SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1212 PM CDT Sat Oct 18 2025 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL APPALACHIANS TO THE MID-ATLANTIC...AND ACROSS PARTS OF THE GULF COAST... ...SUMMARY... Isolated wind damage may occur on Sunday into early Monday from parts of the central Appalachians to the Mid Atlantic coastal regions. Additional isolated severe storms are possible over the Gulf Coast early Sunday. ...Synopsis... An upper trough over the MS Valley will shift east/northeast on Sunday, overspreading much of the Midwest and TN Valley, and becoming oriented from western NY to the Mid-Atlantic coast by Monday morning. Strong flow aloft, with an 80-100 kt 500 mb jet streak will overspread portions of the central Appalachians to the Mid-Atlantic coast. Around 40-50 kt 850 mb south/southwesterly flow also is expected to spread east from the Gulf Coast and Ohio Valley to the Atlantic coast through the period. At the surface, the primary cyclone over Lower MI will lift northeast into Ontario and Quebec, with a trailing surface trough and cold front extending southward to the central Gulf Coast. The front will develop east/southeast, and move offshore the Atlantic coast by the end of the period, with the southern extent of the front arcing southwestward into the northern FL Peninsula. Richer boundary layer moisture will remain confined to the Gulf Coast/Southeast states though peak heating, with some greater northward moisture transport into the Mid-Atlantic coast after 00z. ...Central Appalachians to Mid-Atlantic... Boundary layer moisture will remain limited, with dewpoints generally only reaching into the 50s, with some 60s possible closer the Chesapeake Bay and Mid-Atlantic coast vicinity during the evening/overnight. Poor low/mid-level lapse rate also are forecast, largely limiting instability to less than 400 J/kg MLCAPE. Furthermore, convection developing along the eastward-advancing cold front will be low-topped, generally below 3 km deep. Nevertheless, convective showers could enhance surface gusts given 40-50 kt flow in the 850-700 mb layer. Isolated gusts 50-60 mph will be possible with stronger convective elements. ...Gulf Coast... Strong to isolated severe storms are likely to be ongoing Sunday morning across AL and the western FL Panhandle near the eastward-progressing surface cold front and within a 40-50 kt 850 mb low-level jet lifting to the northeast. Strong gusts and perhaps a tornado will be possible with storms through around midday/early afternoon. Thereafter, large-scale ascent will become increasing displaced to the northeast. Vertical shear and thermodynamic profiles become less favorable with eastward extent across GA and northern FL as well, limiting the eastward extent of the severe risk. ..Leitman.. 10/18/2025
