WWUS20 KWNS 011910
SEL5
SPC WW 011910
IAZ000-NEZ000-SDZ000-020300-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 455
NWS STORM PREDICTION CENTER NORMAN OK
210 PM CDT THU AUG 1 2013

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
  WESTERN IOWA
  NORTHEAST NEBRASKA
  SOUTHEAST SOUTH DAKOTA

* EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 210 PM UNTIL
  1000 PM CDT.

* PRIMARY THREATS INCLUDE...
  SEVERAL LARGE HAIL EVENTS WITH A FEW VERY LARGE HAIL EVENTS TO 2
    INCHES IN DIAMETER POSSIBLE
  SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 60
STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES NORTH
NORTHWEST OF YANKTON SOUTH DAKOTA TO 35 MILES EAST OF COLUMBUS
NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).

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 454...

DISCUSSION...SEVERE STORMS --INCLUDING SUPERCELLS-- CONTINUE TO
DEVELOP THIS AFTERNOON NEAR THE INTERSECTION OF THE SYNOPTIC FRONT
AND AN OUTFLOW BOUNDARY OVER SERN SD INTO N-CNTRL AND NERN NEB. 
THIS ACTIVITY IS FORMING WITHIN A MODERATELY UNSTABLE AIR MASS WHICH
COINCIDES WITH RELATIVELY STRONG DEEP-LAYER SHEAR.  THESE STORMS ARE
EXPECTED TO SPREAD SEWD ACROSS THE WATCH AREA THIS AFTERNOON INTO
EVENING WITH A RISK FOR LARGE HAIL AND DAMAGING WIND GUSTS.

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 32020.


...MEAD