Damaging Winds in Washington, May 24, 2001

EASTERN WASHINGTON AND NORTH IDAHO AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WASHINGTON
230 PM PDT THU MAY 24 2001

UPPER LEVEL SW FLOW PREVAILS OVER THE INLAND NORTHWEST THIS AFTERNOON
WITH A SHORTWAVE TROF SPREADING MID-UPPER LEVEL CLOUDS ACROSS THE
CASCADES. THIS FEATURE WILL CONTINUE TO LIFT ACROSS SRN BC AND SKIRT
THE NRN TIER ZONES OVERNIGHT WITH A DEEP LAYER OF SHEER. EVEN THOUGH
INSTABILITY IS WEAKER TODAY...DYNAMICS ARE STRONGER AND WILL WORD
ISOLATED THUNDERSTORMS FROM THE HIER ELEVATIONS OF THE NRN CASCADES
TO NORTH IDAHO. SOME COULD PRODUCE STRONG GUSTY WINDS. THE BEST
INSTABILITY LIES ACROSS SE WA AND THE SRN PANHANDLE. CU IS ALREADY
POPPING ACROSS THE MTNS OF ERN OREGON AND CENTRAL ID. WITH THE S/SW
MID LEVEL FLOW...EXPECT THIS CONVECTION TO ADVECT INTO THE WA BLUES
AND LC VALLEY THIS EVENING...REACHING THE CENTRAL PANHANDLE MTNS
OVERNIGHT AND LINGER INTO THE MORNING. SPC IS WATCHING THE INLAND NW
AND THE POTENTIAL FOR SEVERE THUNDERSTORMS DOES EXIST. THE LOW LEVEL
THERMAL RIDGE WILL STILL HOVER FROM EXTREME ERN WA INTO WRN MT INTO
FRIDAY MORNING...MAKING FOR ANOTHER BALMY EVENING. THE WEAK MARINE
PUSH WILL KEEP A W/NW FLOW IN THE CASCADES THROUGH THE NIGHT.

THE ETA KEEPS HIGH INSTABILITY LINGERING IN THE IDAHO PANHANDLE
FRIDAY AND INTO FRIDAY EVENING. THE UPPER FLOW WILL TURN TO A FLAT
RIDGE PATTERN WITH NO SIGNIFICANT WAVES. THUS ANY CONVECTION THAT
WOULD FIRE WOULD BE PULSE-LIKE IN THE LATE AFTERNOON AND
EVENING...ESPECIALLY ALONG THE LOW LEVEL THERMAL RIDGE WHICH WILL
REMAIN PARKED ALONG THE WA/ID BORDER...ALBEIT NOT AS INTENSE. WILL
WORD A SLIGHT CHANCE OF THUNDERSTORMS/SHOWERS FOR THIS AREA. TEMPS
WILL COOL SLIGHTLY...BUT STILL REMAIN IN THE 80S.

A WAVE FROM THE CUTOFF LOW OFF OF CA WILL BREAK OFF IN THE SW FLOW ON
SATURDAY WITH A SURGE OF SUBTROPICAL MOISTURE. THIS COMBO WILL LIFT
ACROSS OREGON AND SHOULD REACH SE WA AND THE SRN PANHANDLE BY LATE
AFTERNOON. UPPER LEVEL DYNAMICS LOOK GOOD...YET SOME MID LEVEL
SUBSIDENCE WAS NOTED THROUGH 00Z SUN. EXPECT MOST OF THE ACTION TO
TAKE PLACE SAT EVE. BUT WILL WORD AN INCREASE OF CLOUDS ACROSS THE SE
PORTION OF THE FORECAST AREA WITH THE BEST CHANCE OF CONVECTION
AROUND THE LWS AREA. AGAIN SLIGHT COOLING IN TEMPS...BUT STILL
REMAINING ABOVE NORMAL FOR THE START OF THE HOLIDAY WEEKEND. RLF.

IN THE EXTENDED...A DECENT NEGATIVELY TILTED TROF COMES ACROSS THE
DISTRICT ON SUNDAY BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS TO
MOST AREAS ALONG WITH SLIGHTLY COOLER TEMPS. ON MONDAY...A RIDGE
BUILDS IN FROM THE WEST WHICH SHOULD DRY THINGS OUT EXCEPT OVER THE
EASTERN MOUNTAINOUS AREAS WHICH COULD SEE A FEW SHOWERS. ON TUESDAY
THROUGH WEDNESDAY...RIDGE ESTABLISHES ITSELF ACROSS THE PACIFIC
NORTHWEST KEEPING THE FORECAST AREA DRY. ON THURSDAY...ANOTHER LOW
WILL BEGIN TO MOVE ACROSS THE DISTRICT WHICH WILL BRING ANOTHER
SLIGHT CHANCE FOR SHOWERS TO THE MOUNTAINOUS AREAS.

...THE INFORMATION IN THIS PRODUCT CONCERNING WARNINGS AND FORECASTS
IS VALID ONLY AT THE TIME OF ISSUANCE. THE LATEST WARNING AND
FORECAST INFORMATION WILL BE FOUND IN THE APPROPRIATE PRODUCTS...

GEG 057/086/053/082 1110
CQV 053/090/051/084 2110
SPT 053/083/052/080 2110
COE 054/085/051/081 1110
WWP 052/083/050/080 2112
LWS 061/088/058/086 2113
PUW 057/084/054/081 1111
EAT 058/088/057/087 0000
MWH 056/089/054/088 0000

.GEG...NONE.