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WWUS20 KWNS 182248

SEL3

SPC WW 182248

NDZ000-SDZ000-190600-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 173

NWS STORM PREDICTION CENTER NORMAN OK

545 PM CDT SAT MAY 18 2013



THE NWS STORM PREDICTION CENTER HAS ISSUED A



* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

  SOUTHERN AND CENTRAL NORTH DAKOTA

  CENTRAL SOUTH DAKOTA



* EFFECTIVE THIS SATURDAY AFTERNOON AND SUNDAY MORNING FROM 545

  PM UNTIL 100 AM CDT.



* PRIMARY THREATS INCLUDE...

  NUMEROUS LARGE HAIL EVENTS LIKELY 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 75

STATUTE MILES EAST AND WEST OF A LINE FROM 50 MILES NORTH

NORTHEAST OF BISMARCK NORTH DAKOTA TO 50 MILES SOUTHEAST OF

PIERRE SOUTH DAKOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).



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 170...WW 171...WW 172...



DISCUSSION...TSTMS EXPECTED TO INCREASE IN NUMBER AND STRENGTH

ACROSS WW AREA THIS EVE AS BAND OF WEAK LARGE SCALE ASCENT

OVERSPREADS AXIS OF MODERATE SFC-BASED INSTABILITY EXTENDING NEWD

INTO REGION ALONG INVERTED SFC TROUGH. 40+ KT SWLY DEEP SHEAR AND

PERSISTENT LOW-LVL MOISTURE INFLOW SUGGEST POTENTIAL FOR A FEW

SUSTAINED STORMS/SUPERCELLS WITH SVR HAIL/WIND. ACTIVITY MAY MERGE

INTO A BROKEN SQLN LATER TNGT...WITH A CONTINUED RISK FOR SVR

WIND/HAIL AND POSSIBLY A TORNADO.



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 24025.





...CORFIDI

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