March 16--West to southwesterly winds tapping the huge 80-degree source air mass in the central Plains should push Chicago-area temperatures into rare 70-degree territory Monday afternoon.
Checking weather records dating to 1871, 70-degree or higher temperatures have occurred only five times on March 16.
The last time was just three years ago, when in the middle of the nine-day record string we experienced the hottest high for that date: 82 degrees.
Winds shift to the north as a cold front settles south through the area Monday night -- with cold Canadian high pressure flowing over the Midwest and Great Lakes.
Because the northwest-southeast-oriented polar jet stream will be over the area, the remainder of the week will put the area along the leading edge of a persistent cold high-pressure system.
With predominantly easterly winds providing additional cooling from the icy waters of Lake Michigan, Chicago will probably record near-normal readings.
Longer-range indications are that the upper jet stream flow will become even more northwesterly, keeping Chicago temperatures near or below seasonal norms the remainder of the month.
