Day 1 Convective Outlook
Issued: · Valid: –
Product Text
000 ACUS01 KWNS 060601 SWODY1 SPC AC 060559 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Sat Jun 06 2026 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER GREAT LAKES...OHIO VALLEY AND NORTHEAST... ...SUMMARY... Thunderstorms with severe wind gusts and isolated large hail are expected to develop today from parts of the lower Great Lakes and Ohio Valley into the Northeast. Large hail and severe wind gusts are also expected in the northern High Plains. Strong wind gusts and hail may also occur in parts of the southern Plains. ...Lower Great Lakes/Ohio Valley/Northeast... An upper-level trough and an associated mid-level jet streak will move eastward into the lower Great Lakes today. A cold front will advance southeastward into the lower Great Lakes, with surface dewpoints ahead of the front in the mid to upper 60s F. An axis of moderate instability appears likely to develop well ahead of the front by early to mid afternoon. As this happens, convective initiation will take place near this axis of instability from northern Indiana eastward into northern Pennsylvania and northeastward into southern New York. Convective coverage will gradually expand, as a broken line segment moves southeastward into the Ohio Valley and toward the coast of the Mid-Atlantic and New England. RAP forecast soundings at 21Z near the instability axis over northern Ohio and southwestern Pennsylvania have 0-6 km shear near 45 knots, which could support supercell development. Supercells will be capable of severe wind gusts, hail and an isolated tornado threat. During the late afternoon, a transition to more linear development is expected, which should result in an increased wind-damage threat. Further east from central Pennsylvania into southern New England, forecast soundings at 21Z have 0-6 km shear in the 25 to 30 knot range with 0-3 km lapse rates between 7.5 and 8 C/km. This environment will support severe storm development. Although an isolated supercell will be possible, the most likely mode will be linear, favoring wind-damage as the primary threat. The potential for severe gusts will be maximized from south-central Pennsylvania northeastward into far southern New York. The line segment is expected to reach the Mid-Atlantic and New England Coasts by early evening. ...Northern High Plains... West-southwesterly mid-level flow over the northern High Plains will become more southwesterly during the day, as an upper-level trough moves through the Pacific Northwest. At the surface, a low will deepen over the northern High Plains, with a trough located northeastward into far northeast Montana. As surface temperatures warm today, moderate instability will develop near the surface trough. This, combined with increasing low-level convergence, will result in scattered convective initiation. Multiple storms are forecast to move northeastward across the northern High Plains during the late afternoon and early evening. RAP forecast soundings near the surface trough in far northeast Montana at 00Z have MLCAPE around 2000 J/kg with 0-6 km shear near 35 knots. Surface-temperature dewpoint spreads are large with low to mid-level lapse rates in the 8 to 9 C/km range. This should be favorable for high-based supercells capable of large hail and severe wind gusts. The severe threat will likely persist into the early to mid evening. ...Southern Plains... A mid-level low will move across west Texas today. At the surface, a moist airmass will be in place over the southern Plains, where dewpoints will be from the upper 60s into the mid 70s F. This will result in the development of moderate instability by afternoon. To the east of the mid-level low, low-level convergence is forecast to become maximized over parts of west-central Texas and southern Oklahoma. As a result, scattered thunderstorms are expected to develop from late afternoon into the evening. The instability combined with steep low-level lapse rates (exceeding 7 C/km) will support an isolated threat for severe wind gusts and hail. ..Broyles/Lyons.. 06/06/2026 $$