Severe Thunderstorm Warning 9, NWS Boise, ID

SOUTHWEST IDAHO/SOUTHEAST OREGON AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BOISE IDAHO
215 PM MDT THU JUN 27 2002

...VIGOROUS COOL PACIFIC FRONT FRIDAY EVENING...
...BREEZY SATURDAY AFTERNOON AND BREEZY TO WINDY SUNDAY AFTERNOON...

IN THE SHORT TERM, THUNDERSTORMS THIS EVENING EXPECTED IN THETA-E
RIDGE OVER SW IDAHO IN ARC SHAPE ACROSS ERN SW HIGHLANDS AND MAGIC
VLY NNWWRD INTO WEST CENTRAL MOUNTAINS AS A KICKER/TRIGGER UPPER
VORT (400MB) NEAR IDAHO-NV-UTAH TRI-STATE AREA SHIFTS N THRU SUNSET
THEN SHIFTS NE IN RESPONSE TO INCREASING SW FLOW THRU PACNW.
CONVECTIVE PARAMETERS THIS EVENING SOMEWHAT LESS IMPRESSIVE THAN
LAST EVENING WITH CAPE 2K JOULES/KG AND LI -2 TO-4 BUT STILL ENOUGH
TO EXPECT ISOLATED GUSTS AROUND 50 MPH WITH STRONGER/BETTER
ORGANIZED CELLS.  MID LAYER CAPPING IN SE OREGON-OWHYEE MTNS
EXPECTED TO INHIBIT CONVECTION IN SE OREGON AND FAR SW PART OF SW
HIGHLANDS, EXCEPT MAYBE EASTERN BAKER CO., THIS EVENING.

OTHERWISE TONIGHT AND FRIDAY THE UPPER LOW NEAR 50N 140 W, WHICH HAS
A 130+KT JET S OF IT ALONG 45N, SENDS A WELL DEVELOPED TROF AND COOL
FRONT INTO WA/ORE FRIDAY.  CD FRONT EXPECTED INTO BURNS FRIDAY LATE
AFTERNOON WITH THERMAL ENHANCED CDFNT WINDS INTO BREEZY CATEGORY FOR
HARNEY COUNTY.

FOR FRIDAY EVENING AND NIGHT VERY HIGH PW AIR (.8-1.25) MOVES OVER
ERN OREGON AND SW IDAHO IN ADVANCE OF THE FRONT.  ALOFT THE UPPER
TROF GOES NEGATIVELY TILTED.  FORECAST SOUNDINGS INDICATE SCATTERED
THUNDERSTORMS ARE POSSIBLE NORTH OF A BURNS-BOISE-ROGERSON ZONE WITH
FORECAST CAPE IN THE 500-1000 JOULE/KG RANGE AND LI TO -2C.  MUCH
STRONGER DYNAMIC SUPPORT FRIDAY NIGHT IS OFFSET BY NOT AS MUCH
INSTABILTY YESTERDAY OR TODAY.  HI PW AND FORCING BUT FAST MOVING
CELLS MEANS ANY TRAINING CELLS NEED TO BE WATCHED FOR FLASH FLOOD
POTENTIAL.  EXPECT NUMEROUS RAIN SHOWERS AND SCT TS NORTH FRIDAY
NIGHT WITH SCT SHOWERS AND TS SOUTHERN AREAS OVERNIGHT.  FRIDAY
EVENING THE CDFNT SHIFTS EAST INTO SW IDAHO FOR EVENING NW WINDS
10-20 MPH TIL SUNSET.  ON SATURDAY THE FRONT SHOULD REACH TWF ABOUT
9Z WITH SE OREGON SHOWERS TAPERING OFF TO ISOLATED IN THE MORNING
WEST AS THE TROF HAS YET TO CROSS THE AREA.  UPPER TROF DOES CROSS
INTO SOUTH CENTRAL ID MIDDAY SATURDAY FOR SCATTERED SHOWERS AND A
SLIGHT CHC OF THUNDERSTORMS--BOISE 00Z SUNDAY SOUNDING IN MODERATELY
UNSTABLE.  SHOULD ALSO DEVELOP BREEZY CONDITIONS SATURDAY AFTERNOON
FROM MOUNTAIN HOME THRU TWIN FALLS.

A DEVELOPING SHORTWAVE NEAR 45N 150W AT 19Z TODAY ZIPS THROUGH THE
AREA SUNDAY WITH BUILDINDG HIGH PRESSURE AND BREEZY TO WINDY
WESTERLY FLOW DEVELOPING ACROSS THE REGION.  CLOUDS ACROSS THE
NORTH WITH ISOLATED SHOWERS IN THE N MOUNTAINS AND PARTLY CLOUDY
ACROSS THE SOUTH.

AN UPPER LOW APPROACHING THE ALEUTIAN ISLANDS THIS AFTERNOON FOLLOWS
THE DEVELOPING SHORTWAVE INTO THE NW PROBABLY FOR TUESDAY BUT PLAN
TO BROAD BRUSH MON-WED WITH FAST FLOW...SOME CLOUDS AT TIMES ACROSS
THE NORTH BUT MOSTLY CLEAR SOUTH MONDAY-WED...WITH AVERAGE TEMPS.
DRY AND MILDER WESTERLY FLOW BY THURSDAY/INDEPENDANCE DAY.

.BOI...NONE.

MILLS