Thunderstorms to unleash downpours amid record-breaking warmth; threat of flooding and severe weather to grow Tuesday



Thundery rains will come in waves Tuesday and well into Tuesday night, few likely to be wetter than those predicted to hit in the greatest numbers later Tuesday and Tuesday night.



When combined the 0.63″ which fell at O’Hare Sunday, the additional 1.83″ of rain predicted on average to fall in the next 36 hours is to make this the wettest weather system since 2.89″ fell here 9 months ago on May 3-7.



Chicago’s Tuesday warmth has Arkansas/Louisiana/Gulf of Mexico origins



But it’s not just the rain which is making weather headlines Tuesday. Abnormally mild temperatures are in the news across the Midwest as well.



Tuesday’s warmth here in Chicago has ridden powerful southerly winds northward since Monday. The warm temperatures in the area Tuesday had origins over Arkansas, Louisiana and the Gulf of Mexico just 24 hours ago.



The 65-degree high projected for Chicago Tuesday easily replaces the day’s previous 99-year record high of 59-degrees set in 1914 and is a reading just 2-degrees shy of the city’s all-time January record high temp of 67-degrees set back on Jan 25,  1950. Only 5 of the 34 January 60s on the books have made it to 65-degrees.



Temps in the 60s in January are incredibly rare—a fact which can’t be overstated! In fact, just 21 of 143 Januarys since records here began in 1871 have produced 60s.



The city’s last 60+degree January temperature took place 5 years ago when the mercury hit 65-degree on Jan 7, 2008.



Model forecasts produce eye-popping rain totals topping 2″; storm may become area’s heaviest in the 9 months since last May



The area is short of moisture and needs the rain. But the average of 1.83″ predicted for Chicago—and the many 2″ and higher amounts expected on the city’s periphery—could amount to “too much of a good thing”.



The trouble is, sub-soils are frozen and the rains aren’t able to soak into the ground. This is likely to lead to standing water as pools of water collect above the frozen layer. The fear then becomes falling temperatures predicted Wednesday will lead to a dangerous freeze-up of untreated wet pavements and any pools of standing water which remain as the arctic air hits. The result could be quite dangerous.



First round of storms unleashes 1.13″ on Chicago Heights overnight



The area’s first strong cluster of t-storms with this system hit last evening as incoming warm air destabilized the atmosphere.



An eruption of still more storms is likely to occur, and never more prolifically than later Tuesday and Tuesday night.