November 17, 2013 Tornado Outbreak

Fast Facts

• This event had just over 70 tornadoes across seven states - Illinois, Missouri, Kentucky, Tennessee, Indiana, Michigan, and Ohio.  Illinois and Indiana had 55 of these tornadoes.
• There were 25 tornadoes in Illinois identified, with 14 being significant (EF-2 or stronger).  Of these, two were EF-4 and three were EF-3.  For a complete listing, see this list from NWS Lincoln, IL.
• This ranked as the 4th largest outbreak for the state of Illinois, in terms of number of tornadoes, since 1950.  (list complied by NWS Lincoln)
• There were 30 tornadoes in Indiana identified, which ranks this event as the second largest number of tornadoes in one day in state history. (reference)
• One supercell in Illinois produced five tornadoes, which were the ones to impact Pekin, Washington, Dana, Coal City, Manhattan, and Frankfort. 
• The EF-4 tornado with maximum estimated winds of 190 mph that struck Washington, IL was the strongest on record for Illinois in the month of November since 1950.  (reference)
• 101 tornado warnings were issued for Illinois by the National Weather Service on November 17.

Storm Reports

Storm Reports	Midwest Storm Reports

National Storm Reports       |       Local Storm Reports (PDF)

Tornadoes

The first map (tornado outbreak map) is of locations where tornado damage occurred based on NWS storm surveys.  Note that each report does not reflect a different tornado, with many reports clustered together or strung out in a path being caused from the same tornado.

Tornado Outbreak Map	Local Tornado Track Map	Illinois Tornado List

Tornado Damage Survey Results (PDF)
 

Fourth Largest Outbreak Tornadoes in Illinois

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
420 PM CST WED DEC 4 2013 /520 PM EST WED DEC 4 2013/

...NOVEMBER 17TH TORNADO OUTBREAK CONFIRMED AS FOURTH LARGEST FOR
ILLINOIS..

THE SIGNIFICANT TORNADO OUTBREAK ON NOVEMBER 17TH SAW AT LEAST
70 TORNADOES IMPACT SEVEN STATES. THIS INCLUDES 25 TORNADOES
CONFIRMED IN ILLINOIS. SINCE 1950...WHICH BEGAN THE ERA OF MORE
DETAILED TORNADO DOCUMENTATION...THE 25 TORNADOES RANKS AS THE FOURTH
HIGHEST IN ILLINOIS DURING A SINGLE EVENT.

RANK    NUMBER OF IL TORNADOES      DATE(S)
-----------------------------------------------
1.                41                4/19/1996
2.                36                4/2/2006
3.                26                4/7/1998
4.                25                11/17/2013
5.                22                5/18/2000

WHEN LOOKING AT TORNADO CLIMATOLOGY IT IS ALWAYS IMPORTANT TO
NOTE THAT THE NUMBER OF REPORTED WEAKER TORNADOES (EF-0 TO EF-1)
ACROSS THE NATION SAW A SHARP INCREASE IN THE 1990S. MUCH OF THIS
INCREASE IS EXPLAINED BY...1.) THE INSTALLATION OF DOPPLER RADAR
ALLOWING FOR BETTER DETECTION OF POTENTIAL AREAS OF TORNADO
OCCURRENCE FOR FOLLOW-UP SURVEYS...2.) AN INCREASE IN SKYWARN
SPOTTER TRAINING AND JUST THE OVERALL NUMBER OF SPOTTERS
AND...3.) ABILITY FOR MORE REGULAR AND THOROUGH NWS STORM DAMAGE
SURVEYS.

WHAT CAN EVEN FURTHER PUT THIS INTO HISTORICAL CONTEXT IS THE
NUMBER OF SIGNIFICANT TORNADOES...OR THOSE OF EF-2 MAGNITUDE OR
STRONGER. THESE TORNADOES ACCOUNT FOR A LARGE PERCENTAGE OF OVERALL
TORNADO FATALITIES AND INJURIES AS WELL AS DAMAGE. NOVEMBER 17TH SAW
14 OF THESE EF-2 OR STRONGER TORNADOES IN ILLINOIS. THAT RANKS AS
ONE OF THE HIGHEST NUMBER IN ANY EVENT SEEN IN ILLINOIS SINCE
1950...AND IN FACT STANDS AS SECOND ONLY BEHIND DECEMBER 18TH
1957...WHICH SAW 17 SIGNIFICANT TORNADOES (AND 19 TOTAL
TORNADOES).

THE NUMBER OF EF-2 OR STRONGER TORNADOES OVER TIME IS MUCH LESS
SUSCEPTIBLE TO THE AFOREMENTIONED FACTORS THAT HAVE LED TO A SPIKE
IN THE EF-0 AND EF-1 TORNADOES OVER TIME. THE FACT THAT NOVEMBER 17TH
SAW 14 OF THESE TORNADOES REFLECTS JUST HOW POTENT OF AN EVENT IT
WAS...AS WELL AS HOW MUCH MORE IT COULD HAVE BEEN HAD THE SIGNIFICANT
TORNADOES IMPACTED EVEN MORE DENSELY POPULATED AREAS.

