Severe Thunderstorm Warning 45, NWS Great Falls, MT

SOUTHWEST AND NORTH CENTRAL MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
215 PM MDT THU JUN 19 2003

.DISCUSSION...

TONIGHT THROUGH SATURDAY...RATHER MOIST SW FLOW ALOFT WILL CONTINUE
OVER THE AREA INTO THE WEEKEND. LATE FRIDAY NIGHT AN UPPER TROUGH
MOVES INTO MT WEST OF THE CONTINENTAL DIVIDE THEN MOVES THROUGH THE
FORECAST AREA ON SAT. AT THE SURFACE A TROUGH FROM CENTRAL MT
THROUGH SW MT WILL NOT MAKE MUCH PROGRESS E OVERNIGHT BUT THEN WILL
ACCELERATE INTO THE ERN PLAINS OF MT FRI AFTERNOON AS DOWNSLOPE
INCREASES OVER THE E SLOPES OF THE ROCKY MOUNTAINS. ONE AREA OF
CONVECTION WILL SPREAD NE FROM SW MT TO N CENTRAL MT THU AFTERNOON
AND EVENING. A SHORTWAVE MAY SPAWN ANOTHER ROUND OF CONVECTION OVER
THE FAR WRN ZONES LATE TONIGHT WHICH WILL SPREAD E ON FRI. EXPECT
PRECIPITATION TO DIMINISH W TO E FRI AFTERNOON AND EVENING AS
SHORTWAVE MOVES E OF AREA AND DOWNSLOPE INCREASES. ON SAT THERE WILL
BE INSTABILITY AS THE UPPER TROUGH MOVES THROUGH THE AREA. BUT ON
THE OTHER HAND LOW LEVEL DOWNSLOPE WINDS WILL BE BLOWING OVER THE
PLAINS. ETA AND GFS DIFFER ON QPF FOR AREA ON SAT WITH GFS DRIER.
WILL CONTINUE WITH CHANCE POPS N BUT LOWER FAR S TO SLIGHT CHANCE AS
MOST MOISTURE AND DYNAMICS STAY N OF AREA. AS FOR SEVERE
WEATHER..SEVERE TSTM WATCH IS IN PLACE THROUGH THE EARLY EVENING
HOURS OF THU AND MAY NEED TO BE EXPANDED N AND/OR E DURING THE
EVENING. FRI AFTERNOON SURFACE TROUGH AND GREATEST INSTABILITY
ARE E OF FORECAST AREA BUT THERE STILL IS AN OUTSIDE CHANCE OF SEVERE
TSTMS OVER FERGUS AND BLAINE COUNTIES. BLANK

.SATURDAY NIGHT AND SUNDAY...UPPER TROF MOVES OVER THE AREA SATURDAY
NIGHT CONTINUING CONVECTIVE ACTIVITY. BY SUNDAY...FLOW ALOFT BECOMES
MORE WESTERLY ALLOWING FOR SOMEWHAT OF A RESPITE FROM SIGNIFICANT
WEATHER. ENOUGH INSTABILITY THOUGH FOR A SLIGHT CHANCE OF SHOWERS OR
THUNDERSTORMS.

.MONDAY THROUGH THURSDAY...CONVECTIVE PATTERN RETURNS MONDAY
THROUGH WEDNESDAY AS AN UPPER LOW MOVES ACROSS IDAHO AND NORTHERN
WYOMING. LOW LIFTS OUT THURSDAY LEAVING CWA UNDER NORTHWEST FLOW
ALOFT. CHANCE OF SHOWERS WILL CONTINUE EACH DAY.

.CCF NUMBERS
GTF TE 054/070 046/065 043 04664
    BBBBB 066/043 065/044 064/047 066/046 070 33233334433
CTB TE 055/064 044/062 041 04761
    BBEBB 063/045 061/044 063/045 065/045 068 33233333322
HLN TE 058/071 047/066 046 04665
    BBBBB 065/045 066/046 066/050 067/049 072 33233444433
BZN TB 051/072 044/065 040 04566
    BBBBB 065/040 064/043 066/046 067/045 069 33233444444
WEY TB 042/066 038/058 031 04467
    BBBBB 060/038 059/039 058/039 056/037 062 23233444455
DLN TB 054/067 044/064 038 04666
    BBBBB 064/040 064/042 066/047 065/042 071 23233444433
HVR TE 057/077 049/069 045 04664
    BBBBB 067/048 069/049 068/050 071/049 074 33233443333
LWT TB 054/075 046/065 042 04566
    BBBBB 062/044 061/045 063/047 065/045 068 33233444444

.TFX...SEVERE THUNDERSTORM WATCH THROUGH 7 PM SW MT AND PORTIONS OF
CENTRAL MT (ZONES 8/15/52 THROUGH 55/14/12/50).

MTZ008>015-044>055-200010-
HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE GREAT FALLS MT
140 PM MDT THU JUN 19 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL AND SOUTHWEST
MONTANA

.DAY ONE...TODAY

A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED FOR SOUTHWEST MONTANA AND
PORTIONS OF CENTRAL MONTANA. SCATTERED THUNDERSTORMS ARE EXPECTED
ACROSS THE AREA THIS AFTERNOON THROUGH EARLY EVENING. SOME STORMS
MAY BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

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.