The Cold Is Back
Below normal temperatures returned to the Midwest to start the month of February
(Figure 1) as an Arctic high pressure system took over for most of the week. A fresh snowpack also helped reflect more sunlight during the day and aided radiational cooling overnight. Mean temperatures were 4-9° F below normal across Iowa, Wisconsin, Michigan and the Arrowhead of Minnesota. Farther south, temperatures were near 3° F below normal as snow-free ground helped temperatures stay warmer. Temperatures would have been even cooler than normal if it wasn’t for a very warm day on February 7 that melted away a good portion of the snow pack across the central Midwest. Areas with little or no snowpack even had above normal high temperatures over the period (Figure 2) thanks in part to the warm up.
Snowy Start to February
After a mainly quiet and dry start to winter, a couple of winter storms dumped large amounts of snowfall across the Midwest to start the month of February (Figure 3). Heavy snow fell across northern Illinois, Indiana and Ohio as well as southern Michigan on February 1-2. A second system moved through on February 3-4 that added to snow totals. All of this snow brought liquid equivalent precipitation numbers of 0.5-1.5 inches across most of the southern half of the Midwest (Figure 4). This led to 3-5 times more than normal precipitation
(Figure 5) throughout most of Iowa, northern Missouri and northern Illinois. Much drier conditions were seen in northern Wisconsin, the U.P. of Michigan and northern Minnesota. However, these areas usually do not receive much precipitation during this time of year, and only saw departures of a few tenths of an inch below normal (Figure 6).
Snowstorm and Blizzard January 31-February 2
A strong winter storm dropped large amounts of snow on the Midwest, resulting in Chicago seeing one of its largest snowfall events in recorded history. The storm’s forecast evolved greatly as the storm neared as explained by the meteorologists at the National Weather Service-Louisville. Read our full write up on the storm in the Climate Watch for January 22-31.
Snowy Follow-Up February 3-4
Another system followed a blast of arctic air on February 3 in southern Minnesota, dropping 2-4 inches of snow. An isolated strong band of snow then moved along the Iowa-Missouri border into central Illinois and northern Indiana on February 4, dropping over 6 inches of snow in some spots along the Iowa-Missouri border (Figure 7). While these bursts of snow had less liquid equivalent precipitation (Figure 8), cooler temperatures caused higher snow-to-liquid equivalent ratios, leading to decent snow totals.
Drought Concerns Lessened By Snowstorm
With areas in Iowa and northern Illinois receiving precipitation near an inch or more than normal this week, the National Drought Monitor receded abnormally dry conditions across most of the central Midwest (Figure 9). Some abnormally dry areas remain in southern Wisconsin. Almost all of Minnesota is still in the abnormally dry category with moderate drought conditions in parts of the northwest corner of the state. While precipitation fell on Kentucky and the Missouri Bootheel this week, it was only enough to keep these areas near normal for the week, leaving drought conditions in a stasis for now. Most of the Midwest continues to see a dry winter (Figure 10) with below normal precipitation since November 1, 2014.