Midwest Weekly Highlights - October 1-7, 2015

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Cooler Start to October

Average temperatures were cooler than normal across the western reaches of the region to start October.  Temperatures from Wisconsin through Iowa and Missouri were 2-5°F below normal for the period, with areas in western Missouri up to 6°F below normal (Figure 1).  Average temperatures were closer to normal across the Ohio Valley, where temperatures were in the upper 50s to low 60s (Figure 2).  Far northwest Minnesota and southeast Kentucky had average temperatures a few degrees above normal.

While average temperatures were generally near to slightly below normal, high and low temperatures were at other ends of the spectrum for the period.  High temperatures averaged below normal for most of the region (Figure 3), while low temperatures were largely above normal in the eastern half of the region (Figure 4). Average low temperatures remained above freezing for most of the upper Midwest despite nearing the median first fall freeze date in most areas (Figure 5).
 

Very Dry Week

Dry conditions were common across the region to start October, as almost the entire western half of the region had no precipitation (Figure 6).  The wettest areas were in southeast Kentucky where more than an inch of rain fell over the period.  Most of the eastern half of the region saw less than half an inch of precipitation.  Despite the dry conditions, departures were less than an inch below normal (Figure 7), as most of the region typically receives less than inch of precipitation during the first week of October (Figure 8).
 

First Fall Freezes Happening Later in Upper Midwest

Warm September temperatures in the Midwest have kept cold overnight temperatures away, leaving many areas in the Upper Midwest without their first fall freeze (Figure 9).  Northern Minnesota and Wisconsin have already seen their first freezes of the season in late September, with some coming during the first week of October.  In many cases, the first freezes were near or later than the median date of the first fall freeze.  Southern Minnesota, Iowa, northern Illinois and southern Wisconsin have yet to see a freeze this year, and will likely be later than the median dates for the season.  Median dates for the first fall freeze in these areas are during the first ten days of October (Figure 10).
 

Drought Added to Missouri

Dry conditions over the past month in Missouri led to a new area of moderate drought in the north central part of the state in the latest drought monitor (Figure 11).  After one of the wettest summers on record, most of the state has seen precipitation values 2-4 inches below normal since September 1 (Figure 12).  Meanwhile, above normal precipitation in Kentucky lessened drought concerns as moderate drought was removed from the central part of the state.  An isolated area of moderate drought is still in place across southern Indiana and southwest Wisconsin, however, and nearly a quarter of the region is abnormally dry.

-BJP-