A very complex storm system will continue to develop over the center of the nation into Wednesday. Already a very mild and moist Gulf flow has developed as the initial surge of warm air pushed northward during Sunday. This warm surge will bring record breaking high temperature during Tuesday, along with the threat of severe weather and locally flooding rains. However, during Wednesday as the storm system intensifies and moves northeast into Canada, cold arctic air will return.
The Chicago metro area experienced a wide variety of weather during Sunday. A bit of snow and sleet turned into freezing rain as the air aloft warmed. By early Sunday night the precipitation became more convective with scattered thunderstorms over the area. Surface temperatures also warmed above freezing to allow the earlier glaze to melt. In the space of 24 hours temperatures went from 27 at Midway at 9:00 a.m. CST Sunday to 50 at 9:00 a.m. today, very impressive.
A weak front will drape over the Chicago metro area today and early tonight. The front will actually lower temperatures this afternoon north and near the lake. This will lead to fog and drizzle formation as the cold air bumps into the high dew points. Later tonight the front will push north of the area as another surge of moisture moves through. Showers and thunderstorms will move over the metro area later tonight. Some of the storms may produce small hail.
During Tuesday strong south winds will bump high temperatures into the low to mid 60s, record breaking. The record high for Chicago Tuesday is 59, for Rockford the record is 55. Precipitable water (evaporated column water) values are forecast to reach 1.4 inches, values that are normal in the summer, not late January. All this evaporated column water leads to possible very heavy rain Tuesday night as low pressure and a cold front move into the area. The graphic shows the expected GFS model precipitation through Wednesday morning.
The problem with heavy rain at this time is the frozen ground. The very mild temperatures through tomorrow night will not thaw the frozen ground which has the frost several inches deep. In essence the rain will be falling on porous concrete which will lead to local ponding of water and rapid runoff into rivers and stream. There is also the threat of severe weather with tornadoes in a long band from Texas to almost Chicago. Details can be found here.
You can follow my articles by clicking on the “Subscribe” link on top.
You can also follow me at http://www.facebook.com/allfish2 and at http://www.twitter.com/allfish2
Comprehensive weather articles and discussion can be found at http://www.storm-central.com