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Mesoscale Discussion 897
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   Mesoscale Discussion 0897
   NWS Storm Prediction Center Norman OK
   1059 AM CDT Sun May 28 2017

   Areas affected...Parts of southern
   Louisiana/Mississippi/Alabama/Georgia and the Florida panhandle

   Concerning...Severe potential...Watch unlikely 

   Valid 281559Z - 281800Z

   Probability of Watch Issuance...20 percent

   SUMMARY...Intensifying thunderstorm development is expected across
   southern portions of the central Gulf states and associated coastal
   areas through 18-21Z.  This probably will be accompanied by at least
   some localized severe weather potential.  It is not yet clear that a
   watch will be needed, but trends will be monitored.

   DISCUSSION...Forcing for ascent along the leading edge of outflows
   associated with extensive overnight convective development is
   maintaining a narrow corridor of sustained thunderstorm development.
   The composite outflow boundary has been steadily advancing
   southward, and appears likely to progress south of the stronger
   westerlies, toward Gulf coastal areas, through 18-21Z.  However,
   mid-level height falls and the southward suppression of a lingering
   plume of warm elevated mixed layer air, coupled with insolation, are
   contributing to weakening of inhibition for seasonably moist
   boundary layer air ahead of activity.  This may lead to a general 
   intensification of thunderstorm development during the next few
   hours, with locally enhanced convergence along the composite outflow
   boundary eventually supporting some rapid intensification  in the
   presence of moderate to large CAPE (on the order of 2000-4000 J/kg).

   This degree of latent instability is being supported by steep
   mid-level lapse rates, which probably will contribute to
   thermodynamic profiles conducive to frequent lightning, some severe
   hail, and locally strong downbursts in the most vigorous storms. 
   Strengthening of the larger-scale cold pool may also support
   increasing gusts along its leading edge which could approach severe
   levels by mid to late afternoon.

   ..Kerr/Hart.. 05/28/2017

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...TAE...MOB...JAN...LIX...LCH...

   LAT...LON   30439358 30289242 30379090 30619022 31018928 31128769
               31258685 31518609 30698540 30208585 29898794 29298924
               29149078 29379320 29709376 30439358 

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Page last modified: May 28, 2017
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