Midwest Weekly Highlights - March 18-24, 2013

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Storm System Brings Significant Rainfall and Late-Season Snowfall

Total precipitation was significantly above normal in the southern Midwest over the last week, with areas in eastern Missouri, southern Illinois, southern Indiana, and Kentucky receiving 200% to 300% of normal precipitation (Figure 1). Total precipitation for the week ranged from only 0.01" to 0.05" in southern Minnesota to 2.5" to 4" in Kentucky, southern Illinois, and eastern Missouri (Figure 2). There were several daily precipitation records set throughout the week, and a few monthly precipitation records

The high precipitation values in the southern Midwest resulted from a large storm system that moved through the central Midwest on March 24th (storm totals are reported on the 25th) (Figure 3). This system brought several inches of snowfall to Missouri, Iowa, Illinois, and Indiana, while bringing significant rainfall further south. Snowfall totals were greatest in Illinois, with a large area around Springfield, Illinois (Sangamon County) receiving 12" to 15" and the greatest totals of 15" to 18" reported just to the northwest of Springfield (Figure 4). There were over 275 daily snowfall records associated with this system on March 24th and 25th, and just over 40 monthly snowfall records. Snowfall amounts during this late-season winter storm ranged from 2.5" to 12.5" above normal for this time of year (Figure 5). As a result of the rainfall and severe storms that moved through very southern portions of the Midwest during this storm system, there were a few severe weather reports (Figure 6), including a small EF1 tornado reported in Somerset, Kentucky (Pulaski County).
 

Unseasonably Cold Temperatures Continue

Average temperatures were significantly below average across the Midwest region during the week (Figure 7). A majority of the region was at least 9°F below normal, with the largest departures of 21°F to 22°F below normal in northwestern Minnesota. Temperatures have also been very chilly across Iowa. Cresco, Iowa (Howard County) had a low temperature of -4°F on the 21st, which is the latest subzero temperature recorded in Iowa since March 26, 1996. As a result of the cold temperatures across the region, freezing temperatures (32°F and 28°F) are still common across the central United States (Figure 8). The unseasonably cold temperatures resulted in a few hundred daily temperature records, all of which were record lows.
 

Drought Update

Unfortunately, the precipitation during the week mainly fell in drought-free regions of the Midwest, resulting in little change on the US Drought Monitor across drought-stricken areas (Figure 9). A majority of Minnesota and Iowa are at least in moderate drought (D1), while some portions remain in extreme drought (D3). On the contrary, the latest US Drought Monitor indicates that Illinois is now drought free, which is the first time since April 3, 2012. According to the Illinois State Climatologist, most areas in Illinois have seen positive responses in soil moisture, stream flows, lake levels, and groundwater levels since the fall. A small area of northwest Illinois remains as abnormally dry due to some lingering concerns about subsoil moisture and groundwater levels in that area.

-MW-
The Illinois State Climatologist Office also contributed to this report.
The Iowa Climatology Bureau also contributed to this report.