Damaging Wind in Montana, July 7, 2002

WESTERN MONTANA AND NORTH CENTRAL IDAHO FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MISSOULA MT
244 PM MDT SUN JUL 7 2002

.SHORT TERM...CONVECTION BEGINNING TO KICK IN ACROSS THE CWA AS A
FEW STORMS HAVE FIRED IN THE SOUTHERN CWA. THIS ACTIVITY WILL
CONTINUE TO DEVELOP THROUGH THE COURSE OF THE AFTERNOON AND EARLY
EVENING HOURS...GRADUALLY SPREADING NORTHWARD AHEAD OF APPROACHING
SHORTWAVE. CURRENT FORECAST ON TRACK...AND WILL GO WITH THAT FLOW
INTO THE 4 PM ISSUANCE. SCATTERED TO NUMEROUS THUNDERSTORMS BY THIS
EVENING...WITH THE MAIN THREAT BEING GUSTY DOWNDRAFT WINDS. HAIL
REMAINS A THREAT...BUT LARGE HAIL SHOULD REMAIN ISOLATED AS TEMPS
ALOFT ARE VERY WARM AND INCREASINGLY MOIST. THE ACTIVITY THAT BREWS
THIS AFTERNOON AND EVENING WILL DECREASE IN COVERAGE BY MIDNIGHT...
BUT THEN THE DYNAMICS MOVE IN OVERNIGHT. LARGE UPPER TROUGH WITH
NEGATIVE TILT WILL PROVIDE GOOD DIFFLUENCE ALONG WITH AN 80KT JETLET
POINTING INTO THE NORTHERN CWA OVERNIGHT AS WELL. THE MAIN FORCING
WILL RESIDE ACROSS THE NORTH AND BEST CHANCE FOR PRECIP WILL BE
THERE. ALL THIS FORCING IN THE UPPER LEVELS WILL BE IN PHASE WITH A
A COOL FRONT THAT WILL SLIDE THROUGH NORTH CENTRAL IDAHO OVERNIGHT...
THEN THROUGH WESTERN MONTANA TOMORROW. WILL GO WITH HIGHER POPS THAN
MODEL GUIDANCE SUGGESTS...AS THEY APPEAR TOO LOW. A GOOD CHUNK OF
THE SOUTHERN CWA WILL SEE AN END TO THE PRECIP AFTER TOMORROW
MORNING...ONCE THE FRONT MOVES BY. THE NORTHERN CWA WILL BE UNDER
A COLD POOL TOMORROW AFTERNOON...SO SCATTERED SHOWERS AND EMBEDDED
THUNDERSTORMS WILL BE THE WEATHER FOR THERE. AS THE UPPER LOW PULLS
EASTWARD...AND AFTER SUNSET...ANY CONVECTION WILL QUICKLY DIE OFF.
BY EARLY TUESDAY MORNING...ALL THAT SHOULD BE LEFT WILL BE AN
ISOLATED SHOWER IN THE GLACIER REGION. THE FORECAST WILL BE DRY
TUESDAY THROUGH WEDNESDAY...AS WE WILL TRANSITION BACK INTO A WARM
PATTERN AS UPPER RIDGE BUILDS FROM THE SOUTHWEST. MODELS HAVE BEEN
SHOWING A WARM BIAS...SO WEDNESDAY TEMPS WILL NOT BE TOO HIGH FOR
NOW.

FLASH FLOOD WATCH HAS BEEN ISSUED FOR THE BURNED AREAS IN THE
BITTERROOT MOUNTAINS. CRITERIA CAN EASILY BE MET WITH HIGH PWS AND
THUNDERSTORMS BREWING TO THE SOUTH AND HEADING IN THAT DIRECTION.
DICKSON

.LONG TERM...ALL MODELS CONSISTENT WITH BRINGING IN A HIGH AMPLITUDE
RIDGE OVER THE AREA FOR WARM AND DRY CONDITIONS. TEMPERATURES IN
GOING FORECAST LOOKED TO BE TOO WARM GIVEN THE WARM BIAS OF THE
MRF/AVN. THE LAST EVENT SIMILAR TO THE CURRENT ONE MOS GUIDANCE WAS
5-10 DEGREES TOO WARM. SO DROPPED TEMPS APPROXIMATELY 5 DEGREES
ACROSS THE BOARD. GILCHRIST

.MSO...NONE.

