Severe Thunderstorm Warning 13, NWS Pendleton, OR

NORTHEAST OREGON/SOUTHEAST WASHINGTON FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PENDLETON OR
230 PM PDT THU JUN 23 1999

SEVERE THUNDERSTORM WATCH CONTINUES THROUGH 8 PM. MID-LEVEL COLD
POOL HAS DESTABILIZED THE ATMOSPHERE ACROSS NORTHEAST OREGON AND
SOUTHEAST WASHINGTON THIS AFTERNOON. WITH THE HELP OF A 90-KNOT
JET STREAK MOVING INTO THE REGION...SEVERE WEATHER THREAT WILL
REMAIN THROUGH THE EVENING.

MAIN UPPER TROUGH TO PASS TO THE EAST OF THE FORECAST AREA BY 06Z
EFFECTIVELY TAKING THE STRONGER DYNAMICS WITH IT. THIS WILL RESULT
IN SCATTERED EVENING SHOWERS AND THUNDERSTORMS BEFORE SKIES BECOME
PARTLY CLOUDY LATER. TIGHT SURFACE GRADIENT AND COLD AIR ADVECTION
WILL KEEP WINDS IN THE BREEZY CATEGORY TONIGHT.

GENERAL TROUGH CONDITIONS TO CONTINUE THROUGHOUT THE FORECAST
PERIOD ALTHOUGH ABUNDANT MOISTURE WILL BE LACKING. WILL THEREFORE
KEEP THE TREND OF COOL AND PARTLY CLOUDY WEATHER GOING ALONG WITH
SMALL CHANCES OF SHOWERS IN THE FORECAST AS A NUMBER OF WEAK
DISTURBANCES ROTATE THROUGH THE TROUGH.

EXTENDED PERIOD: UPPER TROUGH WILL EXIT THE AREA SUNDAY WITH
RIDGING BUILDING IN FOR MONDAY. PROGS INDICATE ANOTHER TROUGH
MOVING INTO THE AREA TUESDAY.  ISAACSON

PpDT 4112  ALW 4112  PSC 3111  YKM 0112

.KPDT...WSR-88D...VCP 21/CSR 32...OPERATIONAL

.KPDT...NONE