The year's second warmest Chicago temperatures fueled powerful, downpour and wind-generating thunderstorms which lashed much of the metro area overnight.
High temperatures Monday hit 92-degrees at Midway and 89 at both O'Hare and Chicago's lakefront, where the reading was 18-degrees warmer than Sunday’s shoreline 72. The warmth and influx of Gulf moisture laid the atmospheric foundation for the storms which followed overnight.
The storms hit many areas with torrential rainfall and unleashed wind gusts clocked as high as 61 mph in Chicago's west Loop, 57 mph at the offshore Crib, 53 mph at Douglas Park in the city, 47 mph in Old Town and 56 mph at Park Forest.
Rainfall was torrential. Of the 1.16" measured at Carbon Hill in Grundy County, 1.10" fell in just 35 minutes. Lombard's 1.64" tally fell in just 75 minutes.
Chicago area storms generated by same spring system responsible for the devastating Oklahoma tornadoes; hundreds of severe weather reports including dozens of tornadoes have been tallied by Storm Prediction Center past 2 days
The storms which swept Chicago overnight were products of the same huge spring low pressure system behind the devastating Newcastle, Moore and southern Oklahoma City tornado, one of the worst and mostly deadly twisters to hit a state in which tornadoes are no strangers.
Though official National Weather Service storm surveys are to take place beginning Tuesday, the mammoth tornado, at times more than a mile and a half wide as it churned along a 20 mile path over its 40 minute meteorological reign of terror, was believed to be of AT LEAST “EF4” intensity---suggesting winds of 160 to 200 mph if not higher.
The twister touched down at 2:56 pm Monday afternoon and was on the ground until 3:36 pm according to preliminary reports. The death and devastation it produced covered at least 30 square miles, involved an estimated 4,000 homes and produced a “debris ball”----a radar return produced by airborne debris--- which ranked among the largest forecasters have seen.
Debris hoisted aloft by the gargantuan wind machine traveled 250 miles to Branson, Missouri!
Track of the Tuesday "Sooner State" tornado shockingly close to a huge May 3, 1999 twister there; Monday's was the third major tornado to hit the same swath of terrain in the past 14 years
The path followed across central Oklahoma by Monday's twister nearly paralleled a benchmark May 3, 1999 tornado, which killed 26, was on the ground 36 miles and generated damage put at $1.1-billion dollars.
Two other twisters---including Monday's--- have devastated the same region of the state since the 1999 F-5 twister. That storm produced Doppler-scanned winds of 318 mph---the strongest ever measured in a tornado.
Veteran severe weather researcher reports even the twister’s "sound" was different and particularly ominous
One of the country’s leading severe weather researchers and a 41 year veteran of storm chasing, had a first-hand view of the tornado's trek across Oklahoma Monday. Describing the vortex of the tornado as rain-wrapped, Dr. Chuck Doswell reports the sound the twister made was like no other tornado he's observed in his career.
While most tornadoes he’s observed over his more than four decades of tracking twisters produced a sound comparable to a "waterfall", Monday’s storm, he reports, generated a far more menacing sound, more like a fleet of jet fighters---an disturbing sound which may well have been a by-product of the cataclysmic devastation it was producing.
Rains aren't over in Chicago; several new rounds of downpours to hit Tuesday night into Thursday morning
Sunshine is likely to be out a number of hours Tuesday. But the threat of additional downpours isn’t over.
Conditions capable of spinning up active or severe storms remain in place, and several additional waves of drenching rains are a good bet Tuesday night and again Wednesday night into Thursday morning.