Severe Thunderstorm Warning 46, NWS Bismarck, ND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
320 PM CDT SUN JUN 20 1999

SCATTERED SHOWERS/TSTMS OVER NRN HALF OF ND ATTM...AND STRONG/SVR
TSTMS IN NERN MT. MODELS HAVE VORT IN ERN MT AT 18Z PROGGED TO THE
ND/MT BORDER BY 00Z...THEN ETA HAS MORE REALISTIC PLACING OF VORT
OVER CNTRL ND BY 06Z TON. THINK THIS WL BE THE BEST FOCUS/TIMING OF
TSTMS. LIS WELL BELOW ZERO. CAPE THIS AM AT BIS WAS 2000...AND ETA
KEEPS CAPES WELL ABOVE 1500 THROUGH 48 HOURS. HERE AT BIS THE
CONVECTIVE TEMP IS IN THE MID 80S...BUT WITH H5 SHORTWAVE KICKER...
TSTMS SHOULD HAVE NO PROBLEM FIRING OFF. DEWPOINTS WELL INTO THE 60S
THIS AFTN. K INDEX WAS 33 THIS AM WITH PW OF 1.32. LARGE HAIL AND
HEAVY RAIN THE BIGGEST THREAT. HODOGRAPH NOT IMPRESSIVE FOR TORNADIC
ACTIVITY. ANTICIPATING WEATHER WATCH FOR WRN COUNTIES EITHER NOW OR
IN EARLY EVE HOURS...WITH POSSIBLE ADDITIONAL WATCHES CNTRL ND LATER.

FOR MON...H7 TEMPS BUILD UP AND FORM A CAP OVER WRN ND BY 18Z.
ANOTHER SHORTWAVE MOVING IN FROM WY SHOULD BREAK CAP BY LATE
AFTN/EARLY EVE. WL KEEP MENTION OF TSTMS UNTIL LATE AFTN IN THE
WEST...AND FOR MON NIGHT REST OF CWA. LOOKS LIKE ANOTHER DAY OF
SEVERE WEATHER MON NIGHT. SFC TROUGH/COLD FRONT FINALLY MOVES
THROUGH STA MON NIGHT AND TUE WITH A FEW H5 SHORTWAVES TO KEEP
SHOWERS/TSTMS IN THE FCST THROUGH TUE. GOOD NWLY WINDS BEHIND FRONT
TO BRING WINDY DAY TUE WITH COOLER TEMPS.

IN THE LONGER TERM...WED LOOKS LIKE A DRY DAY...BUT THU...AND ESP
FRI NIGHT LOOKING GOOD FOR PCPN.

.BIS...NONE.
JV

NDZ001>053-210500-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 456
STORM PREDICTION CENTER NORMAN OK
339 PM MDT SUN JUN 20 1999

THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

   EASTERN MONTANA
   WESTERN NORTH DAKOTA

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 415 PM UNTIL 1100
PM MDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 75 STATUTE MILES
EAST AND WEST OF A LINE FROM 60 MILES WEST SOUTHWEST OF BROADUS
MONTANA TO 30 MILES NORTH NORTHWEST OF WILLISTON NORTH DAKOTA.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA.
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

DISCUSSION...WEAK CONVERGENCE SUFFICIENT TO INITIATE THUNDERSTORMS
IN THE VERY UNSTABLE AIRMASS AVAILABLE ACROSS ERN MT. WITH CAPES
AOA 4000 J/KG AND MARGINAL SHEAR...PRIMARY THREAT WILL BE LARGE
HAIL.  STORMS WILL INCREASE IN COVERAGE DURING THE EVENING AND
SLOWLY SPREAD EWD INTO WRN ND.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550.  MEAN STORM
MOTION VECTOR 27025.

...HALES

450,1080 483,1053 483,1021 450,1050

NDZ001>053-210500-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 456
STORM PREDICTION CENTER NORMAN OK
339 PM MDT SUN JUN 20 1999

THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

   EASTERN MONTANA
   WESTERN NORTH DAKOTA

EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 415 PM UNTIL 1100
PM MDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 75 STATUTE MILES
EAST AND WEST OF A LINE FROM 60 MILES WEST SOUTHWEST OF BROADUS
MONTANA TO 30 MILES NORTH NORTHWEST OF WILLISTON NORTH DAKOTA.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA.
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.

DISCUSSION...WEAK CONVERGENCE SUFFICIENT TO INITIATE THUNDERSTORMS
IN THE VERY UNSTABLE AIRMASS AVAILABLE ACROSS ERN MT. WITH CAPES
AOA 4000 J/KG AND MARGINAL SHEAR...PRIMARY THREAT WILL BE LARGE
HAIL.  STORMS WILL INCREASE IN COVERAGE DURING THE EVENING AND
SLOWLY SPREAD EWD INTO WRN ND.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550.  MEAN STORM
MOTION VECTOR 27025.

...HALES

450,1080 483,1053 483,1021 450,1050