Severe Thunderstorm Warning 9, NWS Pendleton, OR

NORTHEAST OREGON/SOUTHEAST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
245 PM PDT SAT MAY 24 2003

A FAIRLY DEEP TROUGH IS OFF THE WEST COAST AND BECOMING NEGATIVELY
TILTED WITH TIME. THE MAIN LOW IS EXPECTED TO MOVE INTO BRITISH
COLUMBIA...HOWEVER A SERIES OF WEAK SHORT WAVES WILL AFFECT THE
WEATHER ACROSS THE CWFA THE NEXT 36 HOURS. THE ASSOCIATED COLD FRONT
WILL WEAKEN AND MOVE ACROSS THE REGION OVERNIGHT AND BE EAST OF THE
CWFA BY SUNDAY MORNING. HOWEVER THIS WILL BE THE FOCUSING POINT FOR
CONVECTION THE REMAINDER OF THE AFTERNOON AND OVERNIGHT. HIGH
INSTABILITY PARAMETERS IN CONJUNCTION WITH MID 50S PLUS DEWPOINTS
AND A SURFACE BOUNDARY WILL RESULT IN AREAS OF DEEP CONVECTION.
CURRENTLY SPC HAS A LARGE PORTION OF EASTERN OREGON/WASHINGTON IN A
SEVERE THUNDERSTORM WATCH THROUGH 1900 LOCAL TIME TONIGHT. THE
ATMOSPHERE WILL BEGIN TO STABILIZE BEHIND THE COLD FRONT...BUT
SHOWERS AND THUNDERSTORMS ARE EXPECT TO LINGER THROUGH EARLY SUNDAY
ACROSS THE SOUTHEAST PORTIONS OF THE ZONE. EXPECT A 8-12 DEGREE COOL
DOWN ON SUNDAY FOLLOWED BY A COUPLE DEGREE WARMING ON MONDAY. BREEZY
WINDS CAN ALSO BE EXPECTED IN THE USUAL LOCATIONS WITH AND BEHIND
THE FRONTAL PASSAGE. TOBIN

DAYS 3-7...A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE WESTERN
U.S...CENTERED OVER THE GREAT PLAINS REGION ON TUESDAY.  THE RIDGE
WILL SLOWLY SHIFT EAST THROUGH THE PERIOD AS AN UPPER LEVEL TROUGH
REMAINS OFF COAST.  A SERIES OF DISTURBANCES WILL BE KICKED OUT OF
THE TROUGH...MOST WILL TRACK WELL TO OUR NORTH THROUGH ONE MAY BRUSH
ACROSS OUR WASHINGTON CASCADES ON WEDNESDAY.  THIS WEATHER PATTERN
WILL PROVIDE GENERALLY DRY AND WARM CONDITIONS THROUGH THE EXTENDED
PERIOD.  MJB.

PDT 3200  ALW 3200  PSC 2100  YKM 2100

.KPDT...NONE.

ORZ041>050-WAZ024>030-251300-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE PENDLETON OR
500 AM PDT SAT MAY 24 2003

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

.DAY ONE... SATURDAY

SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND
THIS EVENING OVER THE MOUNTAINS OF NORTHEAST OREGON. THE SHOWERS AND
THUNDERSTORMS WILL MOVE NORTHEAST INTO SOUTHEAST WASHINGTON THIS
EVENING. A COLD FRONT WILL SWEEP ACROSS THE REGION LATE THIS
AFTERNOON AND THIS EVENING. A VERY MOIST AND UNSTABLE AIR MASS HAS
MOVED INTO THE REGION AHEAD OF THE FRONT AND THIS WILL SET THE STAGE
FOR THE DEVELOPMENT OF STRONG THUNDERSTORMS...WHICH WILL HAVE THE
POTENTIAL FOR PRODUCING LARGE HAIL AND DAMAGING WINDS THIS AFTERNOON
AND THIS EVENING.

.DAYS TWO THROUGH SEVEN... SUNDAY THROUGH FRIDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL BE LIKELY THIS AFTERNOON AND THIS EVENING TO
DEAL WITH POSSIBLE SEVERE WEATHER ASSOCIATED WITH THUNDERSTORMS.

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