A November tornado outbreak for the record books

Dozens of tornadoes touched down in the Midwest and Ohio Valley Sunday, killing eight and destroying hundreds of homes. The outbreak was one of the worst on record during November. The National Weather Service (NWS) issued over 400 severe weather warnings and logged over 600 reports of tornadoes, damaging winds, and/or large hail.

Warnings issued by the National Weather Service (left); reports of tornadoes, damaging winds, and hail (right) (National Weather Service)

Warnings issued by the National Weather Service (left); reports of tornadoes, damaging winds, and hail (right) (National Weather Service)

The most devastating tornado occurred in Washington, Illinois, where a tornado – with a preliminary rating of EF-4 (on the 0-5 scale) – damaged or destroyed 250-500 homes, according to the Associated Press. A second EF-4-rated twister touched down in New Minden, Illinois.

A Washington firefighter peers into the home of a fellow firefighter whose home was destroyed when a tornado swept through Washington, Ill., Sunday, Nov. 17, 2013.  (AP Photo/Journal Star, David Zalaznik)  MANDATORY CREDIT

A Washington firefighter peers into the home of a fellow firefighter whose home was destroyed when a tornado swept through Washington, Ill., Sunday, Nov. 17, 2013. (AP Photo/Journal Star, David Zalaznik) MANDATORY CREDIT

Historical perspective

Because the NWS is still evaluating tornado reports from Sunday, a final count of the actual number of tornadoes is not known. The NWS Storm Prediction Center (SPC) logged 81 reports, but some may be duplicates. Nevertheless, Sunday’s outbreak will probably rank among top 5 biggest outbreaks on record for the month.

Here is the current top 5 list (courtesy weather.com), not including Sunday’s outbreak:

5. Nov. 27-28, 2005: 56 tornadoes
4. Nov. 23-24, 2001: 66 tornadoes
3. Nov. 9-11, 2002: 82 tornadoes
2. Nov 23-24, 2004: 93 tornadoes
1. Nov 21-23, 1992: 105 tornadoes

The EF-4 tornadoes that touched down in Washington and New Minden, Ill. are two of only 22 EF-4 or higher tornadoes to occur in November on record. The Washington, Ill. twister is the third most northerly EF-4 to occur on record in November, noted The Weather Channel’s Jim Cantore on Twitter.

The tornadoes are the only two EF-4s to form in Illinois in November in modern records.

Victor Gensini, a professor of meteorology at the College of DuPage, tweeted that of the 194 tornadoes warnings issued in Illinois in 2013, 101 were hoisted Sunday – some 52 percent!

Sunday’s outbreak should rank among the three biggest of 2013. Although the total number of tornadoes this year is well below average, the number of violent tornadoes (EF-4 or higher) is above average, with 9 total, compared to the 30-year average of 7.7.

The cause

A very strong cold front sliced across the central and eastern U.S., clashing with warm, mild air out ahead of it. A strengthening area of low pressure along the front, helped to generate large amounts of low level spin. At high altitudes, an extremely powerful jet stream – roaring along at around 140 mph – energized the storm system.

NAM model shows high altitude winds blow at 120 knots (roughly 140 mph) through the Midwest Sunday afternoon (WeatherBell.com)

NAM model shows high altitude winds blow at 120 knots (roughly 140 mph) through the Midwest Sunday afternoon (WeatherBell.com)

The volatile combination of atmospheric ingredients prompted the National Weather Service Storm Prediction Center to place most of Indiana, eastern Illinois, and western Ohio under a high risk of severe thunderstorms.

This was just the fifth high risk day designated by SPC in November on record (since 1989); the last such issuance was Nov. 15, 2005.

Overview of November "high risk" severe weather days prior to Sunday (National Weather Service/Greg Carbin)

Overview of November “high risk” severe weather days prior to Sunday (National Weather Service/Greg Carbin)

Accurate forecasts

The NWS did an outstanding job identifying the potential for multiple strong, fast-moving tornadoes and highlighting the high risk area. The greatest concentration of tornadoes and damaging wind reports occurred exactly where the NWS predicted.

 

Chicago Bears’ controversy

Despite the forecasts for hazardous weather in Chicago and a dangerous line of thunderstorms approaching the Soldier Field, the NFL did not delay the start of the game between the Chicago Bears and Baltimore Ravens.

Instead, it waited to evacuate fans to concourses until a warning had been issued and a storm was practically on top of the stadium.

No fans were hurt, but the NFL was hit by sharp criticism from meteorologists and some media affiliates.

Damage video and photos

Damage in Washington, Ill. via photographer using Google Glass

 

 

 

 

 

Tornado videos

Additional video available at USTornadoes.com: Videos from the November 17, 2013 tornado outbreak

Deadly storms strike Midwest

(CWG’s Ian Livingston contributed to this post)

Also on Capital Weather Gang

D.C. area forecast: Mild today, seasonably chilly midweek, cold shot to close week