Severe weather outlook: Marginal risk of severe thunderstorms across DE, MD, NJ, NY

SPC AC 121248 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 AM CST Thu Nov 12 2026 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE COASTAL MID-ATLANTIC... ...SUMMARY... Strong to severe thunderstorms capable of producing isolated severe hail, damaging winds, and perhaps a tornado may impact parts of the coastal Mid-Atlantic this afternoon. ...Coastal Mid-Atlantic... Within large-scale upper troughing encompassing much of the central/eastern CONUS, an embedded mid-level shortwave trough over the OH Valley will move eastward across the Mid-Atlantic today. A related weak surface low is also expected to develop eastward across MD/DE/southern NJ this afternoon. While low-level moisture ahead of these features should remain modest over land (generally low to mid 50s surface dewpoints), an effective warm front is forecast to extend from the surface low across eastern PA into NJ. Thunderstorms may initiate along/near this boundary by 16-18Z, with weak instability expected to develop as filtered daytime heating occurs. Stronger flow associated with a mid-level jet will tend to remain displaced to the south of the coastal Mid-Atlantic through the day, but veering winds with height through mid-levels will still support around 25-40 kt of deep-layer shear. Given cold mid-level temperatures (around -20 to -22 C at 500 mb) and modestly steepened lapse rates aloft, any of the stronger cells that develop could produce severe hail. Isolated damaging winds also appear possible as this convection spreads from eastern PA into NJ and vicinity before moving offshore. Low-level winds and related shear should remain fairly modest, but a somewhat more favorable zone for a tornado may exist if a persistent supercell can interact with/cross the surface warm front this afternoon across eastern PA into NJ. The northern extent of the severe risk will likely remain constrained by the warm front, and it still appears likely that appreciable severe risk will tend to remain offshore/south of Long Island and southern New England. ..Gleason/Wendt.. 11/12/2026 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z