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WWUS20 KWNS 172348

SEL5

SPC WW 172348

IAZ000-NEZ000-SDZ000-180600-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 315

NWS STORM PREDICTION CENTER NORMAN OK

650 PM CDT TUE JUN 17 2014



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* TORNADO WATCH FOR PORTIONS OF

  NORTHWEST IOWA

  NORTHEAST NEBRASKA

  SOUTHEAST SOUTH DAKOTA



* EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 650 PM

  UNTIL 100 AM CDT.



* PRIMARY THREATS INCLUDE...

  A FEW TORNADOES POSSIBLE

  SCATTERED LARGE HAIL AND ISOLATED VERY LARGE HAIL EVENTS TO 3

    INCHES IN DIAMETER LIKELY

  SCATTERED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 50 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 45 MILES WEST SOUTHWEST OF

YANKTON SOUTH DAKOTA TO 60 MILES EAST NORTHEAST OF SIOUX CITY

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

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).



PRECAUTIONARY/PREPAREDNESS ACTIONS...



REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND 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.



&&



OTHER WATCH INFORMATION...CONTINUE...WW 311...WW 313...WW 314...



DISCUSSION...THUNDERSTORM INITIATION IS EXPECTED SOON ALONG THE WARM

FRONT NEAR THE NE NEB/SE SD BORDER.  THE COMBINATION OF STRONG

BUOYANCY /MLCAPE IN EXCESS OF 4000 J PER KG/...EFFECTIVE BULK SHEAR

AOA 40 KT...AND EFFECTIVE SRH IN EXCESS OF 200 M2/S2 WILL FAVOR A

RISK FOR TORNADOES AND VERY LARGE HAIL WITH INITIAL DISCRETE

SUPERCELLS.  BY LATE EVENING...STORMS SHOULD GROW UPSCALE INTO A

CLUSTER OR TWO WHILE MOVING EWD INTO IA...WITH AN INCREASING RISK

FOR DAMAGING WINDS BY EARLY TONIGHT.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

600. MEAN STORM MOTION VECTOR 27020.





...THOMPSON

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