Hail and Damaging Winds in Montana, June 13 to 14, 2013

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
846 PM MDT THU JUN 13 2013

.SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SATURDAY...

AS OF 830 PM SHOWERS AND THUNDERSTORMS ARE BEGINNING TO DEVELOP
ON A SURFACE TROUGH ORIENTED NORTH/SOUTH THROUGH EASTERN GARFIELD
AND CENTRAL VALLEY COUNTY. SREF MEMBERS APPEAR TO TAKE MOST OF
THE DEVELOPING CELLS AND MOVE THEM SLOWLY TOWARD THE NORTHEAST
OVERNIGHT. CELLS LOCATED OR DEVELOPING OVER ROSEBUD AND CUSTER
COUNTY ARE ALSO ANTICIPATED TO MOVE UP THE YELLOWSTONE PORTION OF
THE CWA LATER TONIGHT BUT MAY TAKE UNTIL NEAR OR AFTER MIDNIGHT
BEFORE THESE AREAS ARE IMPACTED. GAH

PREVIOUS SHORT TERM DISCUSSION...
A VIGOROUS UPPER LEVEL TROUGH OVER THE PACIFIC NORTHWEST
CONTINUES TO PUSH EASTWARD TOWARD EASTERN MONTANA. DISTURBANCES IN
THE SOUTHWEST FLOW ALOFT AHEAD OF THE TROUGH IS COMBINING WITH
AMPLE MOISTURE IN A SOUTHEAST SURFACE FLOW TO TRIGGER ISOLATED
THUNDERSTORMS. EXPECT A STRONGER DISTURBANCE TO PUSH THROUGH A BIT
LATER ON THIS AFTERNOON/EVENING...BRINGING MORE WIDESPREAD SHOWERS
AND THUNDERSTORMS TO MUCH OF NORTHEAST MONTANA. WITH GOOD MOISTURE
AND FAVORABLE SHEAR PROFILES SOME STORMS MAY BE SEVERE WITH LARGE
HAIL AND DAMAGING WINDS BEING THE MAIN THREATS. A SEVERE
THUNDERSTORM WATCH IS IN EFFECT. WITH AMPLE MOISTURE AVAILABLE
STORMS WILL LIKELY PRODUCE HEAVY RAINFALL WHICH COULD LEAD TO
FLASH FLOODING OF CREEKS AND STREAMS. A FLASH FLOOD WATCH IS IN
EFFECT THROUGH THE OVERNIGHT HOURS AS WELL.

FRIDAY THE UPPER TROUGH WILL STRENGTHEN AS A VERTICALLY STACKED
LOW SPINS UP OVER CENTRAL SASKATCHEWAN. SHOWER ACTIVITY WILL
TAPER FROM SOUTH TO NORTH OVER NORTHEAST MONTANA THROUGH THE DAY.
PRECIPITATION AMOUNTS WILL BE ON THE DECREASE...THUS THE THREAT
FOR FLASH FLOODING WILL END BY EARLY MORNING. WESTERLY WINDS WILL
PICK UP BY THE AFTERNOON AND A LAKE WIND ADVISORY LOOKS LIKE A
POSSIBILITY.

FRIDAY NIGHT INTO SATURDAY WESTERLY FLOW ALOFT WILL DOMINATE WITH
THE UPPER LOW TO THE NORTH. FRIDAY EVENING WILL SEE SOME CONTINUED
LOW CHANCES FOR PRECIPITATION ALONG THE CANADIAN BORDER...BUT DRY
CONDITIONS WILL RULE LATE FRIDAY NIGHT INTO SATURDAY AS THE UPPER
LOW WRAPS UP OVER CENTRAL SASK. GILCHRIST

.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
THE LATEST GFS PLACES A COMPACT STACKED LOW OVER SOUTHERN
SASKATCHEWAN AT 00Z SUNDAY. THIS LOW WILL DROP SOUTHEAST INTO THE
NORTH DAKOTA BY SUNDAY NIGHT. THIS WILL PLACE NORTHWEST FLOW ALOFT
OVER NEMONT TO REINFORCE THE NORTHWEST SURFACE WIND FOR THE
WEEKEND. ANY SHOWERS WILL LIKELY BE CONFINED TO THE NORTHERN TIER.

