SPC AC 220529

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1229 AM CDT Fri May 22 2020

   Valid 221200Z - 231200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   NORTHERN TEXAS AND OKLAHOMA...

   ...SUMMARY...
   Severe storms will be likely today across parts of the southern
   Plains northeastward into southeast Kansas and the Ozarks. An
   enhanced threat for tornadoes, very large hail and wind damage is
   expected from north Texas into southern and eastern Oklahoma.

   ...Southern and Central Plains/Ozarks...
   An upper-level low will move east-northeastward across the central
   Plains today as an associated trough moves across the southern
   Plains. At the surface, a cold front will move into central Oklahoma
   with a moist airmass located ahead of the front. A line of
   thunderstorms is forecast to move across northern Oklahoma this
   morning into the Ozarks this afternoon. South of the outflow
   boundary, a moist and unstable airmass will remain in place from
   north Texas into eastern Oklahoma, where moderate to strong
   instability is expected to develop by early afternoon. MLCAPE values
   should peak in the 3500 to 4500 J/kg range from near Wichita Falls,
   Texas northeastward to south of Tulsa, Oklahoma. Convection is
   forecast to initiate along this corridor during the late afternoon
   with several discrete storms moving eastward across eastern and
   southern Oklahoma. During the early evening, storms will also likely
   develop in north and west-central Texas.

   In addition to strong instability, RAP forecast soundings in parts
   of the southern Plains show a favorable wind profile for supercells.
   In southeast Oklahoma and north Texas, winds are forecast to veer
   with height in the lowest 3 km AGL with speed shear in the
   mid-levels. This combined with 700-500 mb lapse rates near 8.0 C/km
   will be favorable for large hail with the stronger updrafts.
   Hailstones of greater than 2 inches in diameter will be possible
   with supercells co-located with the greatest instability. A tornado
   threat is also expected to develop as low-level shear gradually
   increases during the late afternoon and early evening. A couple
   strong tornadoes may occur with the more dominant supercells, with
   the greatest potential from between Wichita Falls and Fort Worth
   northeastward to near McAlester, Oklahoma. An Enhanced Risk has been
   added along this corridor.

   The severe threat is expected to extend eastward into northern
   Arkansas during the evening where large hail and wind damage will be
   possible. Further north into western Missouri and eastern Kansas,
   weaker instability should keep any severe threat more isolated. An
   isolated severe threat is also expected in west-central Texas where
   storms are expected to be very widely spaced.

   ...Southern Appalachians/Georgia/Carolinas...
   An upper-level low will move northeastward across the Ohio Valley
   today as an associated trough moves into the southern Appalachians.
   Thunderstorms are expected to develop near the trough around midday
   and move eastward into the Carolinas during the mid to late
   afternoon. More isolated storms may also develop across parts of
   northern Georgia. A moist airmass will be in place from Georgia into
   the Carolinas where surface dewpoints are forecast to be in the 60s
   F. As surface temperatures warm during the day, pockets of moderate
   instability appear likely to develop. This combined with 0-6 km
   shear of 30 to 40 kt and steep low-level lapse rates, should be
   favorable for isolated severe storms. Marginally severe wind gusts
   and hail would be the primary threats.

   ..Broyles/Lyons.. 05/22/2020

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