Midwest Overview - October 2012

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Precipitation

October monthly precipitation totals ranged from only 0.5" to 1" in parts of the northern Midwest to 8" to 10" in northeastern Ohio (Figure 1). A majority of the region received anywhere from 3" to 5" of precipitation during the month of October. These precipitation totals are within an inch of normal for much of the region (Figure 2), with the exception of parts of Minnesota, Missouri, and Kentucky that were 1" to 2" below normal and portions of Wisconsin, Michigan, Illinois, Indiana, and Ohio that were 1" to 6" above normal. The significant precipitation in northeastern Ohio resulted from Hurricane Sandy making landfall on the East Coast of the United States. During this event, this region received 3" to 8" of precipitation (Figure 3). To read more about the impacts of Hurricane Sandy on the Midwest, read the Midwest Climate Watch Week 4 Highlights.

Based on preliminary data, average statewide monthly precipitation totals show that seven out of the nine Midwest states experienced above normal precipitation for October (Figure 4). Minnesota and Missouri were the only two states to experience average statewide precipitation that was below normal. As a whole, the Midwest region received above normal precipitation during October.

There were several locations across the Midwest that received some snowfall during the month of October (Figure 5). Northern Minnesota received the most snowfall, with 3" to 8" falling throughout the month. Upper Michigan also received anywhere from 2" to 5" in October. Portions of Ohio and Kentucky also received snowfall at the end of the month as a result of the remnants of Hurricane Sandy. Totals ranged from 0.1" to 1.5" in Ohio, while eastern Kentucky received anywhere from 0.1" to 4" of snowfall. In the higher elevations of Kentucky (over 2,000 feet), more localized snowfall totals ranged from 12" to 18" (Figure 6). The snowfall received in Minnesota was above average for the month of October, but the snowfall in Upper Michigan was very close to the long-term normal

(Figure 7). As expected, the snowfall totals in the eastern Midwest from the remnants of Hurricane Sandy were above normal for this region for this time of year.

There were just over 840 daily precipitation records set throughout the month, with the majority occurring in Iowa, Wisconsin, and Illinois (Figure 8). There were several monthly precipitation records set as well, mainly between October 13th-15th in Iowa, Wisconsin, and Illinois. There were just over 70 daily snowfall records set and a few monthly snowfall records.
 

Temperature

For the second month in a row, below normal average temperatures were widespread across the Midwest. Departures ranged from 1°F to 5°F below normal (Figure 9). Based on preliminary data, average statewide monthly temperature data shows that all nine Midwest states, and the Midwest region as a whole, experienced below normal temperatures (Figure 10). The largest temperature departures were in Iowa (-2.6°F), Missouri (-2.2°F), and Minnesota (-2.1°F).

As a result of the cooler than normal temperatures, several stations reported their first 32°F freeze during the month of October. Many stations experienced their first 32°F freeze when it is climatologically expected (based on the median date), however several stations in Iowa, Illinois, Indiana, and Ohio experienced an earlier first 32°F freeze than normal in September (Figure 11). Many stations in the central United States also reported their first 28°F freeze during October, however many in Minnesota, Iowa, and Wisconsin first reported 28°F in September, which is generally earlier than the long-term average (Figure 12).

Several daily temperature records were set throughout the month, with a mixture of record lows and record highs. The record highs were mainly set later in the month, while the record lows were more numerous at the start of the month and in the last 5 days (Figure 13).

Drought and Harvest Progress

Despite the near normal precipitation for much of the region, drought conditions saw little improvement during the month of October (Figure 14). Currently, almost 56% of the region is still experiencing some level of drought, compared to the almost 70% at the beginning of the month. Drought conditions worsened throughout October for some of the states that experienced near to below normal precipitation during October (mainly Minnesota and Iowa). However according to Harry Hillaker, Iowa State Climatologist, lower evaporation rates so far this fall has allowed for some soil moisture recharge. The largest improvement in drought conditions throughout October occurred in Ohio, Indiana, and Michigan.

All nine Midwest states made significant progress on the harvesting of corn and soybeans during the month of October. By the end of October, there are several states that are are nearing the end of their corn and soybean harvest. Missouri, Minnesota, Kentucky, Iowa, and Illinois report over 90% of the corn harvested, which is significantly above the 5-year average for most of these states. Soybeans are completely harvested in Minnesota and Wisconsin, and Iowa, Illinois, and Michigan have almost completed soybean harvesting as well (Table 1).

Near Record Low Lake Levels

According to the US Army Corps of Engineers (USACE), monthly lake wide mean levels on Lake Michigan-Huron and Lake Superior were near record lows during the month of October. By the end of October, the mean lake wide level of Lake Michigan-Huron was 576.6 feet, which is within 1.5 inches of the record October low set back in 1964 and 1965 and only about 6 inches above the all-time record low lake level of 576 feet in March 1964. By the end of October, Lake Superior was 15 inches below the long-term October average.

The near-record low levels in Lake Michigan-Huron and Lake Superior are a result of the low snowfall in the 2011-2012 season and the hot, dry summer experienced throughout the region, which led to high evaporation rates off of the lakes. Some of the impacts of the low lake levels include commercial navigation (decrease the amount of load they can carry and reduced access to harbors), increased need for dredging, and recreational boating (may not be able to reach certain points on the lakes). Whether or not Lake Michigan-Huron and Lake Superior hit record lows in the coming months will really depend on the weather over the next few months. According to the USACE, if the region was to see a winter similar to last winter, the potential is very real for record lows to occur. However, if the region returns to more normal winter and spring regime, then the threat of record lows may not be as high.

Fall Season To Date

As we head into November, the last month of meteorological fall, the fall season so far has been cooler than normal (Figure 15) and much of the region has experienced near to above normal precipitation (Figure 16). This is in great contrast to the meteorological summer (June through August), which experienced unseasonably warm temperatures and widespread below normal precipitation (Figure 17).

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The Iowa Climatology Bureau also contributed to this report.
The Kentucky Climate Center also contributed to this report.
The Missouri Climate Center also contributed to this report.