April 17-23. 2005
Midwest Weekly Highlights - April 17-23, 2005
An April Personality Change
This week started with a continuation of the warm weather that
characterized the first half of the month. By
week's end, however, the stage was being set for a change to a much
colder weather pattern for the Midwest..
Temperatures this week were above normal across the entire region
ranging from 6F above normal or more from western Missouri into central
Iowa, to1F to 2F above normal in northeastern Ohio (Figure 1). The
week
started out very warm, but gradually cooled as clouds and precipitation
associated with a strong upper level low suppressed temperatures spread
across the area. It was a feast or famine situation with
precipitation this week, with most precipitation occurring in two bands
across the region (Figure 2). The first extended
from western
Iowa across central Wisconsin and into northern lower
Michigan. The second extended from western Iowa/northwestern
Missouri through central Illinois, central Indiana, and much of
Ohio. Outside of these areas precipitation was generally less
then 75 percent of normal for the week. For the
month of April so far, the driest portion of the region continues to be
an area from extreme northern Indiana and Ohio through all of Michigan
and into central Wisconsin (Figure 3).
Central lower Michigan
has received 10 percent or less of their normal April precipitation to
date. As of the April 19 U.S. Drought Monitor (Figure 4)
Michigan, northeastern Wisconsin, and northern Indiana and Ohio were
categorized as being in Abnormally Dry conditions. Wildfires
were
still a problem in northern lower Michigan early in the week because of
the dry weather.
Warm
Start
Clouds of dust and the throb of diesel engines marked the warm, dry
weather early in the week as agricultural producers proceeded full tilt
with corn planting in the Midwest. Temperatures were in the
70s and low 80s early in the week Marquette (in the Upper
Peninsula) reached 79F on April 18, which broke the old record of 76F
set in 1994. A number of high temperature records were set in
Michigan on April 19. Lansing, MI tied its record for the date (81F),
first reached in 1958 and again in 1985. Records were also
broken in Alpena (83F, old record 76 in 2004); Sault Ste Marie (81F,
old record 76F in 1987); Traverse City (84F, old record 80F in 1987);
Flint (83F, old record 81F in 1958); and Detroit (83F, tied record set
in 1977).
Storm
Winds Up Over Plains - First of Two Punches
While the central and eastern Midwest enjoyed warm and dry weather, a
storm system was gathering strength over the Central Plains on April 20
(Figure 5,
Unisys). A nearly stationary boundary was parked
over Iowa, providing the focus for showers and thunderstorms.
By the afternoon of April 20 heavy thunderstorms were ongoing over Iowa
south through Missouri. Mason City, IA set a new daily
rainfall record of 2.74 inches, more than doubling the old record of
1.27 inches set in 1993. In addition to heavy rain, the
storms produced large amounts of hail in central Missouri. In Pulaski County,
heavy rain and hail ranging in size from 1/4 inch to
more than 1 inch brought traffic on I-44 to a stop for a two-mile
stretch. In Dixon, MO (Pulaski County) hail continued to fall
for 30 minutes reaching almost an inch in size. There were a
number of reports of cars damaged due to the hail.
Later in the day and during the evening hours heavy thunderstorms
developed over central and east-central Illinois and west-central
Indiana, leaving some locations with more than 3 inches of rain.
Punch
Two
By the morning of April 21 the cold front had worked its way to the
Ohio River, leaving only scattered showers over the central
Midwest. However, another low pressure system was developing
in response to a developing upper level trough swinging south out of
Canada and into the northern plains. Over the next 24 hours
the upper level system intensified, and by the morning of April 22 a
distinctive cloud swirl marked the low pressure system in
western Missouri (Figure 6). Most of the rain
was falling
northwest of the low center in Iowa across to southern Wisconsin and
southern Michigan.
The low moved slowly across Illinois on April 22. Some severe
thunderstorms
developed over southern Illinois, Indiana, and Kentucky as the strong
cold front collided with the warm air ahead of it on April 22 . An F0
tornado was reported just east of downtown Louisville, KY early in the
evening of April 22. The storm produced intermittent minor
damage, destroying the roof of a business and flipping an empty
semi-trailer. Witnesses also reported pea-size hail covering
the ground to a depth of one inch.
The low deepened
considerably as it moved to a position over eastern Ohio by the
morning of April 23 (Figure 7).
As the low pressure system continued to intensify it funneled cold air
out of Canada and across the Great Lakes. High
temperatures on April 23 were only in the 30s in Michigan, and reached
only the mid 40s over the rest of the region, except for Missouri and
western Iowa, where sunshine helped temperature reach the low
50s. The chilly April temperatures were accompanied by winds
gusting to 40 mph or more, producing wind chills in the teens and
20s. Snow flurries were reported as far south as central
Illinois and Indiana, while in Michigan and Ohio steadier snow was
beginning and the stage was being set for a record-breaking April snow
storm. The snow event will be covered in the April 30 edition
of the MWCW.