MESOSCALE DISCUSSION 1652
   NWS STORM PREDICTION CENTER NORMAN OK
   0741 PM CDT THU JUL 23 2009
   
   AREAS AFFECTED...PORTIONS OF CNTRL NEB / NWRN KS / ERN CO
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 614...
   
   VALID 240041Z - 240145Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 614
   CONTINUES.
   
   THE THREAT FOR ISOLD LARGE HAIL WITH PERHAPS A DMGG WIND GUST OR TWO
   WILL CONTINUE TO BE POSSIBLE FROM PARTS OF ERN CO/WRN KS NNEWD INTO
   THE NEB SANDHILLS.  SHORT TERM TORNADO POTENTIAL APPEARS CONFINED TO
   NEAR THE MID PORTION OF THE PLATTE RIVER VALLEY WHERE BACKED WINDS
   AND MOIST LOW LEVELS ARE CONTRIBUTING TO LOW LEVEL STORM
   ROTATION...IN ADDITION TO A VERY LARGE HAIL THREAT.
   
   SURFACE MESOANALYSIS IN THE PAST HOUR INDICATES SEVERAL OUTFLOW
   BOUNDARIES EMANATING FROM EARLIER/ONGOING CONVECTION SURGING AWAY
   FROM THE DISCUSSION AREA.  THE AIRMASS HAS PARTIALLY BEEN
   CONVECTIVELY OVERTURNED OVER PORTIONS OF THESE AFFECTED AREAS...AND
   WITH LITTLE IN THE WAY OF DEEP CUMULUS GROWTH ALONG THE LEADING EDGE
   OF THE OUTFLOWS...AT THIS POINT NOT EXPECTING AN INCREASE IN STORM
   COVERAGE FROM OVER THE NWRN HALF OF THE WW.  
   
   AREAS NEAR THE MID PLATTE RIVER VALLEY...VERY STEEP LAPSE RATES
   THROUGH A DEEP LAYER ARE EXHIBITED ON THE LBF 00Z RAOB.  THIS ALONG
   WITH MESOSCALE AREA OF HIGHER QUALITY MOISTURE CHARACTERIZED BY
   MID-UPPER 60S SURFACE DEWPOINTS HAS CONTRIBUTED TO A STRONGLY
   UNSTABLE AIRMASS /NEAR 3000 J/KG MLCAPE/.  DESPITE SEEMINGLY
   MARGINAL 20 KT NWLY H5 FLOW...BACKED SELY SURFACE WINDS ARE
   CONTRIBUTING TO EFFECTIVE SRH VALUES EXCEEDING 300 M2/S2 AND
   SOMEWHAT SUPPORTIVE OVERALL 0-6 KM SHEAR AROUND 30 KTS. 
   ELSEWHERE...STORMS MAY BE CAPABLE OF ISOLD LARGE HAIL/DMGG WINDS.
   
   ..SMITH.. 07/24/2009
   
   
   ATTN...WFO...GID...LBF...DDC...GLD...PUB...BOU...
   
   LAT...LON   39800063 38320132 37690214 37720264 38440284 39410315
               39730304 40410192 41840134 42860033 42959954 42669904
               41899925 40739992 39800063