SPC AC 240600

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0100 AM CDT Wed Mar 24 2021

   Valid 251200Z - 261200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER A LARGE
   PART OF MISSISSIPPI...PORTIONS OF CENTRAL AND NORTHERN ALABAMA AND
   ADJACENT AREAS OF WESTERN AND MIDDLE TENNESSEE...

   ...SUMMARY...
   A potential outbreak of severe storms including several long track
   strong tornadoes, large hail and damaging wind will exist Thursday
   into Thursday evening across a portion of the lower Mississippi
   Valley and Southeast States.

   ...Lower Mississippi Valley and Southeast States...

   Shortwave trough currently over the Southwest States will move from
   southern TX early Thursday through the lower MS Valley during the
   day and into the OH Valley overnight. Thursday morning a cold front
   will extend from the Great Lakes southwest to a weak surface low in
   northeast TX, then south into the western Gulf. In response to the
   ejecting negative-tilt shortwave trough, the cyclone is forecast by
   some models to undergo significant deepening as it develops
   northeast during the day. As this occurs, a cold front will
   accelerate through the lower MS Valley into the Southeast States,
   while a warm front initially from northeast TX into northern LA,
   central MS and southwest AL develops northward into the TN Valley.
   Some model differences do exist with the NAM being slightly less
   amplified and more progressive with resulting weaker cyclogenesis.

   It still appears likely that elevated storms will be in progress at
   the start of the period within the warm advection regime across
   northern MS, AL and TN. This activity is expected to continue
   lifting northward, allowing for destabilization from the south with
   time. Rich low-level moisture with upper 60s to near 70 F dewpoints
   will advect northward through warm sector contributing to moderate
   instability with up to 2000 J/kg MLCAPE. Discrete storms are
   expected to develop over the lower MS Valley as the surface layer
   destabilizes during the afternoon. The low-level jet will strengthen
   to 60+ kt over the lower MS and TN Valleys in response to forcing
   within exit region of the migratory mid-upper jet accompanying the
   shortwave trough. Vertical wind profiles with very strong shear and
   large 0-1 km hodographs (0-1 km helicity from 300-400 m2/s2) will
   support supercells with low-level mesocyclones capable of producing
   strong tornadoes and large hail. Some bowing structures are also
   likely. Activity will spread northeast through the lower MS and TN
   valleys during the day and into the evening. Additional storms may
   also develop along the cold front with linear structures capable of
   damaging wind.

   A secondary area of thunderstorm development might occur in vicinity
   of the ejecting vorticity maximum and near and just south of the
   surface low track from northern AR into southern MO. All hazards
   will be possible in this region, but threat is more conditional at
   this time given uncertainty regarding how much destabilization can
   occur. Will maintain this region in a SLGT for now, but continue to
   monitor for upgrade to higher probabilities in later updates.  

   ...OH Valley...

   Widespread rain and thunderstorms will occur over a large part of
   this region during the day. However, some destabilization should
   occur, especially during the evening fostered by a strengthening
   southerly low-level jet. Potential will exist for a forced line of
   storms to develop along the cold front, near and south of the
   surface low as it tracks northeast through this region during the
   evening and overnight. The primary threats will be damaging wind and
   possibly some QLCS tornadoes.

   ..Dial.. 03/24/2021

   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 1730Z