As low pressure intensifies in the Plains, an extended period of
southerly flow from the Gulf of Mexico up the Mississippi Valley into
the Midwest should see temperatures rising well into the 60s, and
occasionally the low 70s over northeast Illinois early this week. Sunday
to Tuesday, high readings may average nearly 20 degrees above normal.
Highs will probably peak Tuesday. Vertically stacked strong southerly
winds from the surface up to the jet-stream level just ahead of an
approaching cold front are responsible for Chicago's warm-up Tuesday. On
the same day, severe storms are expected to develop across parts of
Arkansas, Louisiana, Tennessee and Mississippi as the cold front
combines with low-level southerly winds and diverging jet-stream winds
aloft.
More rain and cooler
Computer models indicate a complex low-pressure system will surge out of
the southern Plains into the Midwest on Friday preceded and accompanied
by another wave of showers and thunderstorms. Northerly winds behind the
low center could usher in a sharp shift to colder weather and maybe snow
showers next weekend.
