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097 

WWUS20 KWNS 060755

SEL2

SPC WW 060755

NEZ000-SDZ000-061500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 472

NWS STORM PREDICTION CENTER NORMAN OK

250 AM CDT TUE AUG 6 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  NORTHERN NEBRASKA

  SOUTHERN SOUTH DAKOTA



* EFFECTIVE THIS TUESDAY MORNING FROM 250 AM UNTIL 1000 AM CDT.



* PRIMARY THREATS INCLUDE...

  SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

  A FEW LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 50

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 115 MILES WEST

NORTHWEST OF VALENTINE NEBRASKA TO 20 MILES EAST OF ONEILL

NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).



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 471...



DISCUSSION...SLIGHTLY ELEVATED TSTM CLUSTER HAS STRENGTHENED IN THE

PAST HALF HOUR OVER SW SD...SW OF PHP. ADDITIONAL STORMS ALSO HAVE

STRENGTHENED ALONG AXIS OF ENHANCED LOW-LVL WAA FARTHER SE NEAR THE

SD-NEB BORDER N OF ANW. RAPID CITY VWP HAS SHOWN AN INCREASE IN DEEP

WNW FLOW OVER THE PAST 90 MINUTES...WITH THE 3 KM WIND SPEED NOW 50

KTS. THIS INCREASE MAY BE RELATED TO THE ESE PROGRESSION OF UPR

IMPULSE NOW OVER ERN MT. CONTINUED ESE MOTION OF THE

DISTURBANCE...THE PRESENCE OF EML PLUME DOWNSTREAM ACROSS THE NRN

PLNS...AND MOIST/SSWLY LWR TROPOSPHERIC FLOW OVER NEB TOGETHER

SUGGEST A POTENTIAL FOR CONTINUED STORM INTENSIFICATION...AND THE

POSSIBILITY FOR BOWING SEGMENTS WITH DMGG WIND/SVR HAIL.



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 500. MEAN STORM

MOTION VECTOR 30030.





...CORFIDI

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