Above is view of State Street, downtown Chicago, this morning, and below is surface plot for Midwest a bit before 07:00 am MST. The surface low is centered a bit north of Columbia, Missouri, with a central pressure of only about 1016 mb. However, surface pressures are very high to the north and east of the low, providing strong gradients. The low is expected to deepen and impact the entire northeast of the country tonight and tomorrow - from DC to Maine. This storm has already been the main weather news over the weekend.
Air travel has been delayed, mostly in Chicago area (Misery Map above for 06:00 am), and current delays/cancellations shown below. Situation will be very much worse by tomorrow morning.