90th Anniversary of the Tri-State Tornado: Illinois’ Worst Tornado Disaster

I am a little late in posting this, but March 18, 2015, marked the 90th anniversary of the Tri-State Tornado that struck Missouri, Illinois, and Indiana, on March 18, 1925 (map below).

This was the deadliest tornado in U.S. history with 695 lives lost and occurred long before there were systematic forecasts and warnings of tornadoes. While it predated the common F-scale used to measure tornadoes, it was considered by experts to be an F-5 event.  A few years ago there was a push to decide if this was one continuous track or not by examining all the evidence and interviewing survivors. It was hard to decide since there was no weather radar to track the storm. Some of the areas were very sparsely populated, leaving little documentation on the possible track.

Figure from Wilson, John W., and Stanley A. Changnon, Jr. (1971). Illinois Tornadoes. Circular 103. Illinois State Water Survey: Urbana-Champaign, IL.

Continue reading “90th Anniversary of the Tri-State Tornado: Illinois’ Worst Tornado Disaster”

Four Odd Tornado Seasons in a Row for Illinois

Click to enlarge. Source NOAA Storm Prediction Center.

So far the 2015 tornado season in Illinois and the rest of tornado alley is incredibly quiet. There are no tornadoes to report this year, except in the far Southeast and one in California. However, this quiet start is no reason to relax if the past few years are a guide.

Historically, the heart of the Illinois tornado season is March to June with two-thirds of our tornadoes occurring during those months. However, in the last few years, we have had more tornadoes occur outside of this period than inside.

And a lot of these tornadoes have been concentrated in just a few days of the year. In fact, 69 percent of the tornadoes in 2012-14 occurred on just 5 days. These high concentrations can put extra strain on forecasting, warning, and recovery operations.

Here is how 2012, 2013, and 2014 looked, compared to the historical averages. Continue reading “Four Odd Tornado Seasons in a Row for Illinois”

Wet Week in Southern Illinois, Warm Across Illinois

In the last 7 days, Illinois has received 1 to 3 inches south of Interstate 70 (map below). Most of that came from storms last weekend. However, the precipitation amounts dropped off rapidly northward in Illinois. Areas in the northern third of the state received little to no precipitation. We are keeping a close eye on the continuing dry conditions in northern Illinois. That area has been persistently dry for several months despite this winter’s snowfall.


Continue reading “Wet Week in Southern Illinois, Warm Across Illinois”

Spring Flood Risk – Minor For Most of Illinois

NOAA released their Spring Flood Risk today. According to their map, most of Illinois has a minor risk of flooding this spring. An area at risk of moderate flooding is seen in southern Illinois. Sorry for the non-transparent overlay on the map – their map, not mine.

sfoThe good news of sorts is that much of the upper Midwest, including northern Illinois has been dry for the last 3-4 months. In the last few weeks, what snow cover we had in the central US is gone, as this map shows.
Continue reading “Spring Flood Risk – Minor For Most of Illinois”

New NWS Outlooks for April and Beyond

The NOAA Climate Prediction Center released their latest outlooks for April and beyond today. Areas without shading are labeled EC for equal chances of above, below, and near-average conditions.


Here are the outlooks for April for temperature (left) and precipitation (right). Nothing much to report temperatures but the northern third of Illinois has an increased chance of below-average precipitation. This area has been dry all winter. Click to enlarge.

off14_tempoff14_prcp Continue reading “New NWS Outlooks for April and Beyond”

Tracking Illinois Soil Temperatures

As the snow turns to mud this week, this is a good time to advertise links for the soil temperatures in Illinois. The Water Survey operates a 19-station network of sites around the state collecting hourly soil temperatures at 4 and 8 inches under grass as well as an estimate under bare ground.

All this information can be found at the Illinois Climate Network Soil Data site. Below is just a screenshot of that page to show where you would find that information on the real web page.


Here is a snapshot of 4-inch soil temperatures as of 10 am, March 13, 2015. Soil temperatures are still near the freezing mark in the northern half of the state, but warm into the 40s and low 50s in the southern half of the state.


Historical Tornadoes in Illinois and the US

While tornadoes can happen any time of the year, the tornado season really starts to ramp up in March in Illinois (see plot below) and remains active through the spring and on into summer. April, May, and June are the three standout months historically. So far 2015 has been very quiet with no severe weather reported in Illinois so far, according to NOAA.


