Third-Warmest February since 1873 will conclude with Severe Storms
The forecast calls for mid-60s to overspread the Chicagoland area today ahead of a strong surface front. This dramatic and warm conclusion to the month will likely make February 2017 the third warmest of all-time in the city:
Not content to go out quietly, the month will conclude with a bang. There is an enhanced risk of severe storms late tonight as a powerful low strengthens as it pulls northeastward through Iowa and into the Great Lakes area, dragging with it a surface reflection that will usher in very cold air tomorrow.
Here is the thunderstorm outlook from the Storm Prediction Center for tonight:
The main action should fire up around sunset, with the main threat of severe storms accompanying a powerful gust line between 10pm and 1am. This is a dangerous situation because it will be the middle of the night. In Chicago, the biggest threats are large hail, and very gusty winds. Here are some maps showing the likely passage of the storm front around midnight:
Gusty winds in excess of 45mph will likely accompany heavy rain, warm temperatures (60 degrees at midnight), high dewpoints, strong vertical shear, and CAPE values in excess of 1500 J /kg. The tornado chances to the south and west of the city are very high and an outbreak is possible / likely.
The radar at Chicago is out of commission, so monitoring these storms in the middle of the night without storm chaser eyewitness accounts will be especially challenging. Please pay attention to your local weather service office: https://www.weather.gov/lot/
And you can follow along with the storm prediction center here: http://www.spc.noaa.gov/exper/mesoanalysis/new/viewsector.php?sector=20#
Stay alert, and stay with me. Hello, March!
x Mick