Late-Season Severe Wx Outbreak

Ophelia's got some competition tonight in weather news -- it seems we have a late-season severe weather outbreak on our hands. The government has issued a Moderate Risk for Severe Storms in parts of the Northern Plains, and you'd better look out because veteran storm chaser* Roger Edwards wrote that forecast.

Roughly in this area, the government's Storm Prediction Center is calling for a 5% chance of a tornado (doesn't sound like much but this is actually pretty rare), a 25% chance of severe wind gusts, and a 35% chance of severe hail.

*Roger would object to the term "storm chaser" but rather use "storm observer", which I respect. I only use the former term because of its familiarity to the reader.

AccuWeather.com Premium's Henry Margusity says: "I expect severe storms to develop along the cold front across Nebraska this evening and move into Iowa tonight. The storms will be supercell in nature with damaging winds and large hail the main threat."

At 7:15 Central time tonight, AccuWeather.com Professional's National Storm Table showed hail of up to 2.5" in diameter detected on the Sioux Falls radar, along with one TVS (Tornadic Vortex Signature).

About 20 mesocyclones were detected in the Northern Plains. The government's National Weather Service in Sioux Falls has issued several Tornado Warnings this evening, saying in the last one: "NUMEROUS CLOUD ROTATIONS HAVE BEEN REPORTED WITH VARIOUS THUNDERSTORMS."

According to the WeatherMatrix StormMatrix, which gathers government storm reports, one tornado touched down briefly in Valley County, Nebraska just before 7:00 and hail to 2.5" had been confirmed by spotters near Erwin, SD an hour earlier.