Another round of much needed rainfall on the way

12:45pm Update:  Scattered showers and thunderstorms have developed as the first round of warm/moist air moves north out of Missouri.  I expect this activity to reach the Rockford area within the next hour or two and continue to remain scattered throughout the afternoon.  As the cold front moves through there are greater indications that heavier rain and thunderstorms will develop near the Mississippi River and move east through midnight.

This image is the RAP, Rapid Refresh, model used for short term forecasting.  The time frame here is at 7pm this evening just as the cold front is moving east of the Mississippi River.  As I discussed in a previous post the front will be moving through the same time the upper level low is strengthening and a second slug of moisture lifts north.  Very strong winds within the jet stream will round the base of the upper level low and help enhance lift (cause air to rapidly rise) in the atmosphere.  This process will allow for intensification of a line of showers/thunderstorms around 7pm over northern Illinois and southern Wisconsin.  While severe weather isn't anticipated some of the storms that do move through will have a lot of energy and momentum to work with which could produce wind gusts at the surface over 50 mph.  Rainfall totals also appear to be quite impressive with totals near an inch or more across the area by Thursday morning.

Update:  Currently looking through some of the latest data regarding the storm system for this evening and some of the shorter term models are suggesting a significant band of convection developing near sunset and lasting into the overnight.  Details to come soon.  Stay tuned!

Another round of some much needed rainfall may be on the way this evening and overnight as a strong cold front moves through.  While moisture from the Gulf of Mexico won't be in full supply with this next system we may make up for that with the amount of lift, or rising air and energy, in the atmosphere. 

Clouds will continue to increase this morning with skies becoming mostly cloudy by noon.  Temperatures will rise near 70° ahead of the front before dropping back into the low 60s by dinner.  Rain will begin to overspread northern Illinois and southern Wisconsin around 3pm and continue into the overnight.  The front will move through between 6pm and 7pm at the same time the upper level low will strengthen.  These two things combined should be able to generate enough lift in the atmosphere for heavy rain and embedded thunderstorms to form and persist into the overnight.  Rainfall totals from tonight could top an inch or more for some before the low lifts northeast into New England this weekend.

Severe weather isn't anticipated but as showers and storms form the amount of energy in the atmosphere could cause some thunderstorms to produce gusty winds.