MESOSCALE DISCUSSION 2011
   NWS STORM PREDICTION CENTER NORMAN OK
   0618 PM CDT THU AUG 18 2011
   
   AREAS AFFECTED...PARTS OF CENTRAL/ERN NEB...FAR WRN IA...AND FAR
   NWRN MO
   
   CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY 
   
   VALID 182318Z - 182345Z
   
   THREAT FOR ADDITIONAL TORNADOES SHOULD INCREASE THIS EVENING ACROSS
   FAR WRN IA...ERN NEB INTO NRN NEB.  A TORNADO WATCH WILL LIKELY BE
   ISSUED TO REPLACE PART OF WW 785...AND INCLUDE AREAS NWWD INTO NRN
   NEB.
   
   EARLY EVENING SURFACE ANALYSIS SHOWED A WARM FRONT EXTENDING FROM
   SWRN SD ESEWD THROUGH NRN NEB /JUST S OF ANW/ TO SERN HOLT
   COUNTY...WITH THIS BOUNDARY THEN EXTENDING SEWD INTO SERN NEB AND
   FAR ERN KS.  HIGH THETAE AIR MASS EXISTS INVOF OF THIS WARM FRONT
   WITH SURFACE DEWPOINTS IN THE LOWER 70S EXTENDING FROM THE ERN HALF
   OF NEB INTO NORTH CENTRAL NEB.  AREA WIND PROFILER DATA SHOWED A
   STRENGTHENING SLY LLJ ACROSS THE ERN HALF OF NEB WITH SUBSEQUENT
   INCREASE IN LOW LEVEL SHEAR /EFFECTIVE SRH 100-300 M2 PER S2/ WHICH
   WILL CONTINUE TO SUPPORT A THREAT FOR A FEW TORNADOES.  THIS THREAT
   EXTENDS NWWD INTO NORTH CENTRAL NEB AS A STRONG TO SEVERE STORM
   TRACKS SEWD FROM BENNETT COUNTY SD /SRN EXTENT OF WW 786/ INTO NRN
   NEB.
   
   ..PETERS.. 08/18/2011
   
   
   ATTN...WFO...DMX...EAX...FSD...OAX...GID...LBF...UNR...
   
   LAT...LON   42250106 42650153 43020188 43049945 42969792 42829640
               42059555 41109505 40189502 40039532 40079636 40289749
               40539836 42250106