February 15-21, 2004
Midwest Weekly Highlights - February 15-21, 2004
Winter’s grip broken in the Midwest.
After a cold start to the week,
much warmer air surged northward and spread across the Midwest,
finally breaking the spell of cold weather that had gripped the a
region for the past three weeks. The return of warm air was
reflected in the temperature departure pattern for the week (Figure 1). The coldest
area was a band across the northern central portion of the Midwest where
departures ranged from 4F to 6F below average, while the warmest air was
found over central and southern Missouri. Precipitation was generally
well below normal for the week except for areas of Minnesota and Wisconsin
which received snow in a late week storm (Figure 2).
Some of the coldest air of the season was experienced over the northern
Midwest on the morning of February 15 as high pressure settled in
over the Great Lakes. International Falls, MN established a new low temperature record
of -32F, breaking the old record of -29F set in 1973. However, the
cooperative weather observer in Tower, MN reported a low temperature of -41F.
The observer at Embarrass, MN reported a low of -44F, adding more ammunition
to the “battle of the cold spots” with International Falls claiming itself as the Icebox of the Nation, while Embarrass claims itself
as The Nation’s
Cold Spot. Either way, no one could argue it was extremely cold
in the northern Midwest that morning. Low temperatures were below zero
over most of Minnesota, Iowa, Wisconsin, and southern lower Michigan (Figure 3, Unisys). By
February 17 southwesterly flow had set up over the region and temperatures
started to climb. In Minneapolis-St. Paul the Twin Cities ended a string
of 31 consecutive days below freezing, the longest such streak since the
winter of 1985-1986. The 42F on February 18 was the highest temperature
reached since December 27th. In addition, Duluth reached 45F F on February
18, the warmest temperature there since 50 F on November 20th.
By February 19 colder air returned to the northern Midwest as a storm
developed in the Central Plains. Southerly winds ahead of the
system continued to pump warm air into the central and southern Midwest,
with high temperatures reaching the low and mid 70s as far north as
central Missouri and into the mid 50s in central Illinois and Indiana
(Figure 4,
Unisys). This
storm dropped several inches of snow on central Minnesota and northern
Wisconsin on February 19 and 20 (Figure 5),
with the Michigan Upper Peninsula and a few of locations in northern
Wisconsin reporting 10 to 12 inches by late afternoon on February
20. South of the snow
area, showers swept though the remainder of the Midwest, with most precipitation
amounts less than 0.25 inch. By the end of the week, the mild weather had
eroded snow cover in Missouri, Illinois, and Indiana, but 1 to 2 feet of
snow still blanketed the northern half of Minnesota, Wisconsin, and northern
lower Michigan Up to 3 feet of snow was on the ground across the Upper
Peninsula (Figure 6).