SPC High Risk

On this date in 1998, the only known high risk outlook for the Northeast was issued. A derecho left a swath of wind damage across the Great Lakes, while more discrete storms on the southwestern flank of the system produced destructive tornadoes.

Over the last decade, the US averages 3-4 high-risk worthy tornado outbreaks per year.

There is a high risk of severe thunderstorms today across parts of northeast Arkansas, far southeast Missouri, far southern Illinois, western Kentucky western Tennessee and extreme northwest Mississippi.

The last year to feature two high risks in the same calendar month in Oklahoma was May 2010, on the 10th and 19th.

The last High Risk outlook in the month of May that included portions of Iowa was issued on May 29th, 2008.

The last High Risk outlook issued for parts of Minnesota was on June 5th, 2008.

A day 1 moderate risk has been issued by SPC: “A regional outbreak of severe thunderstorms is expected across the central Great Plains this afternoon through tonight. The greatest tornado threat, including the potential for strong tornadoes, is expected between 5 to 11 PM CDT.”

On this date in 2011, a high risk outlook was issued for much of Oklahoma and adjacent areas. Clusters of significant tornadoes occurred in western/central Kansas, Oklahoma and North Texas.

On this date two years ago, a high risk outlook with 45% tornado probabilities was issued, centered on western Oklahoma.

On this date in 2010, a high risk outlook was issued, centered on central Oklahoma. Several tornadoes were observed across the state.

On this date in 2014, an upgrade to high risk was introduced with the afternoon day 1 convective outlook. A tornado outbreak was underway across Mississippi and progressing east/northeast.

Ten years today, a widespread tornado outbreak impacted the Tennessee Valley/Southeast and a large swath along and immediately east of the Appalachians mountains.

On this date in 2011, a categorical upgrade to high risk was introduced in the 1630z day 1 convective outlook for portions of eastern North Carolina (and a small part of SC). The high risk was later expanded into parts of adjacent Virginia, as a tornado outbreak was underway.

On this date in 2012, an outbreak of long-track, tornadic supercells occurred across the heart of the Great Plains. A broad high risk outlook issued that morning:

At this hour, 9 years ago, a double barreled day 2 high risk outlook was issued.

SPC maintains day 1 high risk for portions of northeastern Mississippi, northwestern Alabama and southern Tennessee, where a tornado outbreak is expected. There is a threat for a few long-track, violent tornadoes, via @SkyPixWeather/@WxLiz at @NWSSPC

There is a high risk of severe thunderstorms today across portions of central, eastern and northern Mississippi, into northwestern Alabama and southern Tennessee. A tornado outbreak is expected with several strong, long track tornadoes.

The only high risk issued with the initial day 2 outlook for an event was the outlook issued for April 14th, 2012 by Chris Broyles at 0602z on 4/13/12. The only other day 2 high risk wasn’t issued until 1735z on 4/6/06, also by Broyles.

The day 1 high risk area has been expanded east to include more of central Alabama. The high risk, driven by 30% significant tornado probabilities, also includes central Mississippi and small portions of northeastern Louisiana and far southeastern Arkansas.

“If these trends are maintained, an upgrade to a high risk could be necessary with the initial day 1 convective outlook at 06z tonight,” says @WxLiz