Midwest Weekly Highlights - January 8-14, 2018

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Warmer Weather Briefly Returns

A reprieve from bitterly cold temperatures was found across most of the Midwest during the week (Figure 1).  Temperatures were 1-4°F above normal across Ohio, Indiana, eastern Kentucky, Michigan, southern Wisconsin and northern Illinois.  Areas in Iowa and Minnesota remained below normal, however.  Most of Missouri and the western Ohio River Valley were near normal.

A warm air mass dominated most the period before a storm moved through the region.  Several hundred daily high maximum and minimum temperature records were broken or tied during a very warm stretch from January 10-12 (Figure 2).  Nearly 300 daily records were broken for January 11 alone (Figure 3).  Maximum temperatures reached the 40s and 50s across a majority of the Midwest through the morning of January 11, with 60s in portions of Missouri and Kentucky (Figure 4).

By January 13-14, temperatures dived well below normal in the region (Figure 5).  Large east to west temperature differences were observed as a cold front moved through the region beginning on January 11, with an arctic air mass diving southward.  The coldest observed minimum temperature in the Midwest through the morning of January 12 (Figure 6) was -39°F in Embarrass, MN (St. Louis County), while the warmest was 53°F in Circleville, OH (Pickaway County), a 92°F difference.  Several dozen daily low maximum and minimum temperature records were broken during the last few days of the period as colder weather returned (Figure 7).
 

Wetter and Snowier for Many

Precipitation came in larger amounts during the period as a major winter storm moved through (Figure 8).  More than an inch of precipitation fell across most of Kentucky, southern Indiana and Ohio, while more than a half inch fell in Missouri, Michigan, and northern Minnesota.  This was more than twice the normal amount in many of those areas (Figure 9).  Drier weather was common across Iowa, southern Minnesota, Illinois and southern Wisconsin.

Moderate amounts of snowfall accompanied the storm system, as colder air filled in (Figure 10).  Four to six inches of snowfall was common across northern Minnesota through the morning of January 11 (Figure 11), while several inches fell across the rest of the Upper Midwest through the morning of January 12 (Figure 12).  The Ohio River Valley then received 2-4 inches through the morning of January 13, with several areas in eastern Ohio receiving more than six inches (Figure 13).
 

-BJP-