AN UPPER RIDGE MOVES OVER THE DIVIDE SUNDAY NIGHT TO BRING A DRIER
AND WARMER PERIOD TO THE LOCAL REGION THROUGH WEDNESDAY. THEN
ANOTHER POTENT STORM SYSTEM ADVANCES ACROSS THE PAC-NW...SENDING A
COLD FRONT ACROSS NEMONT WEDNESDAY NIGHT. THIS WILL INTRODUCE
ANOTHER PERIOD OF UNSETTLED WEATHER. MODELS DIFFER ON DETAILS NOW
BUT THERE IS THE POTENTIAL FOR STRONG CONVECTIVE ACTIVITY ALONG
WITH LOCALIZED HEAVY RAIN. NO CHANGES WERE MADE TO THE EXTENDED
GRIDS. SCT

PREVIOUS DISCUSSION...
THE EXTENDED BEGINS WITH AN UPPER LOW OVER MANITOBA AND RIDGING
OVER THE ROCKIES SATURDAY NIGHT. THIS WILL BE BRIEF...AS ANOTHER
UPPER LOW DROPS INTO THE PACIFIC NORTHWEST THIS WEEKEND. THE
MODELS ARE TRENDING FURTHER WEST WITH THE UPPER LOW OVER THE
WEEKEND AND EARLY NEXT WEEK. THIS SHOULD KEEP NORTHEAST MONTANA
UNDER A RIDGE. TRENDED THE FORECAST DRIER...AND A TAD WARMER
HOWEVER MIGHT NOT BE WARM ENOUGH.

THEN THE UPPER LOW SHIFTS EARLY NEXT WEEK EASTWARD WHICH WILL
BRING ANOTHER ROUND OF THE THUNDERSTORMS TO THE NORTHERN ROCKIES
FOR MID WEEK.

MODEL TRENDS SUPPORT THE IDEA OF WARMER AND DRIER UNTIL MID NEXT
WEEK. PROTON

&&

.AVIATION...
MOSTLY VFR. IFR FROM THUNDERSTORMS POSSIBLE.

A STRONG COLD FRONT MOVING INTO THE AREA LATE THIS EVENING WILL
PRODUCE THUNDERSTORMS...SOME POSSIBLY SEVERE WITH LARGE HAIL AND
WINDS IN EXCESS OF 50KTS. HEAVY RAIN COULD BE ASSOCIATED WITH ANY
THUNDERSTORM. MOST STORMS SHOULD EXIT THE AREA AROUND 6 AM FRIDAY
MORNING. EXPECT MAINLY VFR WITH BRIEF PERIODS OF MVFR/IFR
CEILINGS AND VISIBILITY FROM PASSING CELLS.

LIGHT WINDS OVERNIGHT WILL SWITCH TO THE WEST AS THE COLD FRONT
PASSES AND GAIN SPEED TO 10 TO 20 KTS BY THE AFTERNOON HOURS. GAH

&&

.GLASGOW WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 6 AM MDT FRIDAY FOR CENTRAL AND
SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...GARFIELD...
MCCONE...NORTHERN PHILLIPS...NORTHERN VALLEY...PETROLEUM...
PRAIRIE...SOUTHWEST PHILLIPS.

&&

WEATHER.GOV/GLASGOW

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE GLASGOW MT
451 PM MDT THU JUN 13 2013

MTZ018>020-024-025-027-062-140900-
DANIELS-SHERIDAN-WESTERN ROOSEVELT-RICHLAND-DAWSON-WIBAUX-
EASTERN ROOSEVELT-
451 PM MDT THU JUN 13 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST
MONTANA.

.DAY ONE...TONIGHT

AN UPPER LEVEL SYSTEM WILL LEAD TO THE DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS THIS AFTERNOON...WHICH WILL LINGER INTO TONIGHT.
SOME STORMS MAY BECOME SEVERE CAPABLE OF PRODUCING LARGE HAIL AND
DAMAGING WINDS. LOCALLY HEAVY RAINFALL IS POSSIBLE WHICH MAY LEAD
TO FLOODING OF RIVERS AND STREAMS AS WELL AS LOW LYING AND POOR
DRAINAGE AREAS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

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

MTZ016-017-021>023-026-059>061-140900-
CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY-
PETROLEUM-GARFIELD-MCCONE-PRAIRIE-NORTHERN PHILLIPS-
SOUTHWEST PHILLIPS-NORTHERN VALLEY-
451 PM MDT THU JUN 13 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST
MONTANA.

.DAY ONE...TONIGHT

STRONG TO SEVERE THUNDERSTORMS CAN BE EXPECTED THIS AFTERNOON AND
OVERNIGHT. HEAVY RAINFALL CAN BE EXPECTED WITH STORMS...ALONG
WITH LARGE HAIL AND DAMAGING WINDS. A FLASH FLOOD WATCH IS IN
EFFECT THROUGH 6 AM FRIDAY MORNING. A SEVERE THUNDERSTORM WATCH IS
IN EFFECT THROUGH 9 PM TONIGHT.

AN AREAL FLOOD ADVISORY REMAINS IN EFFECT FOR UPPER PORTIONS OF
BEAVER CREEK IN SOUTHERN PHILLIPS COUNTY.

FLOOD WARNINGS REMAIN IN EFFECT FOR PARTS OF THE MILK RIVER
INCLUDING AREAS NEAR TAMPICO...AND GLASGOW.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

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