Tornado in Montana, July 8, 2003

NORTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
150 PM MDT TUE JUL 08 2003

.SHORT TERM...TONIGHT THROUGH THURSDAY...
ACTIVE WEATHER EXPECTED DURING THE NEXT 8-12 HOURS...AND THEN THE
ATMOSPHERE SHOULD QUIET DOWN FOR THE REMAINDER OF THE SHORT TERM.
SPC SWODY1 MAINTAINS ALL OF THE CWA IN A SLIGHT RISK. SEVERE
THUNDERSTORM WATCH #681 IS IN EFFECT FOR THE WESTERN FOUR COUNTIES
OF OUR CWA THROUGH 00Z...AND EARLIER CONFERENCE CALL WITH SPC
INDICATES THE POTENTIAL THAT A TORNADO WATCH MAY NEED TO BE ISSUED
FOR AT LEAST PORTION OF OUR EASTERN ZONES LATER THIS AFTERNOON.
CONVECTION FIRED UP THIS MORNING ACROSS OUR WESTERN ZONES AND THIS
CONVECTION MAY HELP TO KEEP US CAPPED AND ELIMINATE THE SEVERE
THREAT TO SOME DEGREE LATE THIS AFTERNOON AND EVENING. SPECIAL 18Z
SOUNDING SHOWS A RATHER LARGE CAP AT ABOUT 800H. HOWEVER...DEW
POINTS CLIMBING INTO THE L/M 50S...VERY STRONG DYNAMICS...AND
SFC-6KM SHEAR OF 40-50 KTS INDICATE THAT THE POTENTIAL EXISTS FOR
SUPERCELLS TO DEVELOP THIS AFTERNOON AND EVENING. MAIN THREATS ARE
DAMAGING WINDS AND LARGE HAIL...BUT CANT RULE AN ISOLATED TORNADO.
A COUPLE OF SHORT WAVES TO AFFECT THE CWA THROUGH TONIGHT. MODELS
DIFFER ON EXACT PLACEMENT AND SPEED OF SHORT WAVES TO MOVE THOUGH.
MODELS DO AGREE ON TAKING ONE SHORT WAVE WELL TO OUR SOUTH THIS
EVENING ACROSS NORTHERN WY. MODELS DIFFER ON PLACEMENT OF THE SECOND
SHORTWAVE. THE ETA DRIVES THIS WAVE ACROSS SOUTHERN SECTIONS OF THE
CWA...WHILE AT THE SAME TIME THE AVN TAKES THIS WAVE ACROSS OUR
NORTHWEST ZONES AND INTO SOUTHERN SK...WITH AN ELONGATED AREA OF
VORTICITY TO SWING WEST TO EAST THROUGH THE AREA.  IN EITHER
CASE...DRIER AIR BEGINS TO FILTER IN FROM WEST TO EAST OVERNIGHT AND
WILL END PRECIPITATION ACROSS OUR WESTERN ZONES BY AROUND 06Z.  PLAN
ON CANCELING THE LAKE WIND ADVISORY WITH THE ISSUANCE OF THE NEW
PACKAGE.  WINDS OUTSIDE OF THUNDERSTORMS HAVE DIMINISHED
CONSIDERABLY DURING THE LAST FEW HOURS...AND VAD WIND PROFILE
INDICATES THAT WINDS JUST OFF THE SFC HAVE DIMINISHED T0 20 KTS FROM
35-40 KTS EARLIER THIS MORNING.

