Severe Thunderstorm Warning 2, NWS Great Falls, MT

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MONTANA
946 AM MDT SAT MAY 8 2004

WILL UPDATE ZONE AND STATE FORECASTS

.DISCUSSION...

UPDATE TO TODAY...MAIN FORECAST PROBLEM TODAY WILL AGAIN BE TIMING
AND LOCATION OF CONVECTION. A WEAK SHORT WAVE TROUGH AND MARGINAL
ELEVATED INSTABILITY ARE PRODUCING SCATTERED THUNDERSTORMS THIS
MORNING OVER PARTS OF CENTRAL AND SOUTHWESTERN MONTANA. THINK THERE
WILL BE A BRIEF BREAK IN ACTIVITY LATE THIS MORNING AND EARLY THIS
AFTERNOON AS SUBSIDENCE BEHIND THE DEPARTING SHORT WAVE TROUGH
OVERTAKES THE FORECAST AREA. MOST AREAS WILL ALSO SEE A PARTIAL
CLEARING TREND DURING THIS TIME PERIOD...SO EXPECT SOME DECENT
TEMPERATURE RECOVERY. BY THE MIDDLE OF THIS AFTERNOON...A SECOND
PIECE OF ENERGY WILL APPROACH WESTERN AND CENTRAL MONTANA. AN UPPER
LEVEL JET STREAK WILL ALSO PUT MUCH OF CENTRAL MONTANA IN A REGION
OF FAVORABLE LIFT. THE ATMOSPHERE WILL BECOME SOMEWHAT UNSTABLE BY
THIS TIME...SO EXPECT ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO
DEVELOP LATER THIS AFTERNOON. HAVE MADE SOME MINOR ADJUSTMENTS TO
POPS AND CLOUD COVER TO COMPENSATE FOR THE EXPECTED DEVELOPMENT.
TEMPERATURES AND WINDS LOOK GOOD IN THE GOING FORECAST. SCHAUMANN

TODAY AND TONIGHT...ANOTHER WARM AND UNSTABLE DAY IN ST0RE FOR
CENTRAL MONTANA. A BROAD UPPER LEVEL RIDGE IS OVER THE NORTHERN
ROCKIES WITH SOUTHWEST FLOW ALOFT OVER THE STATE. SATELLITE IS
SHOWING A DISTURBANCE OVER IDAHO THAT WILL MOVE ACROSS THE STATE
TODAY. SCATTERED THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS OF
CENTRAL MONTANA BY AFTERNOON AND MOVE INTO EASTERN MONTANA DURING THE
EVENING. A PACIFIC COLD FRONT WILL PUSH THROUGH CENTRAL MONTANA
OVERNIGHT WITH GUSTY WINDS AND DRYING CONDITIONS.

SUNDAY THROUGH MONDAY NIGHT...THE FORECAST BEGINS TO GET INTERESTING
AS A SHORTWAVE SWINGS THROUGH ALBERTA ON SUNDAY. A CANADIAN COLD
FRONT WILL APPROACH THE BORDER DURING THE DAY FOR A SLIGHT CHANCE OF
SHOWERS...THEN MOVES INTO MONTANA BY EVENING. WINDS WILL SWITCH TO
THE NORTH AND ADVECT COOLER TEMPERATURES INTO NORTH CENTRAL MONTANA
OVERNIGHT. THE FUN STARTS ON MONDAY AS THE ALBERTA TROUGH PROGRESSES
EAST AND AN EASTERN PACIFIC UPPER LOW MOVES INLAND. ENERGY FROM THIS
LOW BEGINS TO DUMBBELL OVER THE PACIFIC NORTHWEST AS A FAST MOVING
SHORTWAVE DIVES SOUTHEAST FROM THE GULF OF ALASKA. A SURFACE LOW
DEVELOPS OVER THE GREAT BASIN ON MONDAY AND MOVES TO NORTHERN WYOMING
MONDAY NIGHT. WIDESPREAD PRECIPITATION IS EXPECTED TO DEVELOP OVER
CENTRAL AND SOUTHWEST MONTANA BY MONDAY NIGHT. WARM SOUTHWEST FLOW
ALOFT WILL KEEP FREEZING LEVELS RELATIVELY HIGH...SO EXPECT MAINLY
RAIN. MPJ

