SPC AC 210737

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0237 AM CDT Tue May 21 2019

   Valid 231200Z - 241200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER A PORTION OF
   THE SOUTHERN AND CENTRAL PLAINS AS WELL AS THE OHIO VALLEY AND
   NORTHEAST STATES...

   ...SUMMARY...
   Severe storms with large hail, damaging wind and tornadoes will be
   possible over a part of the central and southern Plains Thursday.
   Other strong to severe storms with damaging wind and large hail
   might occur from a portion of the Northeast States into the Ohio
   Valley.

   ...Synopsis...

   A significant shortwave trough will rotate through the base of an
   upper low centered over the Great Basin 12Z Thursday and into the
   central High Plains Thursday afternoon and evening. Farther east, a
   low-amplitude shortwave trough will crest an upper ridge anchored
   over the southeast U.S. and move through the Great Lakes before
   turning southeast into the Northeast States Thursday evening. At the
   surface a warm or stationary front will likely extend from the
   middle MS Valley region southwest into central or southern KS. A
   dryline will reside near the TX/NM border. The warm front is
   expected to lift north into southeast NE, while the dryline mixes
   through west TX during the day. Farther east a surface low attending
   the northern-stream shortwave trough will move through southern
   Canada while trailing cold front advances southeast through the
   Great Lakes. A warm front will advance east into a portion of the
   Northeast States.

   ...Central and southern Plains...

   A very moist and unstable airmass with dewpoints in the upper 60s to
   around 70 F will reside in the warm sector from KS to OK and TX
   beneath 7-7.5 C/km mid-level lapse rates, contributing to moderate
   to strong instability (2500-3000 J/kg MLCAPE). While much of the
   warm sector across this region may remain capped, forcing for ascent
   attending the northeast-migrating upper jet will likely promote
   thunderstorm development over the central and southern High Plains.
   Models suggest early timing of this feature and initiate storms near
   and north of the warm front from the TX Panhandle into southwest KS
   early in the period. Some of this activity may intensify as it
   develops northeast, and additional storms are expected to develop
   along the dryline as well as along and north of the warm front.
   Vertical wind profiles and the thermodynamic environment will
   support organized storms including supercells with all hazards
   possible.

   ...Northeast States through Ohio Valley...

   The warm sector will gradually moisten west of the warm front during
   the day with low 60s F dewpoints beneath 6.5 C/km lapse rates along
   with diabatic warming contributing to moderate instability during
   the day. Current indications are that storms will most likely
   develop over the Great Lakes along southeast-advancing cold front
   and spread southeast into the OH Valley and Northeast States by late
   afternoon and evening. Winds will strengthen as the mid-level speed
   max attending the shortwave trough approaches the region with
   effective shear supporting supercells. These storms may produce
   large hail and damaging wind as they move southeast through the
   region later Thursday afternoon into the evening.

   ..Dial.. 05/21/2019

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