May 11-24, 2007
Midwest Weekly Highlights - May 11 - 24, 2007
Warmer than normal temperatures were felt across Western sections of the Midwest. Temperatures peaked at over 6°F above normal in sections of Minnesota and Iowa while the East and Southeast areas saw below normal temperatures. Both the Upper Peninsula and lower sections of Michigan saw temperatures 3 to 5°F below normal for the previous two week period (Figure 1). Much of the rest of the region saw seasonal temperatures.
Prior to the 24th, precipitation across the much of the region was well below normal. From Missouri and east through the Ohio Valley, roughly 5-15% of normal rainfall had occurred. Northern Minnesota and Northern Michigan were the only areas to see at or above normal rainfall up until the arrival of the cold front on the 23rd and 24th (Figure 2).
EARLY STORMS / SEVERE WEATHER
Synoptically speaking, conditions have oscillated across the Midwest over the last few weeks. Surface low pressure, that had built over Alberta earlier in the period, had a trailing cold front on the 14th - 16th that sparked numerous storms. New precipitation records were set for two stations in Michigan on the 14th while on the 15th, many of the storms associated with its passage were severe. The Storm Prediction Center received six reports of tornadoes and hundres of reports of high winds. Some local effects of these storms included the loss of a spire atop the Basilica of the Sacred Heart at the University of Notre Dame in South Bend, IN, and power outages across parts of Chicago.
HIGH PRESSURE / DROUGHT
High pressure then settled in to dominate the weather pattern throughout the weekend and into the early part of the this week (Figure 3). The clear skies allowed for significant radiational cooling that resulted in record low temperatures in Illinois, Iowa, Kentucky and Michigan. These cool temperatures also prompted several frost advisories and freeze warnings across the region. Of special concern in the Cherry/Berry belt of western Michigan were the temperature-sensitive crops of blooming fruit trees/bushes/vines as temperatures dropped below freezing for several hours on May 18th(Figure 4 & Figure 5).
Dry weather occurred across much of the region during this time which resulted in some expansion of drought conditions. Farmers near Rice Lake, Wisconsin report that they have had little to no measurable rain since late April and that many small lakes and streams have dried up because of the dry conditions. They state that they are working in fields with no moisture. Nearby, sections of eastern Minnesota and western Wisconsin have seen barely 25% of the normal precipitation since late April. Also moving into D0 territory was the western third of Kentucky, while the eastern half of the state was moved into the D1 category (Figure 6).
COLD FRONT/ FLOODING
The next storm system to approach was responsible for severe weather across the plains early on the 22nd and then moved into the Midwest later in the week. The trailing cold front would brought a welcome change in temperatures across the region as record highs had been set in Indiana, Iowa, Kentucky, Ohio and Wisconsin (reference chart below). It also brought with it some of the needed rains to areas that have been moisture deprived. From May 11th through the 23rd, much of the Midwest was well below normal with total precipitation received (Figure 2). Looking at May 11th through 24th, the picture is drastically different across the Western Midwest. (Figure 7) While the rain would not be considered 'drought busting' for the hardest hit areas, it did help to add vital moisture to the ground, and keep many areas out of D0 or abnormally dry conditions with regards to drought.
Unfortunately for the areas of Missouri that are just recovering from some of the worst flooding that it has seen in over a decade, the latest system has brought another round of flood warnings. Tarkio Rivera at Fairfax, MO was one of the hardest hit areas from the previous flooding and the new flooding. They were one of the only locations to set a new high river crest record back on the 7th of May at 25.78' (Previously held at 25.60' in 1993). Flooding crested at 21.1' above flood stage at 8:54PM on the 24th, which would be categorized as Moderate Flooding. Many of the areas that saw flooding earlier in the month are under warning again with the latest cold front passages.
Agriculture
Farmers were able to take advantage of the dry weather conditions and really make an impact on their planting of crops. All states but Missouri are above the average planted crop for this time of year. Most states are also beyond the progress of 2006.
Corn Planting Progress (Percentage): Table, Image
Flood waters ravaged many sections of Missouri, and crops were slightly affected. Planted Corn Conditions elsewhere are primarily classified as fair or above.
Corn Crop Conditions (Percentage): Table, Image
Records
This table highlights the numerous records broken this week.
MCP/SSS