2026 Mid-Atlantic Severe Storm General Discussion

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Updated afternoon Day 3 SPC disco

Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0227 PM CDT Thu Jul 16 2026

   Valid 181200Z - 191200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE
   OHIO VALLEY AND LOWER GREAT LAKES INTO THE MID-ATLANTIC...

   ...SUMMARY...
   Strong to severe thunderstorms are expected across portions of the
   Ohio Valley and lower Great Lakes into the Mid-Atlantic, mainly
   Saturday afternoon into the evening. Some threat may linger into
   late Saturday night.

   ...Ohio Valley into the Mid Atlantic and vicinity...
   Some amplification of a mid/upper-level trough is expected over the
   northeastern CONUS on Saturday, as multiple shortwaves move through
   the base of the trough. The primary surface low is expected to
   deepen as it moves across southern Quebec toward northern Maine. A
   trailing cold front will move through parts of the Ohio Valley and
   Northeast. A remnant surface front initially draped from western PA
   toward the Delmarva region is forecast to lift northeastward as a
   warm front through the period. 

   As deep-layer flow strengthens atop a richly moist and destabilizing
   warm sector, organized severe potential is expected to develop
   across a relatively broad region from the Ohio Valley into the Mid
   Atlantic, with at least an isolated threat potentially reaching
   parts of New England. Uncertainties include the influence of
   early-day convection and potential persistent smoke on the
   northeastward extent of substantial surface-based destabilization. 

   Along the cold front, the greatest relative threat is currently
   expected from the lower Great Lakes into eastern parts of the Ohio
   Valley, where stronger 850-700 mb flow (around 25-40 kt) is
   forecast. Organized cells/clusters capable of damaging wind and
   isolated hail may evolve along/ahead of the front and spread
   eastward. Rich boundary-layer moisture and modest enhancement to
   low-level SRH may also result in some tornado threat, depending on
   storm-mode evolution. Favorable moisture/buoyancy will also extend
   westward along/ahead of the front into parts of the Midwest and
   lower Ohio Valley, but there may be more of a tendency for
   convection to be undercut by the front with westward extent. 

   Farther south/east, organized convection may evolve or reintensify
   near the effective warm front by afternoon into parts of PA/NJ, and
   also develop into parts of MD/VA along/east of a surface trough.
   Very warm temperatures and steepening low-level lapse rates will
   become supportive of damaging-wind potential, and isolated hail may
   also occur. Some tornado threat could also evolve in closer
   proximity to the warm frontal zone. 

   An extensive frontal QLCS may develop by evening, and continue to
   pose some wind-damage threat for as long as it persists into
   Saturday night.