

550 

WWUS20 KWNS 211017

SEL1

SPC WW 211017

IAZ000-MNZ000-WIZ000-211700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 471

NWS STORM PREDICTION CENTER NORMAN OK

515 AM CDT THU AUG 21 2014



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  NORTHERN IOWA

  SOUTHEAST MINNESOTA

  SOUTHWEST WISCONSIN



* EFFECTIVE THIS THURSDAY MORNING FROM 515 AM UNTIL NOON CDT.



* PRIMARY THREATS INCLUDE...

  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

  ISOLATED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 40

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

NORTHWEST OF MASON CITY IOWA TO 50 MILES SOUTHEAST OF LA CROSSE

WISCONSIN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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 470...



DISCUSSION...A MODERATELY STRONG LOW-LEVEL JET/WARM ADVECTION AND AN

UPSTREAM MESOSCALE CONVECTIVE VORTEX WILL INFLUENCE STORM

DEVELOPMENT/PERSISTENCE THROUGH THE EARLY/MID-MORNING HOURS ACROSS

THE REGION. THIS INCLUDES THE POTENTIAL FOR SEMI-DISCRETE STORMS TO

PRODUCE SEVERE HAIL...WHILE A QUASI-LINEAR CLUSTER OF STORMS

OTHERWISE CONTINUES TO ORGANIZE/STEADILY PROGRESS EASTWARD WITH

LOCALLY DAMAGING WINDS POSSIBLE. IN ASSOCIATION WITH THIS CONVECTIVE

LINE...A 55 KT WIND GUST WAS MEASURED EARLIER /438 AM CDT/ IN

ESTERVILLE IA.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 27040.





...GUYER



793 

WWUS20 KWNS 211017

SEL1

SPC WW 211017

IAZ000-MNZ000-WIZ000-211700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 471

NWS STORM PREDICTION CENTER NORMAN OK

515 AM CDT THU AUG 21 2014



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  NORTHERN IOWA

  SOUTHEAST MINNESOTA

  SOUTHWEST WISCONSIN



* EFFECTIVE THIS THURSDAY MORNING FROM 515 AM UNTIL NOON CDT.



* PRIMARY THREATS INCLUDE...

  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

  ISOLATED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 40

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

NORTHWEST OF MASON CITY IOWA TO 50 MILES SOUTHEAST OF LA CROSSE

WISCONSIN.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



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 470...



DISCUSSION...A MODERATELY STRONG LOW-LEVEL JET/WARM ADVECTION AND AN

UPSTREAM MESOSCALE CONVECTIVE VORTEX WILL INFLUENCE STORM

DEVELOPMENT/PERSISTENCE THROUGH THE EARLY/MID-MORNING HOURS ACROSS

THE REGION. THIS INCLUDES THE POTENTIAL FOR SEMI-DISCRETE STORMS TO

PRODUCE SEVERE HAIL...WHILE A QUASI-LINEAR CLUSTER OF STORMS

OTHERWISE CONTINUES TO ORGANIZE/STEADILY PROGRESS EASTWARD WITH

LOCALLY DAMAGING WINDS POSSIBLE. IN ASSOCIATION WITH THIS CONVECTIVE

LINE...A 55 KT WIND GUST WAS MEASURED EARLIER /438 AM CDT/ IN

ESTERVILLE IA.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 27040.





...GUYER

