Severe Thunderstorm Warning 17, NWS Great Falls, MT

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT930
935 AM MDT TUE JUN 10 2003

.DISCUSSION...WILL UPDATED ZONES AND STATE FORECAST.

FIRST SHORT WAVE MOVING THROUGH ERN HALF OF CWA LEAVING PARTLY SUNNY
SKIES. ENOUGH LOW LEVEL MOISTURE FOR CU TO FORM AND WILL CHANGE
WORDING TO PARTLY CLOUDY BECOMING MOSTLY CLOUDY FOR CENTRAL ZONES.
SUNSHINE SHOULD KICK TEMPERATURES UP TOWARDS FORECASTED HIGHS SO
WILL NOT ADJUST THEM. AM CONCERNED ABOUT POSSIBLE SEVERE
THUNDERSTORMS LATER TODAY. CURRENT FORECAST HAS WORDING TRENDING
TOWARDS IT SO WILL LEAVE IT AS IS. WILL PROBABLY ADJUST TONIGHTS
POPS IN A FEW PLACES. CAMP

TODAY THROUGH WEDNESDAY NIGHT...UPPER TROUGH OVER B.C. WILL SWING
INTO ERN WA AND NRN ID BY LATE AFTERNOON. TROUGH THEN MOVES THROUGH
THE FORECAST AREA TONIGHT/EARLY WEDNESDAY MORNING. MAIN CONCERN
TODAY INTO TONIGHT WILL BE THE THREAT OF SEVERE WEATHER. LATEST SPC
OUTLOOK HAS MOST OF THE GTF FORECAST AREA UNDER A SLIGHT RISK OF
SEVERE THUNDERSTORMS. SITUATION LOOKS RATHER MARGINAL WHEN LOOKING AT
CAPE AND SHEAR VALUES BUT CERTAINLY CAN NOT RULE OUT ISOLATED SEVERE
THUNDERSTORMS. HARD TO SAY HOW CONVECTION WILL PLAY OUT TODAY AND
TONIGHT. ONE SHORTWAVE WILL MOVE THROUGH SOUTHWEST MONTANA THIS
MORNING AND LOCAL RADAR WAS SHOWING SOME SHOWERS/TSTMS OVER SW MT
AHEAD OF FEATURE. LOOKS LIKE ANOTHER SHORTWAVE WILL MOVE THROUGH THE
AREA THIS AFTERNOON WITH THE MAIN TROUGH MENTIONED ABOVE MOVING
THROUGH TONIGHT. CAN EXPECT SHOWERS/THUNDERSTORMS WITH SHORTWAVES AND
ALSO SURFACE TROUGH MOVING THROUGH THIS AFTERNOON AND EVENING. MOS
GUIDANCE FROM DIFFERENT MODELS TENDED TO HAVE HIGHER POPS THAN
INHERITED FORECAST POPS FOR TODAY/TONIGHT. WITH FEATURES MENTIONED
ABOVE AND FAIR AMOUNT OF INSTABILITY WILL LEAN TOWARDS HIGHER MOS
GUIDANCE. LINGERING MOISTURE IN THE N WED/WED NIGHT ALONG WITH SOME
INSTABILITY AND POSSIBLE WEAK SHORTWAVE ACTIVITY COULD LEAD TO
ISOLATED CONVECTION. UPPER RIDGE MOVING OVER AREA LATER WED NIGHT
SHOULD BRING A TEMPORARY END TO THE THREAT OF PRECIPITATION. BLANK

THURSDAY THROUGH SATURDAY...WEAK RIDGING OVER EASTERN MONTANA WITH
SOUTHWEST FLOW ALOFT OVER THE AREA. MAIN STORM TRACK STAYS NORTH OF
MONTANA WITH THE ONLY CHANCES FOR PRECIPITATION COMING FROM
OROGRAPHIC EFFECTS. THUNDERSTORMS OVER THE WESTERN MOUNTAINS EACH
AFTERNOON ARE POSSIBLE, BUT STORMS NOT EXPECTED MAKE IT ONTO THE
PLAINS DUE TO THE LACK OF ANY LARGE SCALE FORCING. TEMPERATURES TO
REMAIN ABOVE SEASONAL AVERAGES DURING THE PERIOD. JCA

SUNDAY THROUGH TUESDAY...GFS MODEL CONTINUES A MOIST AND UNSTABLE
SOUTHWEST FLOW ALOFT OVER REGION WITH AN UPPER LEVEL TROUGH ALONG
THE WEST COAST AND A RIDGE OF HIGH PRESSURE OVER THE MIDWEST. THUS
WILL GO WITH SCATTERED SHOWERS AND THUNDERSTORMS...ESPECIALLY DURING
THE AFTERNOON THROUGH EARLY NIGHTTIME HOURS. TEMPERATURES WILL BE
CLOSE TO SEASONAL AVERAGE. WILLIAMSON DC

.CCF NUMBERS
GTF WE 072/048 073/046 076 0465-
    BBBBB 049/076 049/078 048/074 047/074 047 -00--024444
CTB WE 067/047 068/045 073 04651
    BBBBB 043/074 048/075 047/070 046/070 046 10033-24444
HLN EB 075/049 076/049 077 0454-
    BBBBB 047/077 050/080 050/076 049/076 049 -0033134444
BZN BB 075/044 074/043 077 04440
    BBBEE 049/078 047/078 045/075 044/075 044 00011124444
WEY BB 068/037 067/034 070 04240
    BBBEE 047/070 042/071 042/066 041/066 041 02212224444
DLN BB 075/043 074/043 075 04220
    BBBEE 047/076 045/075 045/072 044/072 044 02222234444
HVR TE 073/049 073/049 077 04663
    BBBBB 052/082 053/082 050/077 049/077 049 10000003333
LWT EB 067/046 070/045 077 0456-
    BBBBB 049/080 050/075 047/070 046/070 046 -0000004444

.TFX...NONE.

MTZ008>015-044>055-110010-
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREAT FALLS MT
610 AM MDT TUE JUN 10 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND SOUTHWEST MONTANA

.DAY ONE...TODAY

SEVERE THUNDERSTORMS ARE POSSIBLE ACROSS THE AREA THIS AFTERNOON AND
EVENING. PRIMARY THREATS FROM THE THUNDERSTORMS WILL BE GUSTY WINDS
AND LARGE HAIL. PLEASE REFER TO GTFSPSTFX FOR FURTHER INFORMATION.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

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