...7-DAY SPOT TEMPS AND POPS...
LIB WBU 061/078 045/083 046/086 37554000
     UUUU 051/092 054/092 055/089 052/088 3300000000
FCA WBU 059/075 044/080 045/083 37665000
     UUUU 045/087 051/087 052/086 050/085 3300000000
POL WBU 059/075 051/079 052/082 37664000
     UUUU 053/085 056/085 057/084 053/083 3300000000
MSO EUU 061/079 046/085 047/088 37652000
     UUUU 046/092 053/092 054/089 052/087 3300000000
HMM EUU 059/078 045/084 046/087 37651000
     UUUU 049/093 054/093 055/090 053/089 3300000000
BTM EUU 054/077 042/083 043/086 37641000
     UUUU 043/087 047/087 048/083 046/082 3300000000
ORO EUU 067/079 052/086 055/092 37531000
     UUUU 056/096 058/096 058/092 055/091 3300000000
GRV EUU 060/076 046/082 049/087 37531000
     UUUU 053/092 053/092 052/090 050/089 3300000000
SMN EUU 057/082 044/085 045/088 37540000
     UUUU 047/091 051/091 052/089 052/088 3300000000

IDZ005>010-MTZ001>007-043-072300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE MISSOULA MT
1224 PM MDT SUN JUL 7 2002

...THUNDERSTORMS DEVELOPING THIS AFTERNOON INTO TONIGHT ACROSS
   NORTH CENTRAL IDAHO AND WESTERN MONTANA...

...HOT DRY WEATHER EXPECTED BY MID-WEEK ACROSS NORTH CENTRAL IDAHO
   AND WESTERN MONTANA....

A LARGE TROUGH OF LOW PRESSURE OFF THE PACIFIC COAST IS ALLOWING
AMPLE AMOUNTS OF SUBTROPICAL MOISTURE TO STREAM INTO NORTH CENTRAL
IDAHO AND WESTERN MONTANA. SCATTERED THUNDERSTORMS HAVE BEGUN TO
DEVELOP IN THIS MOIST AIR MASS...AHEAD OF AN UPPER LEVEL WEATHER
DISTURBANCE. MEANWHILE...SKIES OVER MUCH OF WESTERN MONTANA WERE
MOSTLY SUNNY RESULTING IN GOOD SURFACE HEATING. THIS SURFACE HEATING
WILL ALLOW THE ATMOSPHERE TO DESTABILIZE THROUGH THE DAY. THE
COMBINATION OF SURFACE HEATING...INCREASING ATMOSPHERIC MOISTURE AND
THE APPROACHING WEATHER DISTURBANCE...WILL RESULT IN THE DEVELOPMENT
OF SCATTERED THUNDERSTORMS THROUGH THE AFTERNOON AND EVENING HOURS.

THE POTENTIAL EXISTS FOR SOME OF THESE STORMS TO BECOME QUITE STRONG
WITH GUSTING WINDS AND ISOLATED LARGE HAIL.

CONVECTIVE ACTIVITY WILL CONTINUE OVERNIGHT TONIGHT...BUT OVERALL
STORMS WILL DECREASE IN NUMBERS AND INTENSITY. AS THE WEST COAST LOW
SYSTEM AND ASSOCIATED SURFACE COOL FRONT MOVE INLAND AND THROUGH THE
AREA MONDAY...INCREASING WEST WINDS AND ADDITIONAL THUNDERSTORMS ARE
EXPECTED...ESPECIALLY ACROSS NORTHWEST MONTANA.

A STRONG RIDGE OF HIGH PRESSURE IS FORECASTED TO DEVELOP OVER THE
WESTERN UNITED STATES BY WEDNESDAY...CONTINUING INTO NEXT WEEKEND.
CONDITIONS WILL BE HEATING UP WITH DAYTIME TEMPERATURES EXTENDING
WELL INTO THE 90S...WITH SOME LOCATIONS POSSIBLY REACHING TRIPLE
DIGITS.