

530 

WWUS20 KWNS 071913

SEL0

SPC WW 071913

IAZ000-MNZ000-NEZ000-SDZ000-080300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 560

NWS STORM PREDICTION CENTER NORMAN OK

215 PM CDT TUE JUL 7 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHEAST IOWA

       SOUTHWEST MINNESOTA

       NORTHEAST NEBRASKA

       EASTERN SOUTH DAKOTA



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 215 PM UNTIL

1000 PM 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 80

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 15 MILES NORTH

NORTHWEST OF CHAMBERLAIN SOUTH DAKOTA TO 20 MILES NORTHEAST OF

SPENCER IOWA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 559...



DISCUSSION...THUNDERSTORMS ARE EXPECTED TO INTENSIFY IN THE NEXT

COUPLE OF HOURS OVER EASTERN SD...SPREADING INTO PARTS OF SOUTHWEST

MN AND NORTHWEST IA DURING EVENING.  STRONG INSTABILITY...SUFFICIENT

DEEP LAYER VERTICAL SHEAR...AND PRESENCE OF SEVERAL WEAK BOUNDARIES

WILL HELP TO PROMOTE A RISK OF DAMAGING WINDS AND HAIL WITH STRONGER

CELLS THROUGH 03Z.



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 500. MEAN STORM

MOTION VECTOR 29030.





...HART

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