Midwest Weekly Highlights - October 15-21, 2015

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Another Dry Week

Dry conditions persisted across the Midwest over the period, continuing what has been a dry October (Figure 1).  A few areas did see precipitation for the first time in October, however.  A soaking rain fell across eastern Iowa through the morning of October 21, the first rainfall over a half inch in the state this October.  Only a few isolated areas in the region received more than an inch of precipitation over the period.  Far northeastern Ohio was the only spot in the region with above normal precipitation (Figure 2).  Only a few other spots in eastern Iowa and Michigan had over half the normal amount of precipitation for the period (Figure 3).

The first snowfall of the season occurred during the week in the U.P. and northern Michigan, where 2-4 inches of snow fell on October 16-18 (Figure 4).  A few stations had between five and six inches.  The highest report was 6.0 inches in Kalkaska County.
 

Warmer to the West, Cooler in Ohio Valley

A divide in average temperatures was observed over the period, as the western half of the Midwest was warmer than normal while the Ohio Valley was cooler than normal (Figure 5).  Minnesota, Iowa and Missouri all were 1-4°F above normal for the period, with some areas 5-6°F above normal in the far western parts of those states.  High temperatures in these states were even warmer, with parts of western Iowa and Minnesota 7-10°F above normal (Figure 6).  Most of Wisconsin, Michigan and Illinois were near normal, with parts of southern Wisconsin and northern Illinois a few degrees above normal.  The U.P. of Michigan was below normal however, which helped facilitate the first lake effect snowfall event of the season.  The Ohio Valley was cooler than normal for the week due to well below normal low temperatures (Figure 7).  Kentucky and southern Ohio had low temperatures 7-10°F below normal.  Combined with closer to normal high temperatures, the Ohio Valley had average temperatures 4-7°F below normal over the period.
 

Drought Spreading Across the Midwest

Continued dry conditions in the Midwest have led to large precipitation departures across the region.  Over half of the region has received less than a quarter of the normal amount of precipitation through the first three weeks of October (Figure 8).  This led to more area classified in drought in the latest drought update from the National Drought Mitigation Center (Figure 9).  Over 11 percent of the region is now in moderate drought, compared to three and a half percent last week.  Every state except Ohio has at least some portion in drought.  The biggest additions to the moderate drought category were in Illinois, Indiana, Missouri and the U.P. of Michigan, with over 20 percent of Indiana and Missouri in moderate drought.
 

-BJP-