Official Forecast through Wednesday. Forecast Discussion.

Official Forecast from the Forecast Center

Today: High 53. Temperatures will continue climbing slowly, with increasing winds and cloud cover throughout the day.  Mostly cloudy to overcast.  A chance of scattered light rain showers during the afternoon.  Low pressure system moves east-northeast near Northern Illinois by early evening.  Winds from the south at 20-25 mph in the afternoon. Stronger gusts possible.
Tonight: Low 47. Temperatures dropping very slowly as warm air advection increases in the mid levels.  Winds will begin to subside overnight, with winds from the southwest at 10-15 mph.  Chance of scattered showers as the low pressure system moves northeast into Canada.
Sunday, November 19: High 52. Cold front begins to move through tomorrow. Temperatures dropping through the afternoon. Winds from the west-southwest at 15-20 mph. Chance of rain and showers throughout the morning and early afternoon.  Overcast.
Sunday Night: Low 38. Cold front has moved through completely.  Showers move out of the area.  Skies still remaining mostly cloudy to overcast. System redevelops in the south towards the overnight hours. 
Monday: High 48. Skies remaining overcast as storm system redevelops in the southern Mississippi Valley.  Most if not all of the rain will remain south of the area, unless the storm system redevelops farther north.
Monday Night: Low 37. Skies mostly cloudy to overcast, as storm system begins to move northward.  Rain chances increase through the overnight hours.  Steady rain develops north of the warm front.  Winds increase from the east and northeast as pressure gradient tightens.
Tuesday: High 46. Skies overcast, as storm system moves northeastward.  Steady rain ahead of the warm front moves across the area, with some pockets of heavier rain.  Winds increase even more from the east.

Tuesday Night: Low 31. Skies overcast before midnight, becoming mostly cloudy to partly cloudy by the early morning hours.  Chance of rain or snow in the early evening.  Winds diminishing from the northwest.
Wednesday: High 44. Partly cloudy to mostly sunny.  Cold temperatures remain after frontal passage.  The next storm system develops over the Rockies, to affect the area by Friday and Saturday.

Forecast Discussion

During this time, I believe it will be almost always cloudy through at least Monday.  According to the latest GFS prog., the storm system that was originally thought to head through the Tennessee Valley, will move more northward than was originally forecast.  This is because the southeast ridge will be redeveloping after today's storm system moves through, in association with a positive AO and positive NAO regime.  Today through Sunday, showers will be scattered and light in nature, along with gusty winds today, and diminishing weaker winds tomorrow.  The current storm system will move through the area later tonight, bringing with it scattered light showers around here, and a heavy snowstorm in Wisconsin and Minnesota.  The storm system and its associated pressure gradient, will also move out of the area tonight, causing the diminishing winds.  Not much clearing is expected Sunday, as showers are still anticipated in the morning hours, with only mostly cloudy skies in the afternoon.  By Monday, the storm system will redevelop in the southern Mississippi valley, and lift northward.  It's associated warm front will cause clouds to increase once again, but the rain should remain south of the area.  Monday night, if the storm system does make a more northeastward turn, then expect rain to develop overnight Monday.  If it does not, expect a few showers on Tuesday, and blustery winds, along with dropping temperatures.  Tuesday, if the storm system makes the turn to the north, I would expect steady rain with a few embedded thunderstorms north of the warm front.  Heavy rain is even possible, with an inch or so possible according to the latest GFS forecast.  After Tuesday Night, expect clearing skies, and much colder air to infiltrate the region.  I would even expect temperatures to be colder than what I'm forecasting right now, as these temperatures are based off the GFS model output, which has had a warm bias.  Wednesday into Thanksgiving Day, expect temperatures in the lower 40's, and nighttime lows in the upper 20's and lower 30's, under clear skies both days.  By Friday, temperatures will be rebounding again, in advance of a potentially much stronger storm system, which would bring heavy rain to the area next Saturday and Sunday.  Stay tuned for further updates.