SPC AC 161959

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0259 PM CDT Fri Jun 16 2023

   Valid 162000Z - 171200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
   THE MID-ATLANTIC REGION...CENTRAL HIGH PLAINS...AND FROM THE
   ARKANSAS VICINITY SOUTHEASTWARD INTO THE FLORIDA PANHANDLE AND
   SOUTHWESTERN GEORGIA...

   ...SUMMARY...
   Large hail and damaging thunderstorms winds are possible across
   parts of the central High Plains, Southeast U.S. and Mid-Atlantic.

   ...Discussion...
   Little in the way of substantive changes are being implemented to
   the outlook at this time, as reasoning and areas laid out in the
   prior package remain consistent with current and expected trends. 
   The most substantial change has been to expand the SLGT risk area in
   the lower Mississippi Valley region a bit farther northwestward,
   toward the Ozarks, where storms are currently increasing in coverage
   and may pose local hail/wind risk greater than previously
   anticipated.  For additional short-term information, please refer to
   SWOMCD #1107.

   ..Goss.. 06/16/2023

   .PREV DISCUSSION... /ISSUED 1130 AM CDT Fri Jun 16 2023/

   ...Mid Atlantic...
   A prominent mid-level trough and associated 50 knot jet max is
   rotating across the Mid-Atlantic region today.  Scattered
   thunderstorms have already formed along the surface cold front over
   eastern PA and NJ.  These storms will track eastward and offshore,
   while new activity builds southward into eastern MD/VA.  Cool
   temperatures aloft, steep mid-level lapse rates, and favorable
   deep-layer vertical shear will provide support for strong-severe
   storms capable of damaging winds and hail through the late
   afternoon.

   ...CO/KS...
   Morning model guidance hints at a weak shortwave trough over
   northern NM approaching the High Plains.  Ahead of the trough,
   strong daytime heating/destabilization is occurring along and south
   of a surface boundary paralleling the Palmer Ridge.  Scattered
   thunderstorms are expected to develop in the instability axis by
   mid-afternoon, tracking eastward into western KS this evening. 
   Early storms will be discrete, with a few supercells producing large
   hail. As the storms build eastward, upscale growth into bowing
   structures is expected, with an increasing risk of locally damaging
   wind gusts.

   ...AR to AL...
   Scattered showers and thunderstorms have developed this morning over
   northwest AR - ahead of a mid-level shortwave trough over northeast
   OK.  The air mass ahead of these storms over AR/MS is very moist and
   unstable, with afternoon MLCAPE values expected to reach 3000 J/kg. 
   Storms are expected to intensify to severe levels by mid-afternoon
   and track southeastward.  Morning CAM solutions vary in the
   timing/placement of the corridor of greatest risk, ranging from
   northern MS/AL into northern LA.  Regardless, clusters of storms are
   expected this evening tracking into parts of AL before weakening. 
   Damaging winds and hail will be possible in the strongest cells.

   ...FL Panhandle...
   A long-lived MCS is finally decaying as it tracks across the central
   FL panhandle.  This activity is likely to dissipate by mid
   afternoon, with only a marginal risk of new storms forming on the
   remnant outflow boundaries.

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