SPC AC 230740

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0240 AM CDT Tue Mar 23 2021

   Valid 251200Z - 261200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER A PORTION
   OF THE LOWER MISSISSIPPI VALLEY AND SOUTHEAST STATES...

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

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

   A robust shortwave trough will move from southern TX early Thursday
   northeast 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 eastern TX, then
   south into the western Gulf. In response to the ejecting shortwave
   trough, the cyclone is forecast to undergo significant deepening as
   it develops northeast during the day. A cold front will accelerate
   through the lower MS Valley and into the Southeast States, while a
   warm front initially from northeast TX into northern LA and central
   MS lifts northward to near the TN border by evening. 

   It is likely that elevated storms will be ongoing in 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. Potential will
   exist for discrete storms to develop in the warm sector as the
   boundary layer destabilizes during the afternoon. Vertical wind
   profiles with very strong shear and large 0-1 km hodographs will
   support supercells capable of producing strong tornadoes and large
   hail. Activity will spread northeast through the lower MS valley
   during the day and into the TN Valley by late afternoon into the
   evening. Additional storms may also develop along the cold front
   with linear structures capable of damaging wind.

   ...OH Valley...

   Widespread early storms during the first half of the day lower
   confidence in more than A SLGT/MRGL risk for this region at this
   time. However, some destabilization is expected by late day or
   during the evening. Potential will exist for a line of storms to
   develop along the cold front with damaging wind and QLCS tornadoes
   the main threats. The SLGT risk may need to be expanded farther
   north in later outlooks.

   ..Dial.. 03/23/2021

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