A winter storm watch has been issued for parts of Missouri and Illinois due to a late season winter storm which is expected to affect our area this weekend. Precipitation will begin as rain and then change over to snow when colder air arrives Saturday night. The snow should last through most of the day on Sunday. The highest accumulation are generally expected to be north of I-44 in Missouri and I-70 in Illinois. We will continue to refine the forecast with the latest observations and model guidance.   (Please visit http://weather.gov/lsx for more information.)