MUCH THANKS GOES TO OUR COLLEAGUES AT WFO LINCOLN FOR HELP IN
DETERMINING THE TORNADO NUMBERS FOR NOVEMBER 17TH AND WHERE IT
STACKED UP COMPARED TO PAST EVENTS.

$$

MTF

Radar

Reflectivity 10:30 am - 2:00 pm	Supercell-Centric Reflectivity View, 10:30 am - 1:10 pm	Long-Lived Supercell Track
This loop is from the NWS Lincoln and Chicago Radars, 0.5° Reflectivity	This loop is the same as the left, but centered on the long-lived supercell that likely produced multiple tornadoes from the Pekin and Washington areas northeast in the Dana area and across Grundy and Will Counties.	Here is a map of the first two tornadoes produced from this supercell.

Environment 

   While severe thunderstorms are extremely complex, the ingredients they need to develop come down to a few simple ones:  1.)  warmth and moisture, which create instability  2.)  strong turning winds with height, creating wind shear and 3.) a focus such as a cold front. The stronger these parameters are, especially wind shear, the greater potential for tornadoes. 

    In November, the environmental winds tend to be much stronger than in summer or even spring months.  This leads to even greater wind shear.  Normally though in late autumn and into winter, we do not have sufficient warmth and moisture for thunderstorm development.  A powerful low pressure system across the plains states had steered warmth and moisture northward for nearly two days, with moisture similar to summertime values (dew points in the mid 60s).  Given temperatures of around 70°, there was more than enough instability to get thunderstorms to go.  And this instability was actually off the charts for November.  Combine that with the high wind shear, and a cold front sweeping eastward, and you had all the ingredients you needed for thunderstorms, particularly supercells capable of tornadoes.  With the parameters all extremely high for any time of the year, long-lived significant tornadoes became likely.

Do Tornadoes Happen Here in November?

   
Below is listed the tornadoes that have occurred across the NWS Chicago CWA since 1950 prior to November 17, 2013.  There had been a total of 12 before Sunday, in a total of six events (basically one such event every decade).  Note that eight of the November tornadoes have been EF-2 or stronger, showing that when tornadoes do occur in November, there is a decent likelihood they will be significant (EF-2 or stronger).  The primary reason for this is strong dynamics and wind field that tend to be present in the cool season (late autumn and winter), which add to a greater amount of wind shear.  This is a key component to tornadoes, and the greater the wind shear the more likelihood for significant tornadoes.

November tornadoes to occur in the NWS Chicago CWA since 1950: 

Illinois tornadoes in November

The greatest number of significant tornadoes (F2 or greater) in a November outbreak was seven F2 tornadoes on November 12, 1965.

Late Autumn Tornado Events in the Region:

• November 22, 2010:  Caledonia, IL
• October 26, 2010:  Four tornadoes across the area
• November 10, 2002:  Northern Indiana Into Ohio Outbreak

Forecast Service

Warnings

NWS Tornado Warnings Issued on November 17, 2013
National	Zoomed-In

PUBLIC INFORMATION STATEMENT
NATIONAL WEATHER SERVICE CHICAGO IL
757 AM CST MON NOV 18 2013 /857 AM EST MON NOV 18 2013/

...INTERESTING NOVEMBER TORNADO TRIVIA FOR ILLINOIS...

A RARE NOVEMBER OUTBREAK OF TORNADOES OCCURRED IN ILLINOIS ON
SUNDAY NOVEMBER 17TH. SURVEY TEAMS FROM NATIONAL WEATHER SERVICE
OFFICES ACROSS THE STATE WILL BE OUT SURVEYING THE DAMAGE TODAY
WITH SOME RESULTS OF THESE SURVEYS AVAILABLE LATER TODAY. COLLEGE
OF DUPAGE METEOROLOGY PROFESSOR VICTOR GENSINI FOUND THE FOLLOWING
INTERESTING STATISTICS.

INCLUDING YESTERDAY...THERE HAVE BEEN 194 TORNADO WARNINGS ISSUED
IN THE MONTH OF NOVEMBER IN ILLINOIS DATING BACK TO 1986. OF
THOSE 194...101 OR 52 PERCENT WERE ISSUED DURING SUNDAYS TORNADO
OUTBREAK.

PRIOR TO YESTERDAY...LOOKING BACK TO 1950 THE STRONGEST NOVEMBER
TORNADO IN ILLINOIS WAS AN F-3. THAT OCCURRED EAST OF ST LOUIS
BACK ON NOVEMBER 15 1988. PRELIMINARY FINDINGS FROM THE NATIONAL
WEATHER SERVICE ST. LOUIS INDICATE THAT ONE OF THE TORNADOES
DOWNSTATE YESTERDAY WAS AN EF-4. IF THIS RATING BECOMES FINAL THEN
YESTERDAY`S TORNADO OUTBREAK WILL HAVE PRODUCED THE STRONGEST
ILLINOIS TORNADO IN NOVEMBER DATING BACK TO 1950.


$$

IZZI

Other Areas Impacted