Special Weather Statement, NWS Great Falls, MT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
1126 AM MDT THU AUG 11 2011

UPDATED AVIATION SECTION

.UPDATE...
SHORTWAVE TROF CURRENTLY OVER WESTERN MT WILL CONTINUE TO PUSH EAST
INTO OUR AREA THIS AFTN/EVE.  LATEST RADAR IMAGERY INDICATES A BAND
OF LIGHT SHOWERS HAS DEVELOPED AHEAD OF THE TROF AXIS...FROM NORTH
OF GREAT FALLS TO AROUND BUTTE...BUT IS PRODUCING LITTLE IF ANY
PRECIPITATION.  ONLY FORECAST ADJUSTMENT WAS TO ADD IN SLIGHT CHANCE
OF SHOWERS FOR LEWIS & CLARK COUNTY AND ERN PORTIONS OF
PONDERA/TETON COUNTIES WITH THIS BAND.  REST OF GOING FORECAST IN
GOOD SHAPE.   WARANAUSKAS

.DISCUSSION...

TODAY THROUGH SATURDAY...WEAK UPPER TROF WILL MOVE ACROSS THE AREA
TODAY.THE AIRMASS REMAINS UNSTABLE AND THUNDERSTORMS WILL DEVELOP
AGAIN DURING THE AFTERNOON AND CONTINUE INTO EARLY EVENING. IT
APPEARS THE EASTERN PORTION OF THE COUNTY WARNING AREA WILL SEE
THE GREATEST THREAT FOR THUNDERSTORM ACTIVITY. THE BIGGEST THREAT
FROM THESE STORMS WILL AGAIN BE SMALL HAIL AND GUSTY WINDS.
HEIGHTS BEGIN TO RISE OVER WESTERN MONTANA LATER TONIGHT AS AN
UPPER RIDGE AMPLIFIES OVER THE WESTERN UNITED STATES AND MOVES
EAST OF THE CONTINENTAL DIVIDE FRIDAY. THIS WILL USHER IN A DRY
AND VERY WARM PERIOD. MID AND HIGH LEVEL CLOUDS WILL HELP KEEP
TEMPERATURES NEAR OR SLIGHTLY BELOW SEASONAL AVERAGES TODAY AND
FRIDAY BUT READINGS SATURDAY WILL APPROACH 90 DEGREES. EMANUEL

SATURDAY NIGHT THROUGH THURSDAY...MODELS REMAIN IN AGREEMENT WITH
DRIER CONDITIONS FOR THE FIRST HALF OF THE FORECAST PERIOD.
RIDGING WILL KEEP CHANCES OF PRECIPITATION RELATIVELY LOW UNTIL
SUNDAY AFTERNOON WHEN A SLIGHT CHANCE OF AFTERNOON SHOWERS RETURNS
TO SOUTHWEST MONTANA. BEYOND SUNDAY...MODELS STILL SOMEWHAT
DIFFER BUT DO AGREE THAT THE CHANCE OF MAINLY AFTERNOON
PRECIPITATION WILL LIKELY RETURN NEXT WEEK. TEMPERATURES WILL
CONTINUE TO REMAIN RIGHT AROUND SEASONAL AVERAGES AND WINDS LOOK
TO BE LIGHT WITH A FEW DAYS OF AFTERNOON BREEZY CONDITIONS LIKELY.

&&

.AVIATION...
UPDATED 1720Z.
AN UPPER LEVEL TROUGH OF LOW PRESSURE MOVING THROUGH THE REGION
TODAY WILL GENERATE SHOWERS AND A FEW THUNDERSTORMS THROUGH THE
EVENING HOURS. ONGOING SHOWERS AND ISOLATED THUNDERSTORMS OVER
CENTRAL MONTANA...NEAR KGTF AND KHLN...WILL MOVE EASTWARD EVENTUALLY
AFFECTING KLWT AFTER 20Z. EXPECT ANOTHER AREA OF SHOWERS AND
THUNDERSTORMS TO DEVELOP NEAR KCTB AFTER 20Z...SPREADING TO NEAR
KHVR BY 23Z. ALL THE ACTIVITY SHOULD DIMINISH AFTER 06Z FRIDAY ALONG
WITH CLEARING SKIES. EXPECT MAINLY VFR CONDITIONS THROUGH THE TAF
PERIOD BUT COULD NOT RULE OUT BRIEF MVFR CONDITIONS WITH A FEW OF
THE HEAVIER SHOWERS/STORMS DUE TO REDUCED VISIBILITY. CEILINGS WILL
BE MAINLY ABOVE 9000 FT...HOWEVER MOUNTAIN OBSCURATION WILL OCCUR
WITH HEAVIER SHOWERS/STORMS WHERE CEILINGS MAY LOWER TO 6000 FT.
LANGLIEB

&&

.PRELIMINARY POINT TEMPS/POPS...
GTF  80  49  83  53 /  20  20   0   0
CTB  76  47  80  49 /  20  20   0   0
HLN  77  51  82  52 /  10  10   0   0
BZN  77  45  81  46 /  20  20  10   0
WEY  70  33  72  33 /  20  20  10   0
DLN  75  43  78  45 /  10  10   0   0
HVR  84  51  84  54 /  40  30  10   0
LWT  76  48  78  50 /  30  20  10   0

&&

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

WEATHER.GOV/GREATFALLS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREAT FALLS MT
527 AM MDT THU AUG 11 2011

MTZ008>015-044>055-121130-
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-
527 AM MDT THU AUG 11 2011

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 IS LOW.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
117 PM MDT THU AUG 11 2011

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1250 PM     HAIL             12 ENE RINGLING         46.36N 110.60W
08/11/2011  M0.25 INCH       MEAGHER            MT   TRAINED SPOTTER

            PEA SIZED HAIL AND 45 MPH WINDS.

1250 PM     TSTM WND GST     12 ENE RINGLING         46.36N 110.60W
08/11/2011  E45 MPH          MEAGHER            MT   TRAINED SPOTTER

            PEA SIZED HAIL AND 45 MPH WINDS.

&&

JOH

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
125 PM MDT THU AUG 11 2011

MTZ047-112030-
BLAINE MT-
125 PM MDT THU AUG 11 2011

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN BLAINE COUNTY UNTIL 230
PM MDT...

AT 123 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 18 MILES WEST OF HAYS...OR 40 MILES SOUTH OF
CHINOOK...MOVING EAST AT 15 MPH.

HAIL UP TO THE SIZE OF NICKELS AND WIND GUSTS UP TO 40 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT
DANGEROUS LIGHTNING.

* LOCATIONS IMPACTED INCLUDE...
   HAYS...

LAT...LON 4797 10853 4798 10860 4792 10864 4792 10887
      4786 10887 4786 10889 4797 10934 4813 10933
      4841 10844
TIME...MOT...LOC 1925Z 272DEG 12KT 4802 10903

HOENISCH