The SPC is forecasting ...Severe thunderstorms expected over parts of the northern Plains today and tonight....   Please read the latest public statement about this event.  View What is a Watch? clip.

   SPC AC 281616

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1116 AM CDT Thu Jun 28 2018

   Valid 281630Z - 291200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
   EASTERN MONTANA...MUCH OF NORTH DAKOTA...AND NORTHWEST SOUTH
   DAKOTA...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
   NORTHERN PLAINS...AND OVER PARTS OF THE TENNESSEE VALLEY AND
   SOUTHEAST STATES...

   ...SUMMARY...
   Severe thunderstorms are likely across the northern Plains,
   especially this afternoon and tonight, with the potential for very
   large hail, widespread damaging winds, and a few tornadoes. Other
   severe storms can be expected across the middle to lower Missouri
   Valley and the Southeast States.

   ...Northern Plains...
   Isolated severe thunderstorms have been ongoing this morning in area
   of low-level warm advection over ND and MN.  Locally intense storms
   will remain possible through the afternoon in this regime, with
   large hail and damaging winds possible.  

   By mid/late afternoon, the influence of a strong upper trough in the
   western states will begin to affect western/central MT.  Favorable
   heating, dewpoints in the 50s, and strong winds aloft will promote a
   few severe storms capable of hail and wind.  As this activity
   spreads eastward, more robust convection should develop in the
   eastern plains of MT, with supercells and very large hail possible. 
   A few tornadoes may also occur in this region before storms
   merge/congeal into multiple bowing line segments.  Damaging wind
   threat will likely become rather widespread across parts of ND after
   dark.

   Several 12z model runs suggest a risk of a linear MCS tracking into
   parts of MN/WI overnight.  Have expanded the MRGL risk to account
   for this potential.

   ...TN Valley into Southeast states...
   A band of strong thunderstorms extends from western KY, across
   middle TN, into northern GA.  These storms are expected to build
   southward through the day, into a very moist and unstable air mass. 
   Winds aloft are just strong enough for a few multicell clusters
   posing a risk of organized damaging wind potential.  Southward
   extent of storms will be modulated by mesoscale organization, but
   may reach into north FL before weakening.

   ...Northeast...
   A moist boundary layer is present today over parts of NY/NJ and
   southern New England, with dewpoints in the 70s.  Scattered
   thunderstorms are expected to form this afternoon and spread across
   the MRGL risk area.  Thermodynamic parameters are weak, but low/mid
   level winds are sufficiently strong for a few wind gusts in the most
   intense cells.

   ..Hart/Bentley.. 06/28/2018

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