November 2009 finished warmer and wetter than normal across most of central and southeast Illinois. Temperatures averaged 4 to 6 degrees above normal across the area. Springfield had its 6th warmest November on record, and Peoria its 7th warmest, with averages of 48.9 and 46.6 degrees respectively. Areas south of I-70 were drier than normal, but most of the remainder of central Illinois saw above normal rainfall.
After the unusually wet October, dry and warm weather helped to dry out conditions across central and southeast Illinois, during the first half of November. Temperatures reached into the mid 70's over much of the area on the 7th and 8th, reaching the upper 70s in a few areas west of the Illinois River on the 8th. Rainfall during this period was generally less than a half inch.
|Total rainfall from November 1-7, as analyzed by the Midwest Regional Climate Center.||Total rainfall from November 8-14, as analyzed by the Midwest Regional Climate Center.||High temperatures on November 8th.|
Despite the dry weather, the Illinois River continued to rise in response to the excessive October rain. The river peaked nearly 9 feet above flood stage at Havana and Beardstown around the 6-7th, and around 7 feet above flood stage at Meredosia.
An upper level low became cut off over the region during the middle of the month, lingering for a few days. Significant amounts of rain fell across the area, in excess of 3 inches generally along the I-72 corridor southwest toward St. Louis (see image at left, courtesy of the Midwest Regional Climate Center). This resulted in renewed river flooding, especially in the Illinois and Sangamon River basins. Crests on the Illinois River occurred around the 23rd, although rises were not as high as earlier in the month.
Temperatures remained above normal much of the 2nd half of the month, with a cool period around Thanksgiving. Later that weekend, highs had risen back into the 60s, but began a slow cooling trend the remainder of the month.