Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0732 AM CDT Mon Mar 30 2026 Valid 301300Z - 311200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MIDDLE AND UPPER MISSISSIPPI VALLEY... ...SUMMARY... A few severe thunderstorms with large hail, are expected across parts of the middle and upper Mississippi River Valley tonight through early Tuesday morning. Isolated strong to marginally severe storms could occur further east into parts of Lower Michigan early Tuesday morning as well as over the Texas South Plains this afternoon and evening. ...Synopsis... Early-morning satellite imagery shows a relatively zonal pattern in places across the majority of the CONUS. The only exception is across the Gulf Coast, which is along the northern periphery of modest subtropical ridging. Recent surface analysis shows a broad area of low pressure across the central High Plains/central Plains with several embedded lows, including one over southwest SD, another over south-central NE, and another near the OK/KS/CO border intersection. Modest troughing extends between these features, while a stationary front extends from the southwest SD low east-northeastward across southern MN and central WI. At 11Z, mid 50s dewpoints extended from south-central OK into the Mid-South, with 60s dewpoints farther so from central TX into the Lower MS Valley. Overall upper pattern is expected to remain predominantly zonal throughout the period as a low-amplitude shortwave trough moves along the US/Canada border, accompanied by a strengthening jet streak. Substantial low-level moisture advection is expected throughout the day from the southern Plains/Lower MS Valley into the Mid MS and OH Valleys and Lower MI. By early tomorrow morning, mid 50s dewpoints will likely extend from southern WI across Lower MI and into the upper OH Valley, demarcating a developing warm front. Primary area of thunderstorm development anticipated today is in the vicinity of the developing warm front from the mid/upper MS Valley across the Lower Great Lakes into the Upper OH Valley and Northeast. Isolated thunderstorms are also possible with the moist and confluent environments of the FL Peninsula and the Lower MS Valley as well as along the dryline in the southern High Plains and seasonably moist airmass over the Southwest. ....Mid/Upper MS Valley into Lower MI and the Upper OH Valley... Significant low-level moisture advection is expected throughout the day into Mid MS Valley, although this advection will be offset somewhat by strong heating and deep boundary-layer mixing. General expectation is that upper 50s dewpoints will reach the IA/MO/central IL vicinity by 00Z, with mid 50s farther north into southern WI and southern Lower MI. Given negligible large-scale forcing and strong mixing, capping is expected prevail throughout the day and into the early evening. However, beginning around 22-00Z, increasing mid-level moisture coupled with continued low-level moisture advection and convergence near a weak surface low could result in convective initiation across central IA. The earliest development could be surface based with a trend towards more elevated storms with time and northeastward extent as warm-air advection increase during the evening. Steep lapse rates and moderate shear support the potential for supercells with any more sustained updrafts. Large to isolated very large hail is the primary severe risk. Even with the elevated storm character, the prevailing warm/dry conditions above the shallow return moisture could support strong downdrafts with strong surface gusts. Farther east, a few instances of small hail are possible from western PA into western NY with the thunderstorms expected during the evening and overnight. ...Southern High Plains... Isolated thunderstorm development is possible along a dryline forecast to extend from a weak low in western KS southwestward into the TX Trans Pecos. Buoyancy will be weak and vertical shear modest so storm structures are not expected to be particularly robust or long lived. However, high cloud bases and steep low-level lapse rates could still support a few stronger gusts at the surface. ..Mosier/Marsh.. 03/30/2026Read more
