Warm Week in Minnesota
Warm temperatures remained in the Midwest into the second week of November, as above-normal temperatures were common across a large portion of the region (Figure 2). Average temperatures were mainly in the 40s for the week
(Figure 1). While average temperatures in the 40s were near normal in the Ohio River Valley, they were well above normal in Minnesota. Most of the state had temperatures 9-13°F above normal during the period. Maximum temperatures were even more above normal, at 10-14°F across most of the state
(Figure 3). The only significant area of below-normal temperatures was minimum temperatures in Missouri through Indiana (Figure 4). With yet another warm week, the first half of November 2015
(Figure 5) has been much the opposite of the first half of November 2014 (Figure 6).
Storm System Brings Wet Weather
While some precipitation fell across the eastern reaches of the region to start the week, most of the Midwest’s precipitation came from one large storm that passed through the region on November 11-13 (Figure 7). Heavy rain ranging from 1.50-2.00 inches fell from northwest Iowa through the U.P. of Michigan as the storm tracked to the northeast on November 11 (Figure 8). This led to departures of over an inch above normal in those areas (Figure 9). In some cases, this was more than five times the normal amount of precipitation for this time of year (Figure 10). Some of that precipitation fell as snow in the Arrowhead of Minnesota and the U.P. of Michigan (Figure 11). Over five inches of snow fell in some areas in the 24-hour period through the morning of November 13 (Figure 12).
Elsewhere in the region, smaller amounts of rain fell along the system’s cold front. In most cases, this wasn’t enough to reach normal, as Missouri and southern Illinois received less than half the normal amount of precipitation. A storm earlier in the week in eastern Ohio was enough to bring that area slightly above normal precipitation for the period.
Strong November Storm Causes Severe Weather, High Winds
All of the ingredients were in place on November 11 for a somewhat uncommon November severe weather outbreak across Iowa, northern Missouri and northwestern Illinois
(Figure 13). Warmer than normal temperatures helped in creating enough instability for stronger storms to form, as a potent storm system moved through western Iowa. Multiple tornadoes formed, including an EF-1 tornado west of Avoca, IA and an EF-0 that went through the Des Moines Airport. Later that night, the Des Moines Airport also reported snow, a relatively rare event. Wind damage occurred along a line of storms that moved through Iowa and northwest Illinois. A wind gust of 71 mph was recorded at the Peoria airport while many other wind gusts of 50 mph or more were reported. As the storm moved out of the region on November 12, high winds continued to be reported as a strong area of high pressure filled in behind the storm. Wind gusts of 40-55 mph were common across Illinois and southern Wisconsin, with a few wind gusts in the Chicago Metro area in the 60-71 mph range. As the storm moved east, these winds caused a seiche on Lake Erie, with a large rise in water levels in Buffalo and fall in Toledo (Figure 14). Winds finally subsided by the afternoon on November 13.
Drought Holding Steady
The latest update from the National Drought Mitigation Center showed little change in drought area across the Midwest through November 10 (Figure 15). Over 12.5 percent of the region remained in moderate drought with over 38.5 percent of the region considered at least abnormally dry. Unfortunately, the storms on November 11 mostly dropped heavy precipitation on areas that were not in drought. Some improvement could occur in the U.P. of Michigan, however, where over an inch of precipitation fell in areas currently in moderate drought. Also, well above normal precipitation was expected through the next week, which could lessen drought concerns considerably (Figure 16).