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 The preliminary statewide average precipitation for April was
4.58 inches, which is 0.80 inches above the long-term average.
An active spring weather pattern resulted in a majority of
regions in northern, eastern, and southern Illinois receiving
more than 100 percent of average monthly precipitation, with
localized amounts approaching 200 percent. Smaller regions of
the state in west-central Illinois, roughly between the
Mississippi and Illinois rivers, are the only locations to
receive near or below average precipitation for the month.
The heaviest precipitation fell in extreme southern Illinois,
especially in counties bordering the Wabash and Mississippi
rivers, where 6 to more than 8 inches was common. The highest
total in the state was reported at a station near Cobden in
Union County with 8.31 inches.
Heading into May, flooding remains an ongoing concern for the
state, as soil moisture remains in the 90th to 95th percent
range.
As of April 30, 134 river gages affecting Illinois were reported
with crests in minor, moderate, or major flood stages. The
greatest threat continues to remain along the Mississippi River.
River flooding concerns were intensified by several days of
heavy rain during the last week of April.
April snowfall occurred primarily during two short-lived, yet
notable, late-season events that impacted many in the northern
portions of the state.
The first event on the weekend of April 13 and 14 brought
widespread reports of 1 to 5 inches along a corridor extending
from near Quincy, and running northeast toward Chicago and the
Illinois/ Wisconsin border. Several localities west and north of
Chicago reported from 6 to more than 8 inches of snow. Notable
accumulations were measured as far south as Peoria.
An accumulation of 5.4 inches at the Chicago O’Hare Airport tied
the record for the snowiest calendar day this late in the
season. April 16, 1961, also recorded 5.4 inches of snow.
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On April 27, a second snow event brought a variety of
wintry precipitation types to locations in northern Illinois,
including another round of accumulating snow for many from Chicago
and points north and west. With 3.7 inches, this was the latest snow
event with 2 or more inches on record for Rockford in Winnebago
County.
The maximum monthly snowfall in Illinois was reported
at a station near St. Charles in Kane County with an impressive 13.5
inches.
Despite several significant temperature swings throughout the month,
which are common during springtime, statewide April temperatures
finished right around the long-term average. The preliminary average
statewide April temperature was 52.0 degrees, which is 0.6 degrees
below the long-term average.
A few pockets in extreme southern Illinois reported slightly above
average temperatures, and sporadic regions in northern Illinois
reported temperatures of slightly below the long-term average. This
is a welcome change from last year, April 2018, which ranked as the
second coldest April on record.
The highest temperature in the state was recorded at a station near
Jerseyville in Jersey County with a reading of 85 degrees on April
23. In contrast, the lowest temperature of 18 degrees was recorded
at a station in Altona in Knox County on April 1.
Looking ahead to the rest of May 2019, the Climate Prediction Center
is favoring probabilities of above average temperatures for the
southeast half of the state, with equal chances of above, near, or
below average temperatures for the northwest half of the state.
Unfortunately, an active weather pattern looks to persist, as the
May outlook favors probabilities of above average precipitation
statewide.
[Lisa A. Sheppard] |
