SPC AC 221807

   Day 2 Convective Outlook CORR 1
   NWS Storm Prediction Center Norman OK
   0107 PM CDT Wed May 22 2019

   Valid 231200Z - 241200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS THE OH
   VALLEY/MIDDLE ATLANTIC AND SOUTHERN/CENTRAL PLAINS...

   CORRECTED FOR MISSING THUNDER LINE

   ...SUMMARY...
   Severe storms with large hail, damaging wind and tornadoes will be
   possible over a part of the central and southern Plains Thursday.
   Other severe storms with a threat for mainly damaging wind and large
   hail are expected from a portion of the Ohio Valley into the
   northern Middle Atlantic.

   ...Upper OH Valley/Northern Middle Atlantic...

   Central US short-wave trough is forecast to eject northeast across
   the Great Lakes and flatten the eastern ridge as 80kt 500mb speed
   max translates across Lake Erie. This feature is expected to aid
   early-morning convection across the OH Valley which will propagate
   into eastern OH/western PA by 18z. Depending on the evolution of
   this convection it appears environmental shear will become favorable
   for sustaining fast-moving organized updrafts. Latest model guidance
   suggests upward-evolving thunderstorms by early afternoon within
   strengthening westerly flow regime. Boundary-layer heating is
   expected to be maximized from south-central PA, south along the lee
   of the central Appalachians. If a cold pool develops early, severe
   thunderstorms should initiate along the
   eastern-southern-southwestern flank of this activity then
   spread/develop east-southeast toward the Delmarva. Several CAMs
   solutions support this scenario and will extend higher severe probs
   into northern MD to account for the more southeast propagational
   component. Damaging winds, and some hail, are expected with
   convection as it spreads across eastern OH/PA toward northern MD by
   late afternoon.

   ...Central/Southern Plains...

   Strong mid-level flow is forecast to round the base of western US
   trough over northern Mexico late day1 into early day2, then
   translate into the central High Plains by 24/00z. In response to
   this feature, LLJ should strengthen across the TX south Plains late
   Wednesday. This will allow for a substantial moisture surge to at
   least 102W longitude where higher terrain and heating along the
   western edge of this moist plume should contribute to robust
   convection. There is some concern that convection could develop
   early in the period along the nose of the LLJ. This activity is most
   likely across the northern TX Panhandle into western KS atop cooler
   boundary air mass that will sag south across the High Plains. This
   early-day convection will likely be elevated and pose primarily a
   large hail threat. However, strong surface heating near the NM/TX
   border will contribute to substantial buoyancy that will become
   uncapped by late afternoon. Forecast shear profiles strongly favor
   supercells and a fair number of storms should ultimately evolve
   across the ENH Risk. High-PW air mass should surge into this region
   such that long-lived supercells are expected. Very large hail and
   tornadoes can be expected with supercells south of the cold front
   that will orient itself across southwest-central KS. If early-day
   convection is less than currently expected, a corridor of higher
   severe probs may ultimately need to be considered across the High
   Plains south of the front.

   ...MAXIMUM RISK BY HAZARD...
   Tornado:  10%     - Enhanced
   Wind:     30%     - Enhanced
   Hail:     30% SIG - Enhanced

   ..Darrow.. 05/22/2019

   CLICK TO GET WUUS02 PTSDY2 PRODUCT

   NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0600Z