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

SPC AC 120521 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 PM CST Wed Nov 11 2026 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS TODAY ACROSS PARTS OF SOUTHEASTERN PENNSYLVANIA...MUCH OF DELAWARE...ADJACENT EASTERN MARYLAND AND SOUTHERN THROUGH CENTRAL NEW JERSEY... ...SUMMARY... A couple of strong thunderstorms, accompanied by at least some risk for severe weather, may impact parts of the northern Mid Atlantic this afternoon. ...Discussion... Downstream of amplified mid-level ridging, which may have reached peak amplitude across the U.S. Intermountain West and Rockies through much of the Canadian Prairies, a number of digging short wave perturbations are forecast to contribute to the evolution of a more prominent, positively tilted mid-level trough. This may encompass most areas near and east of the Mississippi River through the Atlantic Seaboard by 12Z Friday. One leading short wave trough is generally forecast to turn east and northeast of the Allegheny/Cumberland Plateau through the northern Mid Atlantic by late this afternoon, before undergoing considerable deformation as it progresses farther to the northeast. It appears that this may be accompanied by an initially modest surface cyclone, which may undergo notable deepening during the day while redeveloping to the east-northeast of the Blue Ridge, before occluding across the northern Mid Atlantic this evening. ...Northern Mid Atlantic... Low-level moisture return inland of the coast appears likely to be rather limited. However, boundary-layer dew points increasing through the lower/mid 50s F, within a corridor along a warm frontal zone to the east of the surface low, may be sufficient to yield mixed-layer CAPE in excess of 500 J/kg when coupled with mid-level cooling (including 500 mb temperatures of -20 to -22 C). Based on forecast soundings, this may include buoyancy rooted near and just off the surface, as low-level lapse rates steepen beneath the cold air and boundary-layer humidity remains relatively high along the frontal zone. Although low-level hodographs might not become more than modestly large, in the presence of moderate deep-layer shear, it appears at least possible that the environment could become conducive to the evolution of one or two supercell structures posing some risk for a tornado. Otherwise, stronger cells this afternoon may be accompanied by small to perhaps marginally severe hail and locally strong surface gusts, before weakening by evening. ..Kerr/Chalmers.. 11/12/2026 CLICK TO GET WUUS01 PTSDY1 PRODUCT NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z