Special Weather Statement, NWS Great Falls, MT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
257 PM MDT TUE JUN 9 2015

.DISCUSSION...

TONIGHT THROUGH THURSDAY...A WEAK SLOW-MOVING DISTURBANCE WILL
CONTINUE TO MOVE EAST ACROSS SOUTHWEST MONTANA INTO SOUTH CENTRAL
AND CENTRAL MONTANA THIS EVENING, BRINGING NUMEROUS SHOWERS AND
THUNDERSTORMS. SOME STORMS WEST OF THE CONTINENTAL DIVIDE HAVE
ALREADY BROUGHT HAIL TO SOME AREAS. BRIEF HEAVY RAIN AND GUSTY
WINDS ARE ALSO POSSIBLE. THE SLOW MOVEMENT OF THE STORMS MAY CAUSE
ISSUES IF RAIN LINGERS OVER A GIVEN AREA FOR A PERIOD OF TIME. ALL
OF THESE FACTORS WILL BE MONITORED FOR POSSIBLE STATEMENTS. ONCE
THE STORMS MOVE INTO CENTRAL MONTANA (MAINLY SOUTHEAST OF A GREAT
FALLS TO HAVRE LINE) THE DRIER AIRMASS WILL LIKELY MAKE GUSTY
WINDS THE MAIN THREAT. A FEW STORMS MAY LINGER AFTER MIDNIGHT IN
THESE AREAS, BUT ACTIVITY WILL LIKELY BE WEAK. HOWEVER, ANOTHER
DISTURBANCE WILL MOVE ALONG THE CANADIAN BORDER OVERNIGHT INTO
WEDNESDAY MORNING, WHICH WILL BRING SOME WEAK THUNDERSTORMS TO
THE HI- LINE AREA. THIS DISTURBANCE WILL ALSO PUSH THE FRONTAL
BOUNDARY SOUTH FROM A CUT BANK TO LEWISTOWN LINE (TODAY) INTO THE
BOULDER AND WHITE SULPHUR SPRINGS AREA ON WEDNESDAY. THIS WILL
COOL TEMPERATURES ABOUT 10 DEGREES OVER THOSE TODAY, AND IT WILL
KEEP THE FOCUS FOR THUNDERSTORM ACTIVITY ACROSS SOUTHWEST MONTANA
ONCE AGAIN DURING THE AFTERNOON AND EVENING HOURS. ONCE THE
DISTURBANCE EXITS THE AREA WEDNESDAY NIGHT, THE UPPER LEVEL RIDGE
WILL REBUILD INTO MONTANA FROM THE WEST, WHICH WILL BRING QUIETER
AND WARMER WEATHER TO THE FORECAST AREA. HIGHS ARE EXPECTED TO BE
ABOUT 5 TO 10 DEGREES WARMER THAN THOSE ON WEDNESDAY, WHICH WOULD
MAKE THEM ABOUT 10 TO 15 DEGREES ABOVE NORMAL.  COULSTON

THURSDAY NIGHT THROUGH TUESDAY...EXPECT FRIDAY TO BE A RATHER
WARM DAY OVER MUCH OF THE REGION...AS WEAK SHORTWAVE RIDGING
RESIDES OVER THE REGION. BY FRIDAY NIGHT...AN UPPER LEVEL
DISTURBANCE WILL BE APPROACHING THE NORTHWEST PORTIONS OF THE
REGION...WHILE A WEAK PACIFIC COOL FRONT MOVES EASTWARD THROUGH
THE AREA ON SATURDAY. AS A RESULT...EXPECT SOME COOLER
TEMPERATURES TO RESIDE OVER THE REGION THIS WEEKEND AND INTO EARLY
NEXT WEEK...WITH TEMPERATURES NEAR NORMAL. THERE WILL BE A CHANCE
FOR A PASSING SHOWER/THUNDERSTORM FROM SATURDAY THROUGH TUESDAY.
OVERALL...OTHER THAN FRIDAY BEING A VERY WARM DAY...NO SIGNIFICANT
IMPACTS IN TERMS OF VERY WARM TEMPERATURES OR HEAVY PRECIPITATION
IS EXPECTED FROM SATURDAY THRU TUESDAY. BRUSDA

&&

.AVIATION...
UPDATED 1738Z.

