Fast Facts
Storm Reports |
Midwest Storm Reports |
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National Storm Reports | Local Storm Reports (PDF)
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 |
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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
Reflectivity 10:30 am - 2:00 pm |
Supercell-Centric Reflectivity View, 10:30 am - 1:10 pm |
Long-Lived Supercell Track |
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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. |
Radar-Indicated Rotation |
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Regional View |
Local Area |
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The above plots are of rotation through the day on November 17th, 2013 as seen on NWS Doppler Radar. Note the long-lived rotation path from the supercell that moved from near Pekin and Washington east northeast to the far south Chicagoland area. Also take note of the other rotation paths seen, characterizing the common supercell mode of thunderstorms during the event. |
NWS Chicago Radar: 0.5° Reflectivity and Storm Relative Motion |
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From LaSalle Into Livingston County @ 11:38 am |
NWS Chicago Radar: 0.5° Reflectivity and Storm Relative Motion |
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From Grundy County @ 12:20 pm |
NWS Chicago Radar: 0.5° Reflectivity and Storm Relative Motion |
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From Will County @ 12:45 pm |
NWS Chicago Radar: 0.5° Reflectivity and Storm Relative Motion |
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From Jasper County @ 1:55 pm |
Surface Weather Map on Nov 17, 2013 from 4 am-5 pm |
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The above image is of analyzed dew points. Dew points reflect the amount of surface moisture and values in the mid 60s as seen above are more typical of summertime. High dew points, coupled with warm temperatures, created instability far higher than normal for November, and really to extreme levels for this far north. The moisture also aided in keeping cloud bases lower, an ingredient often seen in significant tornado events. |
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?
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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:
Storm Prediction Center Outlooks |
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Issued Thursday (Nov 14th) for Sunday |
Issued Friday (Nov 15th) for Sunday |
Issued Saturday (Nov 16th) for Sunday |
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Storm Prediction Center Outlook Issued the Morning of November 17th |
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Particularly Dangerous Situation Tornado Watch Issued 8:40 am on November 17th |
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NWS Tornado Warnings Issued on November 17, 2013 |
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National |
Zoomed-In |
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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
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