

695 

WWUS20 KWNS 192335

SEL7

SPC WW 192335

NEZ000-SDZ000-200400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 497

NWS STORM PREDICTION CENTER NORMAN OK

635 PM CDT MON JUL 19 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN NEBRASKA

       SOUTH CENTRAL SOUTH DAKOTA



EFFECTIVE THIS MONDAY EVENING FROM 635 PM UNTIL 1100 PM CDT.



HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 60

STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES NORTH

NORTHEAST OF PIERRE SOUTH DAKOTA TO 25 MILES WEST OF BURWELL

NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



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 495...WW 496...



DISCUSSION...DESPITE SLOWLY STRENGTHENING CAPPING INVERSION...

COMBINATION OF WEAK UPPER WAVE AND 60-70 KT DEEP LAYER SHEAR IS

EXPECTED TO MAINTAIN THREAT FOR SEVERE STORMS THE NEXT FEW

HOURS...AS STORMS TRACK SEWD AT 30-35 KT. THE VERY STRONG DEEP LAYER

SHEAR AND MODERATE TO STRONG INSTABILITY WILL SUPPORT SUPERCELLS AND

SMALL BOWS.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 30030.





...IMY

