SPC AC 191958

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0258 PM CDT Mon Jun 19 2023

   Valid 192000Z - 201200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE SOUTHEAST...NORTHERN PLAINS...AND CENTRAL TEXAS...

   ...SUMMARY...
   Severe thunderstorms are possible today over parts of the Southeast,
   central Texas, Arklatex, and northern Plains.

   ...20Z Update...
   The only meaningful change to the outlook has been to introduce a
   small Slight Risk across parts of central TX. Temperatures have
   soared into the low to mid 100s amid upper 60s to low 70s surface
   dewpoints to the east of a dryline. Recent visible satellite imagery
   shows convective initiation occurring east of San Angelo TX. Even
   though large-scale ascent will remain weak, any thunderstorms that
   can form and be sustained may become supercellular given 35-40 kt of
   deep-layer shear due to modestly enhanced mid/upper-level
   northwesterly winds. An associated threat for very large hail should
   exist given the presence of very strong instability and steep
   mid-level lapse rates. Severe downdraft winds may also occur. For
   more details, see recently issued Mesoscale Discussion 1166 and
   Severe Thunderstorm Watch 340.

   Across the Southeast, tornado potential will likely remain focused
   along/very near the Gulf Coast in MS/AL and the FL Panhandle.
   Multiple areas of low-level rotation, with occasional debris
   signatures, have been noted with convection occurring across these
   areas given favorable low-level shear noted on recent VWPs from
   KMOB/KEVX, etc... In the wake of earlier thunderstorms, a separate
   area of convection has also developed this afternoon across
   south-central AL. This activity may pose an isolated threat for
   damaging winds and hail through the rest of the afternoon into this
   evening as the boundary layer attempts to re-destabilize. See
   Mesoscale Discussion 1165 for more details on the near-term severe
   threat across the central Gulf Coast states.

   No changes have been made to the Slight Risk across parts of eastern
   MT into ND.

   ..Gleason.. 06/19/2023

   .PREV DISCUSSION... /ISSUED 1112 AM CDT Mon Jun 19 2023/

   ...Southern MS/AL to FL Panhandle...
   A large upper trough is present today over much of the eastern
   states, with a corridor of 30-40 knot mid-level winds extending from
   AR into the central Gulf Coast region.  Ample low-level moisture
   remains across much of the southeast, but multiple bouts of
   convection have pushed the main outflow boundary southward into
   southern MS/AL and the FL Panhandle.  Strong afternoon heating will
   help to establish moderate to strong instability along this axis
   where re-development of widely scattered strong/severe storms are
   expected.  Weak forcing mechanisms suggest limited coverage of
   intense storms, but sufficient deep-layer vertical shear and
   proximity to boundaries may result in isolated supercells capable of
   hail, damaging wind gusts, and perhaps a tornado.

   ...Southeast GA/Northeast FL...
   A persistent linear MCS continues to track eastward across southern
   GA and northern FL.  Strong heating ahead of the line has resulted
   in moderate CAPE values and sufficient westerly flow aloft to pose a
   risk of locally gusty/damaging winds for a few more hours until the
   line moves offshore.  Cooler temperatures in the wake of the line
   should limit the redevelopment of severe storms later today.

   ...MT/ND...
   Fast southwesterly flow aloft extends across the northern Rockies
   and High Plains today.  A band of mid/high clouds lies from northern
   WY into eastern MT and western ND.  A consensus of morning model
   solutions indicate that strong heating along and east of the 
   eastern edge of this cloud cover will result in a corridor of steep
   low-level lapse rates and sufficient CAPE for scattered thunderstorm
   development.  Fast-moving supercell and bowing structures appear
   likely this afternoon and evening as storms track from eastern MT
   into western ND.  Damaging winds and hail are the main risks.

   ...Central TX...
   Hot/humid conditions along the surface dryline over central TX will
   pose some risk of isolated thunderstorms by mid/late afternoon. 
   While coverage of these storms may be quite limited, any storm that
   forms in the extremely unstable air will pose a risk of large hail
   and damaging winds.

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