Severe Thunderstorm Warning 56, NWS Great Falls, MT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
535 PM MDT THU JUN 28 2007

UPDATE TO AVIATION SECTION ONLY.

.DISCUSSION...
TONIGHT THRU SATURDAY...SOUTHWESTERLY FLOW ALOFT WILL CONTINUE OVER
THE FORECAST AREA DURING THIS TIME. RECENT LOW LEVEL EASTERLY FLOW
HAS INCREASED BOUNDARY LAYER MOISTURE THROUGHOUT THE REGION...WHICH
WILL BE AN IMPORTANT INGREDIENT FOR POSSIBLE THUNDERSTORMS THIS
EVENING...AS WELL AS TOMORROW. WIND SHEAR THROUGH THE MID LAYERS
THROUGH LATE TOMORROW EVENING APPEARS TO BE SUFFICIENT FOR
SUSTAINING ISOLATED SUPERCELL THUNDERSTORMS...WITH THE GREATEST
THREAT BEING DAMAGING WINDS AND HAIL. IN ADDITION...A SURFACE COLD
FRONT IS ANTICIPATED TO PASS THROUGH THE AREA FRIDAY EVENING...WITH
FRIDAY AFTERNOON TEMPERATURES WARMING TO WELL ABOVE THE SEASONAL
AVERAGE. COOLER AIR WILL BE IN PLACE ON SATURDAY...WITH LINGERING
RAIN SHOWER ACTIVITY OVER THE CENTRAL AND SOUTHWEST MOUNTAINS. ZUMPFE

SATURDAY NIGHT THROUGH THURSDAY...AN UPPER LEVEL LOW PRESSURE SYSTEM
WILL BE APPROACHING THE WEST COAST SATURDAY NIGHT AND SUNDAY. A
SERIES OF WEAK DISTURBANCES WILL BE MOVING THROUGH THE SOUTHWEST
FLOW AHEAD OF THIS SYSTEM. THIS WILL KEEP THE AIRMASS UNSETTLED
ALTHOUGH CONDITIONS WILL REMAIN QUITE DRY AND THE CHANCE OF
PRECIPITATION WILL STAY LOW. THE BEST CHANCE FOR PRECIPITATION AND
THUNDERSTORMS WILL OCCUR MONDAY AS THE LOW PRESSURE SYSTEM MOVES
ACROSS THE CANADIAN ROCKIES. A FLAT UPPER LEVEL RIDGE WILL THEN
BEGIN TO BUILD AND THE AIRMASS WILL BECOME DRIER AND MORE STABLE.
TEMPS WILL TREND UPWARD THROUGH MONDAY AND STAY WELL ABOVE NORMALS.
SLIGHT COOLING WILL OCCUR TUESDAY THROUGH THURSDAY BUT TEMPS WILL
STILL REMAIN ABOVE NORMALS. ZELZER

&&

.AVIATION...
UPDATED 2335Z.
HIGH PRESSURE ALOFT AND AT THE SURFACE WILL PERSIST. THE AIRMASS IS
VERY WARM AND DRY AT THE LOWER LEVELS. ISOLATED CONVECTIVE ACTIVITY
IS POSSIBLE OVER HIGHER TERRAIN THROUGH 06Z. VFR CONDITIONS PREVAIL
WITH MVFR CONDITIONS IN THE VICINITY OF THUNDERSTORMS. THUNDERSTORMS
TO INCREASE IN COVERAGE WITH A FEW SEVERE WITH GUSTY WINDS AND HAIL
LATE FRIDAY AFTERNOON AND EVENING. CAMP

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  61  91  57  83 /  20  30  30  10
CTB  56  87  53  79 /  30  30  30  10
HLN  60  92  55  82 /  20  20  20  10
BZN  57  93  51  82 /  10  20  30  10
WEY  46  83  42  80 /  10  10  20  10
DLN  55  87  49  82 /  10  20  20  10
HVR  59  93  57  84 /  20  20  40  10
LWT  58  90  56  79 /  20  20  30  10

&&

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

&&

SHORT TERM...ZUMPFE
LONG TERM...ZELZER
AVIATION...CAMP

WEATHER.GOV/GREATFALLS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREAT FALLS MT
511 AM MDT THU JUN 28 2007

MTZ008>015-044>055-291200-
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-
511 AM MDT THU JUN 28 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA.

.DAY ONE...TODAY AND TONIGHT

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER FOR TODAY AND
TONIGHT IS LOW.

ISOLATED SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER THE REGION
TOWARDS EVENING. A FEW THUNDERSTORMS COULD PRODUCE STRONG WIND
GUSTS AND SMALL HAIL.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER THE REGION
DURING THE AFTERNOON AND EVENING HOURS ON FRIDAY. A FEW
THUNDERSTORMS COULD BE SEVERE...WITH DAMAGING WINDS AND LARGE
HAIL. THE THREAT FOR THE STRONGEST STORMS IS EXPECTED TO BE OVER
NORTH CENTRAL MONTANA ON FRIDAY EVENING...WHERE THERE IS A SLIGHT
RISK OF SEVERE THUNDERSTORMS.

.SPOTTER INFORMATION STATEMENT...

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