Day 4-8 Convective Outlook
Issued: · Valid: –
Summary
Isolated severe thunderstorms are possible across parts of eastern Kansas, Missouri, the central High Plains, and southeast Arizona on Wednesday afternoon and evening. A severe weather threat may also develop across the Mid-Atlantic and Northeast from Thursday through Sunday.
Product Text
000 ACUS48 KWNS 020829 SWOD48 SPC AC 020828 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0328 AM CDT Sun Aug 02 2026 Valid 051200Z - 101200Z ...DISCUSSION... ...Day 4/Wednesday... Broad troughing will exist from Hudson Bay into the north-central U.S. with a belt of enhanced, cyclonic flow from the northern Rockies through northern and central Plains into the upper Great Lakes. At the surface, a front will advance through the upper Great Lakes with the western extension of the boundary settling more slowly south through the central into southern High Plains. Thunderstorms may be ongoing at 12Z across portions of the mid MO Valley with lingering clouds and convective outflow potentially modulating the location of the effective surface front and the degree of instability ahead of it. The models suggest an area from eastern KS into MO as being the most probable location for at least isolated severe storms during the afternoon and evening hours. The extent of the threat will likely be dependent on mesoscale details yet to be known. As such, no area will be delineated in this forecast. Other areas of isolated severe storm potential will be in the central High Plains and southeast AZ. ...Days 5 and 6/ Thursday and Friday... A slight eastward shift of the mean trough position is forecast on Thursday with some model signal for an embedded short-wave trough to move through the Great Lakes. At the surface, there is some suggestion that a weak front or wind shift will move into the northern Mid-Atlantic during the afternoon with the trailing extension of that boundary stretching through the mid MS Valley into the southern High Plains. Ahead of that boundary, widespread 70+ F dewpoints are expected from New England into the Mid-Atlantic and Carolinas, leading to moderate to potentially strong instability. The greatest potential for a few severe storms appears to be across the Mid-Atlantic Thursday afternoon where the moderate instability will coincide with a belt of 30-40 kt mid-level flow. Some severe weather threat may also develop in the Ozark Plateau and AZ Thursday afternoon and evening. On Friday, the above-mentioned Great Lakes short-wave trough is expected to shear northeast across southern ON with 30-40 kt of mid-level flow prevailing over the Northeast. The surface pattern is somewhat disorganized with some semblance of a trough from southern New England through the Mid-Atlantic coastal region. Moderate to strong instability may again develop ahead of that feature, supporting the potential for some severe weather threat during the afternoon and early evening hours. However, the strongest vertical shear is forecast to remain to the north of the stronger instability, leading to uncertainty in the magnitude of the severe threat. ...Days 7 and 8/Saturday and Sunday... The various 00Z ensemble mean solutions indicate a slight eastward shift of an upper low near Hudson Bay with low-amplitude troughing and strengthening mid-level flow moving into the Northeast. Southerly low-level winds within the western periphery of a surface high positioned off the Atlantic Coast will maintain a moist and unstable air mass beneath the strengthening winds aloft. As such, some severe weather threat is expected to persist from the Mid-Atlantic into New England this period. Elsewhere, there is some model signal for a surface front to move into the Midwest, where some severe weather potential may exist. ..Mead.. 08/02/2026