SPC AC 041944

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0244 PM CDT Sun Jun 04 2023

   Valid 042000Z - 051200Z

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS SOUTH
   TEXAS...PARTS OF THE SOUTHERN APPALACHIANS TO TENNESSEE VALLEY...AND
   SOUTH-CENTRAL LOUISIANA...

   ...SUMMARY...
   Isolated severe thunderstorms are possible across south Texas, 
   parts of the southern Appalachians to Tennessee Valley, and
   south-central Louisiana into this evening.

   ...20Z Update...

   ...South-Central LA...
   Temperatures have climbed into the upper 80s and low 90s across
   south-central LA, amid dewpoints in the upper 60s. Thunderstorms
   have developed in the BTR vicinity, and are moving
   westward/southwestward into the steep low-level lapse rates
   environment downstream. As a result, there appears to be a corridor
   of slightly greater risk for damaging gusts over this area.

   ...South TX...
   As mentioned in MCD #935 and the previous outlook, isolated severe
   storms are possible later this afternoon across south TX.
   Destabilization continues south and west of an MCV (and associated
   cloud cover), with thunderstorm initiation ongoing on remnant
   outflow from south of JCT to HDO to about 20 miles west of SAT.
   Another outflow boundary, this one oriented more north to south,
   extends from near HDO southward/south-southeastward through ALI.
   Cumulus is building along this boundary as well, with additional
   thunderstorms possible here as well. Moderate buoyancy and modest
   shear could support of a few more robust updrafts, which could
   produce hail and localized severe gusts.

   ...Southern Appalachians to TN Valley...
   Overall storm coverage is still expected to increase across the
   region over the next few hours, with several multicell clusters
   possible. Earlier cloud cover has tempered heating across northern
   GA and adjacent portions of southeastern TN, limiting heating and
   keeping low-level lapse rates modest. However, skies and clearing
   and the resultant heating could steepen low-level lapse rates enough
   to support a few damaging gusts. Steep low-level lapse rates are
   already in place across western and middle TN, where additional
   storm development in ongoing. Damaging gusts are possible with these
   storms as well.

   ..Mosier.. 06/04/2023

   .PREV DISCUSSION... /ISSUED 1117 AM CDT Sun Jun 04 2023/

   ...South TX...
   In the wake of several clusters that resulted in extensive
   convective overturning yesterday afternoon through last night,
   appreciable buoyancy (MLCAPE in excess of 2000 J/kg) should largely
   be confined to south TX later this afternoon. With minimal
   large-scale ascent and light low-level winds through tonight,
   convective development appears ill-defined, but may be initially
   focused to the south of a remnant MCV in central TX. 20-30 kt
   mid-level northwesterlies should offer adequate deep shear to
   support a few transient supercells and multicell clustering. Amid
   more moderate mid-level lapse rates compared to yesterday, isolated
   severe hail and wind will be possible into this evening.

   ...Southern Appalachians to TN Valley...
   A belt of 15-25 kt mid-level north-northeasterlies will persist
   across the WV portion of the Appalachians owing to peripheral
   influence of a quasi-stationary mid/upper low near the New England
   coast. This should be adequate to support small to marginally severe
   hail in isolated storms that form in and south of this region, along
   with locally strong gusts later this afternoon. Farther
   west-southwest, weak deep-layer shear will mitigate organized severe
   storms, but sporadic microbursts will remain possible where moderate
   buoyancy can develop.

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