A number of convective clusters formed across a moist and moderately sheared airmass on May 23 and 24. Here are a few examples of ProbSevere v4 output. Please note that reports are valid for the 45 minutes after the image time. In Louisiana, PSv4 initially did an excellent job predicting... Read More
As noted in the SPC discussion, destabilization ahead of a shortwave in the Ohio Valley spawned prolific downburst-producing storms, in an environment characterized by 20-30 kt of shear and strong low-level lapse rates....Ohio Valley into the Mid-Atlantic and Southern New England... On the southern fringe of upper troughing over eastern... Read More
Two areas of focus came into view for severe weather this day. One in the Midwest, and one on the Great Plains. You can see both in the SPC’s outlook and verification graphic.In the Midwest, a mesoscale convective system from the previous night was traversing the middle of the country,... Read More
Hail, wind, and tornado hazards were plentiful over the weekend, with numerous opportunities to look at ProbSevere V4. We’ll take a quick look at a few areas.Eastern ColoradoA power supercell was moving east-southeast towards Kansas. There were no tornadoes reported, but numerous wind and hail reports. The ProbSevere probabilities of... Read More
May 13 brought a cold front to the Northeast U.S. and a potent shortwave to the Northwest U.S. It was a good day to test ProbSevere v4 for very different regimes. Here was the SPC’s 12Z synopsis discussion for both regions:... Portions of the Great Basin and the Central and... Read More
The severity of convective lines with low total lightning activity (generally < 5 fl/min) can be difficult to predict, especially prior to the onset of severe hazards being produced. They’re difficult to predict in part because there aren’t often regions that stick out. Cores of storms tend to blend in... Read More
May the 4th was pretty much a mild-mannered hail/wind risk day for early May. Nevertheless, there were some interesting cases from ProbSevere v4. Below are how the SPC outlooks verified for hail and wind.First, near Detroit, Michigan, there was a small broken line segment of cells in a bowing pattern.... Read More
A multi-day severe-weather outbreak occurred this week in the Southern Plains and Mid/Lower-Missippi Valley. Climatologically, this severe weather is right on schedule.Let’s look at ProbSevere v4 for three consecutive days.April 26, 2026The model did a nice job leading convection in Kansas and Missouri, and even in southeast Missouri where there... Read More
Scientists at CIMSS and NOAA/NSSL have been working on what we are calling ProbSevere v4. The goals are the same as previous version of ProbSevere: short-term prediction of severe convective hazards (large hail, damaging wind gusts, and tornadoes). The approach is very different. ProbSevere v4 does not use storm-object identification... Read More