You can see more plots like this on our tornado plots page.

Historical Tornado Tracks

Continue reading “Historical Tornadoes in Illinois and the US”

How February and This Winter Stacked Up in Illinois

Here are the time series plots of the statewide average temperature for February and winter (December-January-February) from 1895 to present (source: NOAA NCDC).


In the first plot, I have a red box around the temperature for 2014 and 2015. The only other time that we had a pair of extremely cold Februarys was 1978 and 1979. All the other cold Februarys were one-off events. According to NCDC, the statewide average temperature for February 2015 in Illinois was 19.5 degrees and the 9th coldest on record. Last February was nearly identical at 19.4 degrees.


Continue reading “How February and This Winter Stacked Up in Illinois”

Last Below Zero Weather of the Season? I Hope.

Here are the lows this morning, courtesy of the National Weather Service office in Lincoln. Areas in blue were below zero. Champaign-Urbana reached -9 degrees, breaking the old record of 4 degrees set in 1899.


Of course, widespread snow cover (map below), clear skies, and calm winds were contributing factors in the hopefully last round of below-zero weather this season. nsm_depth_2015030605_Midwest



    DANVILLE AIRPORT                      -10
    ELIZABETH                             -10
    FREEPORT                              -10
    MCHENRY                               -10
    ROCHELLE AIRPORT                      -10
    DECATUR AIRPORT                        -9
    SIDELL 5NW                             -9
    STERLING AIRPORT                       -9
    PAW PAW 2NW                            -7
    WATSEKA                                -7
    MATTOON AIRPORT                        -6
    OGDEN                                  -6
    PANA SEWAGE PLANT                      -6
    PAXTON 2WSW                            -6
    ALTONA                                 -5
    AURORA AIRPORT                         -5
    DIXON                                  -5
    DWIGHT                                 -5
    LINCOLN NWS                            -5
    NEOGA 4NW                              -5
    ROBINSON WTYE                          -5
    ROCHELLE                               -5
    ROCKFORD AIRPORT                       -5
    ROSICLARE                              -5
    WAUKEGAN AIRPORT                       -5
    BARRINGTON 3SW                         -4
    EFFINGHAM 3SW                          -4
    KEWANEE                                -4
    PARIS SEWAGE PLANT                     -4
    RAMSEY                                 -4
    SULLIVAN 3S                            -4
    MONMOUTH                               -3
    MUNDELEIN 4WSW                         -3
    TUSCOLA                                -3
    BROOKPORT DAM                          -2
    CARBONDALE AIRPORT                     -2
    CHICAGO DUPAGE AIRPORT                 -2
    COAL CITY 4NNW                         -2
    KANKAKEE                               -2
    LACON AIRPORT                          -2
    PRAIRIE CITY 2S                        -2
    GRAND CHAIN DAM                        -1
    MINONK                                 -1
    MORRIS                                 -1
    MT VERNON                              -1
    OLNEY 2S                               -1
    BLOOMINGTON 5W                          0
    CHICAGO OHARE AIRPORT                   0
    GALESBURG                               0
    MOLINE AIRPORT                          0
    OTTAWA 5SW                              0
    SMITHLAND LOCK AND DAM                  0
    WINDSOR SEWAGE PLANT                    0
    ELGIN                                   1
    JOLIET LOCK AND DAM                     1
    MACOMB AIRPORT                          1
    PERRY                                   1
    SPRINGFIELD NE                          1
    AURORA                                  2
    CASEY                                   2
    CHICAGO BOTANIC GARDENS                 2
    GLADSTONE LOCK AND DAM 18               2
    JACKSONVILLE                            2
    NEW BOSTON LOCK AND DAM 17              2
    NORMAL 4NE                              2
    PARK FOREST                             2
    WINCHESTER                              2
    GRIGGSVILLE                             3
    RUSHVILLE 4NE                           3
    WHEATON                                 3
    CHICAGO WHEELING AIRPORT                4
    JERSEYVILLE 2SW                         4
    PITTSFIELD                              5
    BENTLEY                                 6
    CHICAGO MIDWAY AIRPORT                  6
    NASHVILLE                               7
    QUINCY AIRPORT                          7
    QUINCY LOCK AND DAM 21                  8
    KASKASKIA LOCKS                        10
    CAHOKIA AIRPORT                        14