AA has posted a Midwest Storm Policy covering the period from 1/31 to Feb 2.

For those on mobile devices, here is the information:

Midwest Travel Policy
Due to the anticipated winter weather in the Midwest, American Airlines offer customers the convenience to change their plans. Customers ticketed to travel on AA flights to/from/through the airports listed below may change flights as shown below.

If you are traveling to/from/through:
Bloomington, IL (BMI)
Cape Girardeau, MO (CGI)
Cedar Rapids, IA (CID)
Champaign, IL (CMI)
Chicago O'Hare, IL (ORD)
Des Moines, IA (DSM)
Detroit, MI (DTW)
Dubuque, IA (DBQ)
Evansville, IN (EVV)
Flint, MI (FNT)
Ft. Leonard Wood, MO (TBN)
Ft. Wayne, IN (FWA)
Grand Rapids, MI (GRR)
Indianapolis, IN (IND)
Joplin, MO (JLN)
Kalamazoo, MI (AZO)
Kansas City, MO (MCI)
Kirksville, MO (IRK)
Manhattan, KS (MHK)
Marion, IL (MWA)
Milwaukee, WI (MKE)
Moline, IL (MLI)
Northwest Arkansas Regional, AR (XNA)
Oklahoma City, OK (OKC)
Peoria, IL (PIA)
Quincy, IL (UIN)
Springfield, IL (SPI)
Springfield, MO (SGF)
St. Louis, MO (STL)
Traverse City, MI (TVC)
Tulsa, OK (TUL)
Wichita, KS (ICT)

On the following dates:
January 31 - February 2, 2011

And your ticket was issued no later than:
January 30, 2011

You may begin travel as late as:
February 6, 2011

Original inventory required?
Yes