TUESDAY THROUGH THURSDAY...A STRONG AREA OF LOW PRESSURE IS PROGGED
BY THE GFS TO BE NEAR NORTHEAST WY BY EARLY TUESDAY. AS A RESULT...
LIKELY POPS WILL CONTINUE OVER MUCH OF THE CWA ON TUESDAY.
ADDITIONALLY...A LATE SEASON ARCTIC COLD FRONT WILL BEGIN TO PUSH
SOUTH INTO NORTH CENTRAL MONTANA. EXPECT TEMPERATURES TO BE FALLING
THROUGHOUT THE DAY ON TUESDAY...WITH RAIN CHANGING TO SNOW AT ALL
ELEVATIONS TUESDAY AFTERNOON OVER NORTH CENTRAL MONTANA. GUSTY NORTH
WINDS WILL ACCOMPANY THE ARCTIC COLD FRONT. SNOW WILL LIKELY FALL
ACROSS MUCH OF THE REGION TUESDAY NIGHT...WITH ACCUMULATIONS LIKELY.
ON WEDNESDAY...A COLD NORTHERLY FLOW WILL CONTINUE OVER THE REGION...
ALLOWING FOR UPSLOPE SNOW TO CONTINUE. I HAVE TEMPERATURES UP INTO
THE 40S FOR WEDNESDAY...BUT THIS MAY BE TOO WARM...ESPECIALLY OVER
THE NORTH. FOR THURSDAY...THE FLOW ALOFT IS OUT THE NORTHWEST...AND A
WEAK WEATHER DISTURBANCE WILL MOVE SOUTH THROUGH THE FLOW. AS A
RESULT...A FEW AFTERNOON SHOWERS ARE POSSIBLE. OVERALL...TEMPERATURES
WILL BE UNSEASONABLY COLD TUESDAY THROUGH THURSDAY...WITH SOME RECORD
LOWS POSSIBLE. MANY LOCATIONS WILL AVERAGE TEMPERATURES BETWEEN 20
AND 25 DEGREES BELOW NORMAL BY WEDNESDAY.

FOR FRIDAY AND SATURDAY...A NEW UPPER LEVEL RIDGE OF HIGH PRESSURE
WILL BUILD OVER THE REGION. THIS WILL ALLOW TEMPERATURES TO WARM BACK
UP TO NEAR NORMAL BY SATURDAY...ALONG WITH DRY CONDITIONS. BRUSDA

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF BB 075/043 064/035 062 05310
    BOEBB 035/043 028/044 027/052 031/057 033 02673212200
CTB BB 069/041 057/032 057 05312
    BOEBB 035/038 026/041 025/049 029/054 031 00563-02-00
HLN BB 077/044 068/040 064 05320
    BREBB 038/049 032/046 031/056 035/057 037 02673212200
BZN BB 076/039 068/036 065 05310
    BREBB 035/049 028/047 027/053 031/056 033 02464212200
WEY EB 066/038 059/027 059 05220
    BOEEB 031/046 033/040 028/046 036/053 038 03364223300
DLN BB 072/039 065/032 064 05210
    BOEBB 034/049 029/046 028/053 032/056 034 02553212200
HVR BB 078/046 064/034 061 05322
    BOEBB 039/039 028/042 027/053 031/058 033 00664-02000
LWT BB 072/041 063/035 061 05420
    BREBB 035/043 026/043 025/051 029/056 031 01674312200

&&

.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREAT FALLS MT
600 AM MDT SAT MAY 8 2004

MTZ008>015-044>055-091110-
BEAVERHEAD-NORTHERN ROCKY MOUNTAIN FRONT-EASTERN
GLACIER-HILL-CASCADE-CHOUTEAU-CENTRAL AND SOUTHERN LEWIS AND
CLARK-MADISON-TOOLE-LIBERTY-EASTERN PONDERA-BLAINE-SOUTHERN ROCKY
MOUNTAIN FRONT-EASTERN TETON-JUDITH
BASIN-FERGUS-JEFFERSON-BROADWATER-MEAGHER-GALLATIN-
600 AM MDT SAT MAY 8 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND SOUTHWEST
MONTANA

.DAY ONE...TODAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. SCATTERED
THUNDERSTORMS WILL DEVELOP ACROSS NORTH CENTRAL AND SOUTHWEST
MONTANA THIS AFTERNOON. SOME STORMS IN EASTERN PORTIONS OF CENTRAL
MONTANA MAY PRODUCE GUSTY WINDS TO 50 MPH THIS AFTERNOON.

NO WATCHES, WARNINGS, OR ADVISORIES CURRENTLY IN EFFECT

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. RAIN AND
SNOW IS LIKELY ACROSS MUCH OF NORTH CENTRAL AND SOUTHWEST MONTANA
MONDAY NIGHT AND TUESDAY. TEMPERATURES ON TUESDAY AND WEDNESDAY WILL
BE WELL BELOW NORMAL.

.SPOTTER INFORMATION STATEMENT...

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