Severe Thunderstorm Warning 83, NWS Great Falls, MT

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST
NATIONAL WEATHER SERVICE GREAT FALLS MT
230 PM MDT WED AUG 6 2003

.DISCUSSION...

TONIGHT...CONVECTION CONTINUING IN NORTH CENTRAL MONTANA THIS
AFTERNOON AS THE FIRST IN A SERIES OF WEAK DISTURBANCES MOVES
THROUGH THE STATE. SKIES BEHIND THE PRECIPITATION HAVE BEGUN TO
CLEAR OUT, WHICH WILL HELP TO DESTABILIZE THE ATMOSPHERE. YET
ANOTHER DISTURBANCE NOW LOCATED IN SOUTHERN IDAHO WILL TRAVEL ALONG
THE DIVIDE THIS EVENING PROVIDING FOCUS FOR ANOTHER ROUND OF
THUNDERSTORMS. SEVERAL INGREDIENTS, INCLUDING WIND SHEAR,
INSTABILITY AND SOME LOW LEVEL MOISTURE WILL HELP SET THE STAGE FOR
SEVERE THUNDERSTORM DEVELOPMENT. STRONG DAMAGING WIND GUSTS AND
LARGE HAIL WILL BE THE PRIMARY THREATS THROUGH THE EVENING HOURS.
THE MOST FAVORABLE LOCATION FOR SEVERE THUNDERSTORM DEVELOPMENT WILL
BE FROM HELENA TO GREAT FALLS, UP TO HAVRE. STORMS WILL WEAKEN LATE
TONIGHT AND MOVE OUT OF THE AREA BY MORNING.

THURSDAY AND FRIDAY...SOUTHWEST FLOW ALOFT CONTINUES WITH EMBEDDED
DISTURBANCES RIDING THROUGH THE FLOW. SCATTERED THUNDERSTORMS
SHOULD DEVELOP EACH AFTERNOON AND PROGRESS NORTHEAST. A MORE
PRONOUNCED WAVE COMING UP FROM THE SOUTH THURSDAY NIGHT/FRIDAY AM
TIME FRAME MAY BRING A LITTLE BETTER CHANCE FOR RAIN DURING THAT
TIME. TEMPERATURES WILL REMAIN SLIGHTLY ABOVE NORMAL WITH NOT MUCH
WIND TO SPEAK OF.

SATURDAY AND SUNDAY ...THE STRONG UPPER LEVEL HIGH OVER THE FOUR
CORNERS AREA WITH A RIDGE INTO EASTERN MONTANA WILL REMAIN.
MEANWHILE...AN UPPER LEVEL TROUGH OVER THE WEST COAST WILL CONTINUE
TO BRING MONSOONAL MOISTURE INTO THE AREA. MODELS SHOW A SERIES OF
WEAK DISTURBANCES IN THE FLOW ALOFT. BUT THE BEST CHANCE FOR
CONVECTION WILL BE IN THE AFTERNOON AND EVENING HOURS. TEMPERATURES
ARE TO REMAIN ABOVE NORMAL.

MONDAY THROUGH WEDNESDAY...GFS DOES HINT AT A CHANGE WITH SOME
COOLING AS SURFACE HIGH PROGGED TO DROP OUT OF CANADA IN ADVANCE OF
APPROACHING PACIFIC NORTHWEST TROF. HOWEVER...WILL NOT BITE JUST
YET. WILL KEEP GOING WITH ABOVE NORMAL TEMPERATURES AND MAINLY DRY
UNTIL WE GET A FEW MORE MODEL RUNS TO SHOW CONSISTENCY IN MOVING THE
RIDGE AND BRINGING THIS POSSIBLE PATTERN CHANGE.

.CCF NUMBERS
GTF BB 056/090 056/092 058 05622
    BUUUU 089/061 091/055 088/060 088/063 088 32111000000
CTB BB 053/088 054/086 053 05613
    BUBUU 084/053 087/052 087/055 084/058 084 32---000000
HLN BB 057/091 059/094 059 05622
    BUUUU 092/061 092/055 089/058 086/060 086 211----0000
BZN BB 051/090 053/093 052 05322
    BUUUU 089/051 089/055 090/058 086/061 086 22-11000000
WEY BU 047/077 047/085 041 05111
    BBBUU 082/044 082/050 083/051 076/056 076 21122111110
DLN BB 052/086 054/092 052 05322
    BBUUU 087/050 091/053 089/054 083/057 083 21-11-----0
HVR BB 062/093 060/095 059 05602
    BUBUU 092/063 091/056 090/063 091/066 091 32-11000000
LWT BB 061/091 058/090 056 05412
    BUUUU 086/058 089/057 091/061 087/064 087 22111000000

.TFX...SEVERE THUNDERSTORM WATCH FOR PORTIONS OF SOUTHWEST AND NORTH
       CENTRAL MONTANA THIS EVENING.
       RED FLAG WARNING CONTINUES FOR FIRE WEATHER ZONES 112-118
       THROUGH THIS EVENING.

MTZ008>015-044>055-070010-
HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE GREAT FALLS MT
920 AM MDT WED AUG 6 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND SOUTHWEST MONTANA

.DAY ONE...TODAY

SEVERE THUNDERSTORMS THIS AFTERNOON ARE POSSIBLE. A RED FLAG WARNING
WAS ISSUED FOR THUNDERSTORMS AND HIGH FIRE DANGER. SCATTERED THUNDERSTORMS
WILL DEVELOP ACROSS SOUTHWEST MONTANA THIS AFTERNOON...MOVING NORTH INTO
NORTH CENTRAL MONTANA BY EVENING. SOME OF THESE STORMS WILL BE
ACCOMPANIED BY DAMAGING WINDS AND HAIL. LIGHTNING STRIKES MAY START
FIRES.

RED FLAG WARNING IS CURRENTLY IN EFFECT.  MONITOR NOAA WEATHER
RADIO...YOUR FAVORITE MEDIA OUTLET OR WWW.WEATHER.GOV FOR UPDATES.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THUNDERSTORMS ARE EXPECTED TO DEVELOP THURSDAY AFTERNOON AND
EVENING ACROSS NORTH CENTRAL AND SOUTHWEST MONTANA. SOME OF THESE
STORMS COULD BECOME SEVERE WITH HAIL AND DAMAGING WINDS THE MAIN
THREAT.

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.