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Mesoscale Discussion 439
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   MESOSCALE DISCUSSION 0439
   NWS STORM PREDICTION CENTER NORMAN OK
   0843 PM CDT SUN APR 27 2014

   AREAS AFFECTED...PORTIONS OF ERN OK...AR...SERN MO

   CONCERNING...TORNADO WATCH 100...102...103...

   VALID 280143Z - 280245Z

   THE SEVERE WEATHER THREAT FOR TORNADO WATCH
   100...102...103...CONTINUES.

   SUMMARY...THE RISK FOR SEVERE THUNDERSTORMS INCLUDING TORNADOES
   CONTINUES ACROSS TORNADO WATCHES 100...102...AND 103.

   DISCUSSION...THE ONGOING SEVERE THUNDERSTORM AND TORNADO POTENTIAL
   ACROSS TORNADO WATCHES 100...102...AND 103 IS EVOLVING IN TWO
   REGIMES:

   /1/ PRE-FRONTAL SEMI-DISCRETE/DISCRETE SUPERCELLS ARE ADVANCING NEWD
   FROM CNTRL AR INTO NERN AR AIDED BY A STRENGTHENING LLJ. UPPER
   60S/LOWER 70S SFC-DEWPOINT AIR IS RETREATING NEWD TO SUPPORT
   LOWERING OF EFFECTIVE INFLOW LAYERS FOR THE ONGOING CONVECTION.
   AND...WITH AROUND 450-600 M2/S2 OF 0-1-KM SRH INDICATED BY RECENT
   LZK VWP DATA THAT DEPICT A LONG...LOOPING LOW-LEVEL
   HODOGRAPH...TORNADOES -- SOME POSSIBLY SIGNIFICANT -- MAY ACCOMPANY
   THIS ACTIVITY. LARGE HAIL AND DAMAGING WINDS WILL ALSO BE POSSIBLE.

   /2/ WATER VAPOR LOOPS IMPLY AN ARCING BAND OF ENHANCED MID-LEVEL
   ASCENT/MOISTURE OVERTAKING A STALLED BOUNDARY OVER SERN
   OK...SUPPORTING THE INITIATION OF CONVECTION. THIS ACTIVITY WILL
   LIKELY EXHIBIT QUASI-LINEAR MODES AS IT DEVELOPS ALONG THE FRONT AND
   WILL POSE THE RISK FOR DMGG WINDS AND LARGE HAIL. SRX VWP DATA
   INDICATE AROUND 25-30 KT OF 0-1-KM BULK SHEAR SUGGESTING SOME
   TORNADO THREAT WILL EXIST AS WELL...AS THIS ACTIVITY SPREADS EWD
   ACROSS SERN/E-CNTRL OK AND EVENTUALLY INTO PARTS OF WRN AR.

   ..COHEN.. 04/28/2014


   ATTN...WFO...PAH...MEG...LZK...SGF...SHV...TSA...

   LAT...LON   35249506 35759320 36159216 36709067 36869001 36208976
               35209017 34599098 33769235 33609387 34009568 35249506 

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Page last modified: April 28, 2014
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