Severe Thunderstorm Warning 37, NWS Pendleton, OR

NORTHEAST OREGON/SOUTHEAST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
230 PM PDT WED JUL 24 2002

FIRE WEATHER...THE ATMOSPHERE WILL BE MOIST ENOUGH FOR SOME RAIN
FROM THUNDERSTORMS THIS AFTERNOON...TONIGHT AND THURSDAY...BUT
THERE IS STILL A FIRE WEATHER CONCERN AS MOST OF THE RAIN WILL BE
LIGHT AND SPOTTY.  POLAN

SHORT TERM...AN UNSTABLE ATMOSPHERE AND SUFFICIENT MID LEVEL
MOISTURE ARE IN PLACE ACROSS EASTERN OREGON AND SOUTHEAST
WASHINGTON. A SHORT WAVE WILL MOVE ACROSS EASTERN OREGON AND
SOUTHEAST WASHINGTON TONIGHT ALONG WITH A JET STREAK AROUND 30000
FEET CONTAINING 60-70 KNOT WINDS. THIS ENERGY WILL PROVIDE DYNAMIC
LIFT WHICH WILL TAP INTO THE INSTABILITY THUS PRODUCING SCATTERED
THUNDERSTORMS THIS AFTERNOON AND TONIGHT. MID LEVEL WIND SHEAR WILL
HELP SOME OF THE THUNDERSTORMS TO BECOME ORGANIZED WITH THE
POTENTIAL TO PRODUCE STRONG GUSTY WINDS AND LARGE HAIL.

THE UPPER LEVEL TROUGH WILL MOVE THROUGH THE REGION ON THURSDAY AND
WILL INTERACT WITH UNSTABLE AIR FOR ANOTHER ROUND OF THUNDERSTORMS.
THE AFOREMENTIONED UPPER TROUGH WILL SHIFT EAST OF THE FORECAST AREA
ON THURSDAY NIGHT AND THIS WILL ALLOW COOLER MARINE AIR IN THE
SURFACE LAYERS AND DRIER AND COOLER AIR ALOFT TO PUSH INTO SOUTHERN
WASHINGTON AND OREGON ON FRIDAY. POLAN

EXTENDED...ANOTHER STRONGER SHORT WAVE THAT WILL BE DIGGING DOWN
INTO THE PACIFIC NORTHWEST ON FRIDAY WILL BE IN IDAHO BY SATURDAY.
THICKNESSES WILL CONTINUE TO FALL INTO SATURDAY WITH THE PASSAGE OF
THIS SYSTEM...HELPING TO LOWER THE TEMPERATURES ACROSS EASTERN
OREGON AND WASHINGTON. MEANWHILE...THE MOISTURE ASSOCIATED WITH THIS
SYSTEM WILL PASS BY TO OUR NORTH AND EAST. ON SUNDAY...A RIDGE
BEGINS TO BUILD INTO THE PACIFIC NORTHWEST...BRINGING A DRY AND
STABLE ATMOSPHERE TO THE REGION. THIS WILL ALLOW TEMPERATURES TO
BEGIN TO SLOWLY RISE. ON MONDAY...A WEAK WAVE PASSES THROUGH THE
UPPER LEVEL RIDGE...FLATTENING THE RIDGE. HOWEVER...OREGON AND
SOUTHERN WASHINGTON WILL REMAIN DRY...WITH THE HIGH TEMPERATURES
CONTINUING TO RISE. DRY AND WARMING CONDITIONS CONTINUE ON
TUESDAY...AS THE RIDGE BECOMES WELL ESTABLISHED OVER THE PACIFIC
NORTHWEST. A TROUGH ALSO BEGINS TO DIG SOUTH INTO THE PACIFIC ON
TUESDAY...WHICH WILL HELP HURRICANE ELIDA RECURVE OVER COOLER SEA
SURFACE TEMPERATURE IN THE NORTHEAST PACIFIC. BY WEDNESDAY...THE
UPPER LEVEL TROUGH IS MOVING TOWARDS THE WEST COAST...TURNING THE
UPPER LEVEL FLOW TO THE SOUTHWEST. THE REMNANT LOW OF HURRICANE
ELIDA WILL BE CAUGHT UP IN THE UPPER LEVEL PATTERN WITH THE TROUGH
PUSH TOWARDS THE COAST. THIS PROVIDES A TROPICAL MOISTURE SOURCE
THAT BEGINS TO INFILTRATE SOUTHERN AND EASTERN OREGON ON
WEDNESDAY...THAT WILL PRODUCE THUNDERSTORMS EXTENDING NORTHEAST FROM
REDMOND TO THE BLUE AND WALLOWA MOUNTAINS WHILE THE REST OF THE CWA
WILL REMAIN DRY AND HOT.  PALMER

PDT 3200  ALW 3300  PSC 3200   YKM 2200

KPDT...VCP21/PRECIP...OPERATIONAL.

.KPDT...FIRE WEATHER WATCH FOR DRY LIGHTNING FOR TONIGHT FOR THE
        LOWER COLUMBIA BASIN AND THE FOOTHILLS OF THE BLUE MOUNTAINS
        IN THE FOLLOWING COUNTIES:
        WASHINGTON: KLICKITAT...BENTON...FRANKLIN...WALLA WALLA AND
                    COLUMBIA.
        OREGON: GILLIAM...MORROW AND UMATILLA.