Tornado in Oregon, May 23, 2004

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OREGON
235 PM PDT SUN MAY 23 2004

.SHORT TERM...AN UPPER-LEVEL LOW PRESSURE SYSTEM IS TRACKING SLOWLY
EASTWARD ACROSS CENTRAL IDAHO AND WESTERN MONTANA.  RESIDUAL
WRAP-AROUND SHOWERS ARE BEING GENERATED ALONG THE WESTERN SIDE OF
THE LOW ACROSS THE AREA.  WITH A NEAR SATURATED ATMOSPHERE IN PLACE
THE SHOWERS BEING CREATED ARE PRODUCING HEAVY RAIN WHICH HAS BEEN
FALLING ON TOP OF NEARLY SATURATED SOILS ALONG THE BLUE MOUNTAINS
AND BLUE MOUNTAIN FOOTHILLS.  REPORTS OF CREEK AND SMALL RIVER
FLOODING HAVE BEEN COMING IN THIS AFTERNOON ALONG THE FOOTHILLS OF
THE BLUE MOUNTAINS FROM HEPPNER EASTWARD TO PENDLETON.  SHOWERS AND
ISOLATED THUNDERSTORMS WILL CONTINUE THROUGH THIS EVENING.

THE UPPER-LEVEL LOW WILL SLIDE INTO CENTRAL MONTANA BY MONDAY
AFTERNOON...HOWEVER LINGERING MOISTURE ALONG WITH COOL AIR ALOFT
WILL HELP TO GENERATE SHOWERS ESPECIALLY OVER THE HIGHER TERRAIN.
AREAS PRONE TO SHOWERS IN NORTHERLY FLOW WILL SEE THE MOST IMPACT
INCLUDING THE BLUE/WALLOWA MOUNTAINS AND THE EASTERN SLOPES OF THE
SOUTHERN WASHINGTON CASCADES.

BY EARLY TUESDAY A SHORT-LIVED RIDGE OF HIGH PRESSURE WILL MOVE OVER
THE AREA.  THIS WILL BRING PARTLY CLOUDY SKIES AND DRIER CONDITIONS
TO THE REGION.  CANTIN

.LONG TERM...FLOW LOOKS TO BECOME MORE ZONAL BY THE MIDDLE OF NEXT
WEEK. A STRONG WAVE IS EXPECTED TO MOVE INTO THE PACNW WEDNESDAY
NIGHT...THEN MOVE SLOWLY ACROSS THE REGION THURSDAY AND FRIDAY. FLAT
RIDGING SHOULD BE IN PLACE AGAIN BY NEXT WEEKEND. THUS MOST OF
EASTERN WASHINGTON AND OREGON SHOULD BE DRY...EXCEPT FOR A FEW
SHOWERS OVER THE WASHINGTON CASCADE EAST SLOPES AS WELL AS THE BLUE
AND WALLOWA MOUNTAINS. GKH

&&

.PRELIMINARY POINT TEMPS/POPS...
PENDLETON (AIRPORT) 43 68 44 73 / 30 20 20 05
WALLA WALLA         45 69 46 73 / 30 20 10 05
TRI-CITIES          44 73 44 79 / 20 20 10 05
YAKIMA              44 73 44 75 / 20 20 10 05
&&

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

96

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE PENDLETON OR
1145 AM PDT SUN MAY 23 2004

UPDATED TO MENTION URBAN/SMALL STREAM FLOOD WARNING IN DAY ONE

ORZ041>050-WAZ024>030-241200-
BLUE MOUNTAINS OF OREGON OR-CENTRAL OREGON OR-
EAST COLUMBIA RIVER GORGE OR-EAST COLUMBIA RIVER GORGE WA-
EAST SLOPES SOUTHERN CASCADES WA-FOOTHILLS OF THE BLUE MOUNTAINS WA-
FOOTHILLS OF THE BLUE MOUNTAINS OR-GRANDE RONDE VALLEY OR-
JOHN DAY VALLEY OR-KITTITAS VALLEY WA-LOWER COLUMBIA BASIN WA-
LOWER COLUMBIA BASIN OR-NORTH CENTRAL OREGON OR-
NORTHWEST BLUE MOUNTAINS WA-OCHOCO-JOHN DAY HIGHLANDS OR-
WALLOWA COUNTY OR-YAKIMA VALLEY WA-
1145 AM PDT SUN MAY 23 2004

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

.DAY ONE...TODAY AND TONIGHT

SCATTERED RAIN SHOWERS WILL CONTINUE TO MOVE THROUGH THE AREA. THESE
SHOWERS WILL ADD TO THE FLOOD POTENTIAL OF MANY CREEKS DESCENDING
FROM THE BLUE MOUNTAINS ALREADY SWOLLEN WITH RUN-OFF FROM THE
RAINFALL OF PREVIOUS DAYS.  AN URBAN/SMALL STREAM FLOOD WARNING HAS
BEEN ISSUED THROUGH 5 PM FOR MORROW AND UMATILLA COUNTIES IN
OREGON.  SEE THE LATEST PDXFLWPDT OR FGUS86 FOR THE DETAILS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

PRECIPITATION CHANCES WILL CONTINUE TO DECREASE EARLY IN THE
WEEK...AS LOW PRESSURE DEPARTS...AND A RIDGE OF HIGH PRESSURE
BUILDS IN BY TUESDAY. UNSETTLED WEATHER WILL RETURN LATE IN THE
WEEK AS LOW PRESSURE APPROACHES THE REGION.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED AT THIS TIME.

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