November 1-7, 2003
Midwest Weekly Highlights - November 1-7, 2003
Heavy Rains Help Drought Situation
The first week of November was dominated by a reversal of normal mid-tropospheric circulation, with a large trough to the west of the Midwest and a large ridge over the eastern Midwest and East Coast. A stationary boundary between the northwestern and southeastern portions of the Midwest provided a focal point for several days of rain centered in a band from southwestern Iowa to central Michigan. Precipitation totals reached 3-6 inches over this 100-mile-wide swath (Figure 1), and a much wider area received above normal percentages of precipitation (Figure 2). To the north of the main precipitation axis, considerable amounts of snow fell in Minnesota (Figure 3), with International Fall's total of 9.0 inches shattering the previous daily record of a mere 2.1 inches on the 4th. A tremendous influx of warm and moist air preceded the slow moving cold frontal boundary, yielding many high temperature records early in the period. Temperatures were up to 15°F below normal for the week in northwestern Minnesota while reaching more than 12°F above normal in eastern Ohio (Figure 4). The precipitation in Iowa, southern Wisconsin, and central Michigan was quite welcome in these drought-afflicted locations, and all of these regions experienced a one-category improvement in the U.S. Drought Monitor map for the 4th (Figure 5, National Drought Mitigation Center). The core of drought centered in southeastern Minnesota received some light rain, but not nearly enough to improve the extreme drought situation there.
In a season where the jet stream usually flows over the area from west to east or northwest to southeast, a very strong southwesterly flow developed over the Midwest due to a low pressure trough and high pressure ridge spanning the US (Figure 6, Climate Diagnostic Center). The boundary in between colder than normal air and warmer than normal air provided the lift necessary for substantial rain to develop on the 2nd (Figure 7a, NWS), 3rd (Figure 7b, NWS), and 4th (Figure 7c, NWS). Madison, WI, received heavy rain on all three days, setting a new daily precipitation record on each day: 1.41 in, 1.96 in, and 1.60 in. Combined with a 0.11 in total for the 1st, the first four days of the month yielded 5.08 inches of rain in Madison, which would make November 2003 the 5th wettest November on record even without more rain during the month. The Milwaukee National Weather Service Office prepared a high resolution graphic of precipitation from this event (Figure 8, NWS).
Considerable drought relief occurred in Iowa, also, as tremendous rain accumulations can be seen in the radar summaries for Des Moines (Figure 9, NWS), and Davenport (Figure 10, NWS). Other 1-day precipitation records were set on November 3 at Dubuque ( 2.17 in), Des Moines (3.55 in), and Waterloo (3.00 in) Iowa first order stations and about 8 Iowa cooperative observer sites. Michigan also had significant drought relief, with both Grand Rapids and Lansing setting new precipitation records on the 2nd, and Lansing and Flint typing and setting records, respectively, on the 3rd. Because of the dryness in the rainy locations in Iowa, Wisconsin, and Illinois, very little river flooding was evident despite the heavy rains. Most of the rain soaked into soils that had not yet frozen, recharging water levels for the next growing season. However, major street flooding occurred in metropolitan areas, including Chicago and Milwaukee, causing some auto accidents and damage to flooded cars and basements. Some power outages occurred in Michigan due to the thunderstorm activity on the 4th.
Not only did the November 1-7 period have heavy precipitation in the Midwest, but the temperature extremes where also noteworthy. Several high temperature records were tied on November 2, including at Joplin, MO, and Cleveland, OH. On November 4, high temperatures were in the upper 70s through most of the southern Midwest (Figure 11), and morning lows were only in the 50s (Figure 12). Joplin, MO, set a record for highest minimum temperature. Record high temperatures were recorded on the 4th in Jackson, KY; Cleveland, Cincinnati, Toledo, Findlay, Mansfield and Youngstown, OH; Indianapolis and Fort Wayne, IN; and Detroit, MI. At the end of the period, though, a reinforcing influx of cold air was entering the region in back of a clipper system passing through the Upper Midwest, plunging temperatures well below normal. Before midnight on the 7th, International Falls, MN, set a new daily low temperature of -9°F, and also set a new low for the following day. Marquette, MI, set a new one-day snow fall record on the 7th, receiving 2.3 inches of snow. A number of other locations in the UP of Michigan received even more snow, up to 6 inches