The SPC is forecasting ...Severe thunderstorms expected over parts of the the Ozarks to lower Ohio Valley later today and tonight....   Please read the latest public statement about this event.  View What is a Watch? clip.

   SPC AC 271619

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1119 AM CDT Sat May 27 2017

   Valid 271630Z - 281200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
   SOUTHEAST KS...NORTHEAST OK...NORTHERN AR...SOUTHERN AND CENTRAL
   MO...SOUTHERN IL...WESTERN KY...AND NORTHWEST TN...

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN
   KS/OK INTO EASTERN KY/TN...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL
   PLAINS TO THE MID-ATLANTIC REGION...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
   SOUTHEAST CO...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER MUCH OF THE
   CENTRAL AND SOUTHERN PLAINS...EASTWARD TO THE MID-ATLANTIC STATES...

   ...SUMMARY...
   Widespread severe wind gusts are forecast from the Ozark region to
   the lower Ohio Valley this afternoon and evening.  Additionally,
   very large to giant hail and tornadoes will be possible from the Red
   River Valley northeastward to the Ozark Plateau. Damaging winds,
   large hail, and a couple tornadoes will also be possible across the
   Tennessee Valley, middle Ohio Valley, and portions of the
   Mid-Atlantic.

   ...Eastern OK into the mid Mississippi Valley...
   A significant severe weather event is forecast across this part of
   the nation today, with widespread severe storms likely later this
   afternoon and tonight.  12z and subsequent model guidance shows
   substantial uncertainty regarding the details of the convective
   evolution later today, so little changes have been made to the
   ongoing forecast areas.

   It appears likely that clusters of intense thunderstorms will form
   by mid afternoon over parts of southeast KS/western MO/far northeast
   OK, in vicinity of remnant boundaries and where extreme instability
   is present.  A potent combination of MLCAPE values over 5000 J/kg
   and effective helicity of 200-300 m2/s2 suggests that initial storms
   will likely become supercellular with a risk of giant hail and
   tornadoes (perhaps strong).  An evolution toward bow/lewp structures
   is indicated by all model solutions, with one or more fast-moving
   bow echoes likely to track from southern MO into western KY this
   evening.  This potential derecho would result in widespread and
   potentially significant wind damage.

   Initiation of thunderstorms farther southwest into OK is less
   certain due to a strong cap and subtle forcing, but those storms
   that form will also likely become supercellular with a risk of very
   large hail and a few tornadoes.  These storms may spread into parts
   of AR after dark.

   ...TN Valley into the Mid Atlantic...
   Water vapor loop shows a mid level shortwave trough over KY/TN. 
   Lift ahead of this feature will encourage scattered thunderstorm
   development from eastern KY/TN into WV/VA/NC this afternoon. 
   Forecast soundings show moderate CAPE values and strong westerly
   flow aloft, supporting organized/supercell storms capable of large 
   hail and damaging wind gusts.

   ...Southeast CO...
   Moist/northeasterly upslope flow over southeast CO today will
   encourage afternoon/evening thunderstorm development.  Those storms
   that form will pose a risk of large hail for several hours before
   weakening after dark.

   ..Hart/Gleason.. 05/27/2017

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z