

588 

WWUS20 KWNS 200009

SEL4

SPC WW 200009

IAZ000-MNZ000-NEZ000-SDZ000-200700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 414

NWS STORM PREDICTION CENTER NORMAN OK

705 PM CDT TUE JUN 19 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHWEST IOWA

       SOUTHWEST MINNESOTA

       CENTRAL AND NORTHEAST NEBRASKA

       SOUTHEAST SOUTH DAKOTA



EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 705 PM

UNTIL 200 AM CDT.



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 APPROXIMATELY ALONG AND 75

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 35 MILES SOUTH

SOUTHWEST OF VALENTINE NEBRASKA TO 20 MILES EAST OF WORTHINGTON

MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY

DO PRODUCE TORNADOES.



OTHER WATCH INFORMATION...CONTINUE...WW 412...WW 413...



DISCUSSION...ISOLATED STORMS HAVE INITIATED ALONG A COLD FRONT

SITUATED NE TO SW ACROSS NCNTRL NEB THIS EVENING. DESPITE WARM

ELEVATED MIXED LAYER ALOFT...THE COMBINATION OF DEEP BOUNDARY LAYER

HEATING AND MIXING AND FOCUSED LOW LEVEL CONVERGENCE ALONG THE FRONT

SHOULD CONTINUE TO SUPPORT TSTM INITIATION WITHIN A VERY UNSTABLE

AIR MASS ACROSS THE REGION. SHORT-TERM STORM-SCALE GUIDANCE SUGGESTS

THAT STORM COVERAGE SHOULD INCREASE ALONG AND IMMEDIATELY NORTH OF

THE FRONTAL BOUNDARY OVER THE NEXT FEW HOURS WITH GREATER

CONCENTRATION OF STORMS FROM NERN NEB INTO SD AND ADJACENT AREAS OF

NW IA AND SW MN. MODEST SHEAR ACROSS THESE AREAS...STRONGER ON THE

COOL SIDE OF THE FRONT...WILL SUPPORT UPDRAFT PERSISTENCE AND

ROTATION WITH A FEW HAIL/WIND EVENT LIKELY FROM A THE STRONGER

CORES. WITH TIME AND GREATER STORM COVERAGE...DAMAGING WIND

POTENTIAL MAY INCREASE AS A SMALL FORWARD PROPAGATING MCS DEVELOPS

ACROSS SERN SD INTO MN/NW IA. FARTHER SW ALONG THE BOUNDARY...MORE

ISOLATED STORMS WILL POSE DOWNBURST WIND AND HAIL THREATS. EVENING

RAOB FROM LBF IS CHARACTERISTIC OF DOWNBURST ENVIRONMENT AND ALSO

PRODUCES 1.75 INCH HAIL FROM THE SPC ANALOG SOUNDING HAIL MODEL.



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 25020.





...CARBIN



588 

WWUS20 KWNS 200009

SEL4

SPC WW 200009

IAZ000-MNZ000-NEZ000-SDZ000-200700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 414

NWS STORM PREDICTION CENTER NORMAN OK

705 PM CDT TUE JUN 19 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHWEST IOWA

       SOUTHWEST MINNESOTA

       CENTRAL AND NORTHEAST NEBRASKA

       SOUTHEAST SOUTH DAKOTA



EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 705 PM

UNTIL 200 AM CDT.



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 APPROXIMATELY ALONG AND 75

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 35 MILES SOUTH

SOUTHWEST OF VALENTINE NEBRASKA TO 20 MILES EAST OF WORTHINGTON

MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY

DO PRODUCE TORNADOES.



OTHER WATCH INFORMATION...CONTINUE...WW 412...WW 413...



DISCUSSION...ISOLATED STORMS HAVE INITIATED ALONG A COLD FRONT

SITUATED NE TO SW ACROSS NCNTRL NEB THIS EVENING. DESPITE WARM

ELEVATED MIXED LAYER ALOFT...THE COMBINATION OF DEEP BOUNDARY LAYER

HEATING AND MIXING AND FOCUSED LOW LEVEL CONVERGENCE ALONG THE FRONT

SHOULD CONTINUE TO SUPPORT TSTM INITIATION WITHIN A VERY UNSTABLE

AIR MASS ACROSS THE REGION. SHORT-TERM STORM-SCALE GUIDANCE SUGGESTS

THAT STORM COVERAGE SHOULD INCREASE ALONG AND IMMEDIATELY NORTH OF

THE FRONTAL BOUNDARY OVER THE NEXT FEW HOURS WITH GREATER

CONCENTRATION OF STORMS FROM NERN NEB INTO SD AND ADJACENT AREAS OF

NW IA AND SW MN. MODEST SHEAR ACROSS THESE AREAS...STRONGER ON THE

COOL SIDE OF THE FRONT...WILL SUPPORT UPDRAFT PERSISTENCE AND

ROTATION WITH A FEW HAIL/WIND EVENT LIKELY FROM A THE STRONGER

CORES. WITH TIME AND GREATER STORM COVERAGE...DAMAGING WIND

POTENTIAL MAY INCREASE AS A SMALL FORWARD PROPAGATING MCS DEVELOPS

ACROSS SERN SD INTO MN/NW IA. FARTHER SW ALONG THE BOUNDARY...MORE

ISOLATED STORMS WILL POSE DOWNBURST WIND AND HAIL THREATS. EVENING

RAOB FROM LBF IS CHARACTERISTIC OF DOWNBURST ENVIRONMENT AND ALSO

PRODUCES 1.75 INCH HAIL FROM THE SPC ANALOG SOUNDING HAIL MODEL.



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 25020.





...CARBIN