STILL LOOKS LIKE THE LAST OF ANY PRECIPITATION SHOULD END BY 12Z
TUESDAY...HOWEVER THE GFS WITH ITS FURTHER NORTH PLACEMENT OF THE
SECOND SHORT WAVE LINGERS SOME PRECIP ACROSS OUR NORTHEAST CORNER OF
THE CWA THROUGH MID-LATE MORNING. AFTER COORDINATION WITH KBIS WILL
KEEP IT DRY FOR NOW...BUT WOULD NOT BE SURPRISED IF SHOWERS LINGER
FOR AN HOUR OR TWO PAST 12Z IN SHERIDAN AND EASTERN ROOSEVELT
COUNTIES.  WEST FLOW ALOFT AND NORTHWEST FLOW AT THE SFC FOR THE
REMAINDER OF THE DAY WEDNESDAY. GFS DOES BRING A SHORT WAVE THROUGH
SOUTHERN SK...BUT LOOKS TO FAR NORTH TO TOUCH OFF ANY SHOWERS. LAPSE
RATES LOOK FAVORABLE FOR MIXING AND WITH 20KT WINDS PROGGED AT 850H
AND 25-30KT WINDS AT 700H EXPECT A BREEZY DAY WITH SFC WINDS OF 15
TO 25 MPH.  WINDS SHOULD REMAIN BELOW LAKE WIND ADVISORY
CRITERIA...BUT WILL NEED TO MONITOR CLOSELY AS WE ARE NOW IN THE
PEAK BOATING SEASON.

PACIFIC SFC HIGH BUILDS INTO THE STATE WEDNESDAY NIGHT AND THURSDAY
AND OUR UPPER FLOW VEERS INTO THE NORTHWEST IN RESPONSE TO THE RIDGE
BUILDING NORTH OUT OF THE SOUTHWEST CONUS.  TEMPERATURES SHOULD
AVERAGE CLOSE TO OR SLIGHTLY BELOW AVERAGE WITH MAINLY CLEAR SKIES
AND LIGHTER WINDS. CB

.LONG TERM...THURS NIGHT THRU TUES
STRONG UPPER RIDGE EXPECTED TO DEVELOP OVER FOUR CORNERS REGION WITH
AXIS EXTENDING NORTHWARD THROUGH CENTRAL MONTANA THURSDAY NIGHT
THROUGH AT LEAST SUNDAY. RIDGE EXPECTED TO DAMP ANY SHORTWAVES
APPROACHING FROM SOUTHWEST OR NORTHWEST...HENCE WILL CONTINUE DRY
AND VERY WARM TO HOT FORECAST. HAVE BOOSTED MAXIMA SLIGHTLY FOR THIS
PERIOD FROM INHERITED FORECAST...AND SUSPECT MAY TREND HIGHER THAN
THIS BUT RELUCTANT TO GET TOO FAR AHEAD OF EVENTS. GFS SUGGESTS
RIDGE FLATTENS EARLY IN FOLLOWING WEEK WHICH IS LIKELY TO ALLOW
TEMPERATURES TO BACK OFF AND INCREASE ODDS OF POPS. HOWEVER...LACK
CONFIDENCE TO INTRODUCE POPS AT THIS TIME GIVEN SLIM INDICATIONS AND
CURRENT DRY TREND. ASIDE FROM INCREASING MAXIMA TO BETTER MATCH
ADJACENT OFFICES...FEW CHANGES TO GOING FORECAST.  DNS

KGGW UUB 054/081 053/083 055/087 92600000
     BUTE 057/089 057/090 055/085 055/082 8600000330
KGDV BUB 058/084 052/084 054/088 92700000
     BUTE 059/089 057/093 057/089 057/084 8600000330

.GGW...SEVERE THUNDERSTORM WATCH #681 IS IN EFFECT UNTIL 00Z WED FOR
PHILLIPS...PETROLEUM...VALLEY AND GARFIELD COUNTIES.

MTZ016>027-059>062-091200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GLASGOW MT
204 PM MDT TUE JUL 8 2003

.DAY ONE...

A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED FOR
PHILLIPS...PETROLEUM...VALLEY AND GARFIELD COUNTIES THROUGH 6 PM.
THUNDERSTORMS HAVE DEVELOPED ACROSS CENTRAL MONTANA THIS
AFTERNOON...AND WILL MOVE EAST LATER TODAY. SOME OF THESE STORMS
WILL BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS. AN ISOLATED
TORNADO IS ALSO POSSIBLE LATER THIS AFTERNOON IN THE EAST. PLEASE
REFER TO GTFSEL1 OR WWUS20 KWNS FOR ADDITIONAL INFORMATION.

.DAYS TWO THROUGH SEVEN...

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.

BOGEL