SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0739 PM CDT Mon Jun 23 2025 Valid 240100Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER TO MID MISSOURI VALLEY NORTHEASTWARD INTO THE GREAT LAKES... ...SUMMARY... Isolated severe wind gusts will be possible this evening from the southern and central Plains northeastward into the Great Lakes. A few severe gusts will also be possible in parts of northern Maine. ...Great Lakes/Mid to Upper Mississippi Valley/Lower to Mid Missouri Valley/ Southern and Central Plains... A large mid-level anticyclone is in place over much of the eastern U.S. today, with southwest mid-level flow over the central states. At the surface, a cold front is located from north-central Kansas northeastward to southern Wisconsin.. Scattered thunderstorms are ongoing near the front. Surface dewpoints ahead of the front are mostly in the 70s F, which is contributing to a southwest-to-northeast corridor of moderate instability. The RAP currently is estimating MLCAPE along this corridor in the 2000 to 3500 J/kg range. Along the instability axis, RAP forecast soundings and regional 00Z soundings suggest that 0-3 km lapse rates are in the 7 to 7.5 C/km range. This should support a potential for isolated severe wind gusts, associated with the more intense multicell line segments. The severe threat is expected to persist for a few more hours. Further southwest into the southern and central High Plains, scattered thunderstorms are ongoing. A moist airmass is present across much of the region, with surface dewpoints generally in the 60s F. The latest RAP has MLCAPE in the 1000 to 2000 J/kg range in most areas. This, combined with steep low to mid-level lapse rates, will support a marginal threat for severe gusts early this evening. ...Northern Maine... On water vapor imagery, flow is west-northwesterly across much of the Northeast, with a subtle shortwave trough moving through the flow. Associated with the trough, a line of thunderstorms is ongoing in southern Quebec. This line will move east-southeastward across central and northern Maine this evening. Ahead of the line, surface dewpoints are in the upper 60s and lower 70s F, which is contributing to weak instability. In addition, RAP forecast soundings across northern Maine early this evening, have some directional shear in the low-levels, with 25 to 35 knots of mid-level flow. This may be enough for a few marginally severe wind gusts along the leading edge of the line during the early to mid evening. ..Broyles.. 06/24/2025
