Midwest Overview - March 8-14, 2003

The Midwest weather was on a roller coaster during the week, but when all was said and done temperatures ranged from near normal in southeast Kentucky to 15F below normal in northern Minnesota (Figure 1).  Precipitation was generally confined to a band from western Missouri to central Illinois to north-central Ohio (Figure 2).

On March 8 temperatures across central and southern Missouri, Illinois, and Indiana soared into the 50s and 60s on strong southerly winds. To the north, a strong cold front marking the leading edge of an arctic air mass was sweeping through the Midwest and temperatures in northern Illinois, Iowa, Wisconsin, Minnesota and Michigan were in the teens and 20s.  The clash of the two air masses resulted in thunderstorms across southern Illinois and Indiana, where the first severe thunderstorm watches of the year were issued that afternoon. However, only there were only a few reports of severe weather. By the morning of March 9 the cold front had reached the Gulf coast (Figure 3), Temperatures across the Midwest ranged from -10F to -15F in Minnesota to the upper 20s near the Ohio River. On March 9 numerous record low maximums were set, followed by record low minimum temperatures on March 10.

As high pressure drifted east on March 11 southerly winds on the back side of the high brought warmer air back into the Midwest, while yet another surge of cold air started to drop south through the Great Lakes.  By the morning of March 12 the front had stalled from the Missouri-Iowa border through northern Illinois and southern Michigan.  Late on March 12 a mesoscale convective system (MCS) developed over central Missouri along the front and moved eastward into Illinois during the night.

Severe thunderstorm watches were issued for parts of Missouri and Illinois, and the some of the thunderstorms did produce severe weather, mostly large hail (Figure 4).  The thunderstorms dropped one to two inches of rain in a band that generally paralleled Interstate 70 in Missouri and Illinois (Figure 5). The cold front maintained the thunderstorms as it moved through Indiana, Ohio, and Kentucky on the morning of March 13.