The nocturnal thunderstorms could get Chicago area residents up from their slumber tonight–and also bringing the potential for some much needed rain.
An amalgam of model projections suggests the storms are to ride into the city and close-in suburbs from the northwest after midnight, likely sweeping through in the northwest from 2 a.m. to 4 a.m. and making their way across the area with strong winds and downpours over at least a swath of the metro area.
While estimates of rainfall run the gamut from 0.05″ in least affected areas to 0.90 to 1″ in other areas. And there are suggestions a few heavier cells could produce totals northwest of the city over sections of north-central Illinois centered on Rockford in the 2-3″ range. But importantly, these convective rains–i.e. rains spawned by t-storms – distribute their rains notoriously unevenly.
Another issue with thunderstorms is the fact rains come quickly and with great intensity where the heaviest cells occur. So not only their rains highly selective–drenching one area and only swiping others–but the fast rate of fall means these rains can run off quickly rather than percolating into the soil.
These storms will reach up into powerful jet stream winds and resemble “northwest flow” t-storms which are southeastward-moving but able to mix some of that jet stream wind energy down to the surface in what can be damaging winds.
There is a threat of severe weather along with including drenching downpours.
For the latest weather updates, go to wgnv.com/weather.