Damaging Wind in Montana, June 30, 2003

NORTHEAST MONTANA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GLASGOW MT
315 PM MDT MON JUN 30 2003

.SHORT TERM...TONIGHT THRU THU...
HOT DRY AIRMASS ASSOCIATED WITH STRONG UPPER RIDGE...AND LONG S-SE
FETCH AT LOWER LEVELS OVER NE MT GIVING HIGHS IN THE 90S TODAY.
SURFACE GRADIENTS GIVING 15-25 MPH S-SE WINDS WHICH HAS ADVECTED
SOME MOISTURE AIR N ALONG HIGH PLAINS TO NE MT...RESULTING IN DEW
POINTS IN 50S.

CONVECTION JUST BEGINNING TO OUR SW. DRY AIRMASS EXTENSIVE OVER
WESTERN STATES AND EASTERN PACIFIC. NO HOPE FOR BILL MOISTURE IN
THIS PATTERN EITHER. MODELS CONTINUE TO INDICATE SUBSIDENCE CAP TO
BE ERASED TONIGHT. EXPECT THERE WILL BE SOME STRONG TO SEVERE
NOCTURNAL CONVECTION TONIGHT...BUT GENERALLY ISOLATED. LIFTED
INDEXES TO -5...CAPES TO 1800 J/KG...MOST FAVORABLE IN OUR EAST
AFTER MIDNIGHT. SHEAR SO-SO. DYNAMICS NOT GREAT EITHER BUT WILL
INCREASE WITH SHORTWAVE ASSOCIATED WITH STEADILY WEAKENING COLD
FRONT MOVING ACROSS AREA. SPC SLIGHT RISK CONTINUES. WITH HIGH BASED
THUNDERSTORMS...EXPECT DOWNBURST DAMAGING WINDS TO BE PRIMARY THREAT
PER SWODY1 AND WILL CONTINUE WITH THAT EMPHASIS IN
ZONES...HWO...SPS. GOING FAIRLY LIGHT WITH RAINFALL AMOUNTS IN GRIDS.

PATTERN QUITE FAMILIAR THIS TIME OF YEAR WITH PEAK SEVERE
THUNDERSTORM SEASON. CLOSED UPPER LOW STALLS ALONG BC COAST PUTTING
MT INTO A SW FLOW ALOFT FOR A FEW DAYS. MAIN DIFFERENCE OVER MOST
YEARS IS AIRMASS DRIER THAN NORMAL. 500 MB HEIGHTS SLOWLY LOWERING
THROUGH PERIOD...WITH SLOW COOLING TREND. AT LEAST A COUPLE OF WEAK
SHORTWAVES TO MOVE THROUGH TUE AND WED. EXPECT THIS WILL GENERATE
SOME ISOLATED CONVECTION BUT MAY BE QUITE ISOLATED...MOST IN AREAS
WHERE AIRMASS IS MORE MOIST AND UNSTABLE. OVERALL THOUGH...KEEPING
POPS A LITTLE LOWER THAN NORMALLY EXPECTED IN THIS PATTERN. UPPER
LOW MOVES NE ACROSS CANADA BY THU DRAGGING AN UPPER TROUGH ACROSS
NORTHERN ZONES. AIRMASS GROWS DRIER THOUGH IN INCREASING DOWNSLOPE
FLOW KEEPING POPS ISOLATED AND CONFINED TO NORTH BORDER ZONES.
SIMONSEN

.LONG TERM...THURSDAY NIGHT THROUGH MONDAY...
A WELCOMED BROAD UPPER TROF WILL DOMINATE THE WEATHER DURING THE
BEGINNING OF THIS PERIOD. THIS WILL BRING A COOL/DRY AIRMASS TO THE
AREA AT ALL LEVELS TO WORK INTO THE AREA THURSDAY NIGHT. THE TROF
BROADENS OVER CANADA DURING MUCH OF THE PERIOD WITH MUCH OF THE
MOISTURE AND INSTABILITY REMAINING TO OUR NORTH. TEMPERATURES LOOK
TO REMAIN BELOW NORMAL FOR MUCH OF THE PERIOD. HAVE NOT MADE TOO
MANY CHANGES TO GOING FORECAST.  JAMBA

KGGW BBB 060/086 058/083 054/079 82300020
     EEBB 051/079 056/080 056/081 056/081 7600000000

KGDV BBB 062/091 060/087 055/082 82322020
     EBBB 053/079 057/084 057/084 057/084 7600000000

.GGW...NONE.

MTZ016>027-059>062-011200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GLASGOW MT
1020 AM MDT MON JUN 30 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST MONTANA

.DAY ONE...
AN APPROACHING COLD FRONT FROM THE WEST WILL ENTER A WARM AND
UNSTABLE AIRMASS OVER NORTHEAST MONTANA THIS EVENING AND TONIGHT.
MOISTURE WILL BE LIMITED...SO THUNDERSTORMS THAT FORM WILL BE
ISOLATED TO SCATTERED...BUT THOSE THAT DO FORM WILL BE VERY STRONG
TO SEVERE. DAMAGING WINDS ARE POSSIBLE FROM THESE. THE THREAT OF
SEVERE THUNDERSTORM WINDS WILL BEGIN IN WESTERN SECTIONS OF
NORTHEAST MONTANA EARLY THIS EVENING...SPREADING TO EASTERN SECTIONS
AND THE NORTH DAKOTA BORDER AROUND MIDNIGHT.

.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.

SIMONSEN