THEWEATHERMOGIL:: Big chill enroute
The culprit is an upper level low located over the northern Mississippi River Valley this afternoon (Fig. 2). That low should move into the Ohio River Valley by Sunday, allowing colder air from Canada to infiltrate the eastern half of the U.S. (Fig. 3). Linked to this, a large surface high-pressure system will move into the Southern Plains, allowing a northerly wind flow across a large part of the eastern U.S. (Fig. 4).
Temperatures that were running some 10 to 15 degrees above average for the past week to ten days (and about seven to 10 degrees above average for the month of March) will drop to some seven to 10 degrees below seasonal values by Sunday and Monday. For example, the seasonal average for Birmingham, AL is 56 degrees. Tomorrow (Mar. 20, 2016), the average for the day is only expected to be 46 degrees.
© 2016 H. Michael Mogil
Originally posted 3/19/16