Subj : DAY1 3/5 RISK AREA UPDAT To : All From : Dumas Walker Date : Wed Jul 01 2026 23:08:00 ACUS01 KWNS 012007 SWODY1 SPC AC 012006 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0306 PM CDT Wed Jul 01 2026 Valid 012000Z - 021200Z ....THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE UPPER MIDWEST INTO THE GREAT LAKES... ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHEAST...CENTRAL HIGH PLAINS...AND GULF COAST STATES... ....SUMMARY... Multiple rounds of severe thunderstorms are still expected across the Upper Midwest and Upper Great Lakes into tonight. A couple of tornadoes are possible but damaging wind gusts are expected to be the more widespread hazard, in addition to isolated large to very large hail. Severe storms also remain a concern across parts of the central High Plains, Northeast, and Southeast/Tennessee Valley. ....20Z Update... The main change made to this outlook was to expand the wind-driven severe probabilities southward across portions of the Upper Midwest based on observational trends. A belt of relatively thick cloud cover exists across portions of the Midwest. However, considerable clearing and a CU field, along with isolated thunderstorms, has developed across eastern IA into southern WI, where appreciable buoyancy (2000-3000 J/kg MLCAPE) and up to 40 kts of effective bulk shear reside. Furthermore, a few of the latest WoFS runs also depict some higher thunderstorm coverage across eastern IA into southern WI. As such, the thinking is that organized severe potential, mainly in the form of severe gusts, should exist across this region through the evening. Otherwise, the previous forecast remains on track, with relatively minor changes made to the thunder and severe probabilities to reflect the latest observations and guidance consensus. ...Squitieri.. 07/01/2026 ..PREV DISCUSSION... /ISSUED 1156 AM CDT Wed Jul 01 2026/ ....Midwest and Upper Great Lakes... An active multi-round day of severe weather is expected across the region through tonight. Early this afternoon, ongoing severe risks will continue to focus across northern Michigan as well as eastern Wisconsin, with a secondary round of severe storms potentially spreading into Lower Michigan later this afternoon. See existing Mesoscale Discussions/Watches for short-term details. Severe potential later today will focus on a convectively reinforced boundary, with a very moist and potentially unstable environment along and south of it. Renewed deep convective development is expected later this afternoon into tonight across northern Iowa and southern Minnesota, and again into Wisconsin. A ribbon of moderately strong mid-level westerlies, some of it MCV-enhanced, will support organized storm modes including supercells and fast-moving line segments and potential upscale-MCS development. Large to very large hail will be possible with the more intense storms in addition to wind, which may become more prevalent of a hazard (60-80+ mph) as storm mergers lead to a couple of strong to severe clusters developing. Some tornado potential may exist as well, particularly along the effective boundary and/or increasing this evening as a southwesterly low-level reinvigorates. ....Central and southern High Plains... High-based thunderstorm development is expected along a north/south-oriented lee trough/dryline during the afternoon and evening. Despite modest deep-layer shear (around 25-30 kt), steep low/mid-level lapse rates will contribute to a strongly unstable airmass. A mix of loosely organized clusters and possibly some supercell structures will be capable of producing severe wind gusts and large hail. Farther south into the southern High Plains, weaker flow will limit overall storm organization, but steep lapse rates will support severe gusts with the more intense downdrafts. ....Northeast... Enhanced west-northwesterly mid-level flow will persist across the Northeast, where a warm/moist air mass will contribute to around 3000 J/kg MLCAPE, especially across much of New York and Pennsylvania. While nebulous mesoscale forcing for ascent casts uncertainty on overall convective coverage and evolution, the strong buoyancy and a veering wind profile (albeit modest deep-layer shear quantitatively) will favor east-southeastward-spreading convection capable of damaging wind gusts and isolated hail during the afternoon, and again during the evening/nighttime hours. ....Southeast/Tennessee Valley... Along the southern periphery of a mid-level anticyclone centered over the central Appalachians, easterly flow through much of the troposphere resides atop a hot/moist air mass with 3000-4000 J/kg MLCAPE this afternoon. 12z observed soundings from Atlanta, Birmingham, and Jackson MS notably sampled 25-35 kt winds between 3-6km AGL, which could aid in storm organization this afternoon. A somewhat cooler thermal profile aloft was also noted with the 12z Atlanta sounding with a relatively steep mid-level lapse rate profile. Strong to severe pulse thunderstorms are expected regionally, and seemingly with a somewhat greater coverage and likelihood than a typical pulse-type scenario. The stronger water-loaded wet microbursts will yield localized gusts of 50-65 mph and be capable of wind damage. ....Montana and northern Great Basin... Isolated to widely scattered thunderstorms are expected ahead of a slow-moving mid-level trough moving across the Northwest. Preceding the trough, around 40 kt of mid-level southwesterly flow and a weakly unstable air mass will support a couple loosely organized clusters capable of producing severe wind gusts during the afternoon and evening. $$ --- Scorpio BBS * Origin: (618:250/10) .