Day 4-8 Convective Outlook
Issued: · Valid: –
Summary
Scattered thunderstorms with the potential for severe gusts are expected across the Appalachians and Northeast on Saturday, with additional storms potentially becoming severe in parts of eastern Nebraska, Iowa, and Missouri during the evening. Mid-Atlantic thunderstorms with strong gusts may occur Sunday, followed by a possibility of damaging wind corridors stretching from the upper Mississippi Valley toward the Northeast early next week.
Product Text
000 ACUS48 KWNS 050902 SWOD48 SPC AC 050900 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CDT Wed Aug 05 2026 Valid 081200Z - 131200Z ...DISCUSSION... ...Saturday/D4... Southwest midlevel winds of only 25 kt will exist across the Northeast, while low-level moisture remains in place supporting up to 2000 J/kg MUCAPE with poor lapse rates aloft. This will support daytime thunderstorms over a large area from the Appalachians into the Northeast, and a few severe gusts cannot be ruled out. Otherwise, normal gusty outflow winds are to be expected. To the west, an area of stronger instability is forecast across the Mid MO Valley, where northwesterly midlevel winds of 35 kt will exist along the southern periphery of a trough sweeping across the Upper Great Lakes. Evening/overnight storms may occur across parts of eastern NE, IA, and MO, and instability may be large enough to warrant at least low severe probabilities as the event nears in time. ...Sunday/D5... Drying will occur aloft over parts of the Northeast as a wave moves into Quebec, but substantial low-level moisture will still support scattered thunderstorms ahead of a cold front across the Mid Atlantic. Shear will again be weak, but perhaps enough mean wind speeds will exist for storms to be mobile/produce areas of strong gusts. To the west, low-level moisture is forecast to shift a bit farther north into the Dakotas, and this will occur beneath stronger northwest flow aloft. This area bears watching in later outlooks, as wind profiles may somewhat favor supercells. Predictability is currently low. ...Mon/D6 to Wed/D8... While predictability decreases further during this time frame, moderate west to northwest flow aloft will remain from the upper MS Valley across the Great Lakes, which will spread into the Northeast D7/D8. If a wave does amplify within this flow regime, a corridor of damaging winds could develop given upper 60s to low 70s F dewpoints along/south of the mean frontal zone (roughly IA to NY/PA by end of the period). Model variation is currently too great to depict an precise corridor. ..Jewell.. 08/05/2026