THE AIRMASS WILL BE UNSTABLE THIS AFTERNOON AND EVENING. SHOWERS
AND THUNDERSTORMS WILL DEVELOP ACROSS SOUTHWEST MONTANA AND MOVE
NORTHEAST TOWARDS FERGUS COUNTY. LOCAL GUSTY WINDS TO 45 KTS.
THUNDERSTORMS ACTIVITY WILL DIMINISH AFTER 06Z WEDNESDAY. MVFR
CONDITIONS ARE POSSIBLE NEAR SHOWERS AND THUNDERSTORMS. ELSEWHERE
VFR CONDITIONS WILL PREVAIL THROUGH THE NEXT 24 HOURS.

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  55  77  52  84 /  20  20  20  10
CTB  50  73  49  82 /  10  10  10  10
HLN  59  83  55  86 /  40  30  20  10
BZN  54  80  49  79 /  50  60  40  10
WEY  44  72  42  71 /  50  70  40  20
DLN  52  78  50  79 /  50  60  40  10
HVR  55  77  49  83 /  30  20  10  10
LWT  57  74  50  77 /  40  30  20  10

&&

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

WEATHER.GOV/GREATFALLS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
359 PM MDT TUE JUN 9 2015

MTZ014-092230-
CENTRAL AND SOUTHERN LEWIS AND CLARK-
359 PM MDT TUE JUN 9 2015

...A STRONG THUNDERSTORM WILL AFFECT SOUTH CENTRAL LEWIS AND CLARK
COUNTY...

AT 357 PM MDT...A STRONG THUNDERSTORM WAS 14 MILES NORTHWEST OF
HELENA WEST SIDE...OR 18 MILES WEST OF HELENA...MOVING EAST AT 20
MPH.

WINDS IN EXCESS OF 30 MPH AND DIME SIZE HAIL ARE POSSIBLE WITH THIS
STORM.

LOCATIONS IMPACTED INCLUDE...
HELENA VALLEY NORTHWEST...HELENA VALLEY WEST CENTRAL...HELENA WEST
SIDE...HELENA VALLEY NORTHEAST...MARYSVILLE AND CANYON CREEK.

AT THIS TIME...THE STORM SHOULD REMAIN NORTH OF DOWNTOWN HELENA.

THIS INCLUDES INTERSTATE 15 BETWEEN MILE MARKERS 195 AND 197.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

LAT...LON 4688 11212 4663 11199 4659 11230 4666 11233
      4666 11241 4670 11242 4670 11251 4674 11253
TIME...MOT...LOC 2157Z 251DEG 17KT 4669 11239

COULSTON

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
421 PM MDT TUE JUN 9 2015

MTZ012-014-053-054-092245-
CENTRAL AND SOUTHERN LEWIS AND CLARK-MEAGHER-BROADWATER-CASCADE-
421 PM MDT TUE JUN 9 2015

...A STRONG THUNDERSTORM WILL AFFECT NORTH CENTRAL BROADWATER...
NORTHWESTERN MEAGHER...SOUTHEASTERN LEWIS AND CLARK AND SOUTHWESTERN
CASCADE COUNTIES...

AT 420 PM MDT...A STRONG THUNDERSTORM WAS 9 MILES NORTHEAST OF HELENA
VALLEY NORTHEAST...OR 17 MILES NORTHEAST OF HELENA...MOVING EAST AT
30 MPH.

HAIL UP TO ONE-HALF INCH...BRIEF HEAVY RAIN AND GUSTY WINDS TO 30
MPH ARE LIKELY WITH THIS STORM.

THIS STORM WILL REMAIN OVER MAINLY RURAL AREAS OF EAST CENTRAL
CENTRAL AND SOUTHERN LEWIS AND CLARK...NORTHWESTERN MEAGHER...NORTH
CENTRAL BROADWATER AND SOUTHWESTERN CASCADE COUNTIES.

LAT...LON 4668 11184 4685 11190 4698 11136 4672 11128
TIME...MOT...LOC 2220Z 257DEG 26KT 4679 11177