABILITY WILL ALLOW FOR ISOLATED
THUNDERSTORMS IN THE NORTHEAST OREGON AND SOUTHEAST WASHINGTON
MOUNTAINS ON TUESDAY.  AFTER TUESDAY DRY AND STABLE AIR WILL MOVE
INTO THE REGION WITH BUILDING HIGH PRESSURE AND WARMING TEMPERATURES
AGAIN.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED.

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
238 PM PDT MON JUL 19 2004

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

1235 PM     HAIL             6 SSW PRAIRIE CITY      44.84N 119.41W
07/19/2004  0.75 INCH        GRANT              OR   TRAINED SPOTTER

            PENNY SIZED HAIL AND HEAVY RAIN REPORTED.

0120 PM     HAIL             13 NNE POST             44.32N 120.38W
07/19/2004  1.75 INCH        CROOK              OR   OTHER FEDERAL

            UP TO GOLF BALL SIZED HAIL AT LOOKOUT
            MOUNTAIN...ELEVATION 6900 FT.

0135 PM     TSTM WND GST     1 N WINLOCK             44.91N 119.89W
07/19/2004  40 MPH           WHEELER            OR   TRAINED SPOTTER

            SMALL HAIL AND HEAVY RAIN...WIND GUST TO APPROXIMATELY 40
            MPH REPORTED.

0145 PM     TSTM WND GST     2 E MITCHELL            44.57N 120.15W
07/19/2004  90 MPH           WHEELER            OR   CO-OP OBSERVER

            ESTIMATED 80-90 MPH WIND GUSTS...TREE LIMBS DOWN...1/8
            INCH HAIL...HEAVY RAIN.

0152 PM     TSTM WND DMG     1 N MITCHELL            44.91N 119.89W
07/19/2004                   WHEELER            OR   TRAINED SPOTTER

            TREE LIMBS DOWN DUE TO STRONG WIND GUSTS.

0215 PM     HAIL             1 ENE NORTH POWDER      45.04N 117.90W
07/19/2004  0.88 INCH        UNION              OR   TRAINED SPOTTER

            NICKEL SIZED HAIL...HEAVY RAIN...STRONG WINDS BROUGHT
            TREE LIMBS DOWN.

0230 PM     HAIL             N KIMBERLY              44.76N 119.64W
07/19/2004  0.50 INCH        GRANT              OR   TRAINED SPOTTER

            MARBLE SIZED HAIL.

&&

ADAMS