A very strong low pressure system will affect the Aurora area Wednesday and Thursday. The worst of it should be in the area from late Wednesday into Wednesday night. Heavy rainfall totals and potentially damaging winds will accompany this system.
The Storm Prediction Center shows a strong jet stream, with winds over 120 knots, is tearing south into the nation from Canada. This is digging out a potent upper level trough to the south. This trough will strengthen and close off into an ominous upper level low that will grow to cover most of the eastern United States.
At the surface, the upper level low will strengthen a low pressure that is currently over the Ohio Valley. It will also pick up a subtropical low that is affecting Florida. The two systems will phase into a strong surface storm that will track to the northwest and move across northern Indiana. It will then race off to the northeast later in the day on Thursday.
Strong winds will be a part of this system. The low pressure will drop below 990mb by early Thursday morning, with a 1026mb high to the north in Canada. This strong pressure gradient will produce powerful northeast winds that will blow down Lake Michigan and into the area. Winds will gradually increase throughout the day on Wednesday, with gusts approaching 45mph. Winds will peak Wednesday night into Thursday morning when the storm is closest. At this time, winds may be sustained 30 to 40mph with gusts between 50 and 60mph. The strongest winds will be closest to Lake Michigan, where the air is coming in from open water and not slowed down by land.
Heavy rains are likely with the system as it sucks in Gulf of Mexico and Atlantic moisture. The moisture will be pulled around the low onto the northwest side, which is where Aurora sits. Some lake effect rain showers could begin to affect the area tonight, but more organized rains will push in from the southeast by Wednesday morning. The heaviest rains will occur Wednesday night, before tapering off Thursday morning. Western areas could see close to an inch of rain, while locations close to Lake Michigan may see 3 inches of rain.
The National Weather Service in Chicago hoisted a lakeshore flood warning as the winds may produce waves up to 22 feet! This will flood portions of Lake Shore Drive. The strong winds have the potential to cause tree damage in some locations. Flooding isn’t too much of concern, because of recent dry weather. This storm will pull out of the area in time for the weekend.