Day 4-8 Convective Outlook
Issued: · Valid: –
Summary
Severe thunderstorms are possible across New England on Tuesday afternoon through the overnight hours, with the potential for all severe hazards. Another period of severe weather with potential damaging outflows and storms is expected from Friday into the following week across the Upper Great Lakes into the Mid-Atlantic.
Product Text
000 ACUS48 KWNS 110902 SWOD48 SPC AC 110900 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CDT Sat Jul 11 2026 Valid 141200Z - 191200Z ...DISCUSSION... Ensemble guidance continues to indicate that the CONUS-wide mid-level ridge centered over the north-central United States will build westward during the upcoming week in response to a series of mid-level troughs moving through central Canada. These troughs will help to carve out a seasonably strong trough across eastern Canada. By the end of the week, the US ridge will be centered over the Rockies with the eastern Canada trough centered over Quebec. The result will be a strong mid-level height gradient (and strong mid-level flow) stretching from the Upper Great Lakes southeast into the Mid-Atlantic and encompassing New England. ... Tuesday/Day 4 -- New England ... Multiple ensemble systems continue to support a favorable severe weather environment being in place across New England on Tuesday. Strong diurnal heating and southwesterly surface flow should allow surface temperatures to warm into the mid-80Fs to perhaps low-90Fs by late afternoon ahead of a seasonably strong surface cold front. Ahead of the cold front, surface dewpoint temperatures should rise into the 60Fs to perhaps 70Fs, leading to MUCAPE between 1000-2000 J/kg. Current thinking is that thunderstorms will develop along and ahead of the surface cold front during the afternoon across Quebec and move into New England during the late afternoon before dissipating overnight. Strong vertical shear in excess of 50 knots will combine with strong instability to support severe thunderstorms. The most probable scenario is for one or more broken lines of storms to move across the region, with perhaps a few embedded supercells. All severe hazards seem possible at this time. ... Friday/Day 7 and Beyond -- Upper Great Lakes into the Mid-Atlantic ... Strong northwest flow will be established between the previously described western US ridge and eastern Canadian trough. Rich boundary layer moisture is expected to be present to the south of a residual cold front that will be draped somewhere from the Great Lakes southeast into the Mid-Atlantic/Southern New England. Strong diurnal heating each afternoon will support scattered thunderstorm development capable of producing damaging outflows. Severe probabilities were introduced for Day 7 with this outlook given increasing confidence in thunderstorms developing within surface troughing east of the Appalachians. The exact location of these highlights will likely be refined with subsequent outlooks. Additionally, the overall large-scale pattern seems conducive for one or more shortwave troughs to move through the broader northwesterly flow across this region. Given the (seasonably) strongly unstable and sheared environment, one or more southeastward moving MCSs may be possible during the Day 7 - Day 10 period. Ensemble guidance varies significantly as to the timing and location of these potential short-wave troughs, but the overall pattern would suggest additional severe weather potential at the end of the forecast period and in the days that follow. ..Marsh.. 07/11/2026