Monthly Overview - January 2018

 

Big Temperature Swings

The Midwest saw big temperature swings in January. The month began with frigid temperatures across the region. Hundreds of record low daily temperatures were set across the region, particularly in the first three days of the month. Average temperatures for the first seven days of January were well below normal across the region with most areas at least 15°F below normal and a bulls eye on the Illinois-Indiana border had temperatures more than 25°F below normal (Figure 1). Northwest Minnesota was only 5°F to 10°F below normal for the first week. The middle two weeks of the month saw rapid swings to warm and cold followed by very warm conditions in the last 10 days of the month. Temperatures across the Midwest were 5°F to 10°F above normal for this 10-day period (Figure 2). There were 1350 record high daily temperatures and 747 record low daily temperatures during the month with most of the record lows occurring in the first three days of the month and the records highs occurring later, many from the 10th to the 12th or from the 20th to the 27th. On average, temperatures were closer to normal for January with near-normal temperatures in Minnesota, Wisconsin, and Michigan and slightly below-normal temperatures (1° to 4°F below normal) for the remaining parts of the region (Figure 3).
 

Drier than Normal

Conditions in January were mostly on the dry side in the Midwest, particularly in west central Minnesota where less than a quarter inch of precipitation fell (Figure 4) and Kentucky where deficits up to 2.00 inches below normal were noted along the Tennessee border (Figure 5). A few locations had monthly totals that failed to reach 50% of normal and west central Minnesota had less than 25% of normal for the month (Figure 6). The areas with above-normal precipitation were mostly from Iowa to Upper Michigan. A couple hundred daily record high values were recorded in January with most occurring from the 11th to the 13th or the 22nd to the 23rd. Every Midwest state had at least eight stations with record precipitation days.
 

Snow Totals

Snow was below normal in January for most areas of the region (Figure 7). A swath from northwest Iowa to northwest Wisconsin had above normal totals mostly due to the storm on the 22nd and 23rd. Storm totals peaked from 12 to 17 inches. The swath of above-normal snow along the Ohio River and into central Ohio was from an event on the 13th which dropped 2 to 6 inches in this area. Lake-effect snows downwind of the Great Lakes was a mixed bag with higher values off the southern tip of Lake Michigan and in parts of Upper Michigan while there were lower values in parts of Upper Michigan and across most of Lower Michigan, particularly in northern Lower Michigan.
 

Drought Slightly Expands

The generally dry conditions led to a slight expansion of drought in the Midwest in January (Figure 8). The area of extreme drought in south central Missouri remained steady but areas of moderate drought expanded during the month. The percentage of the region in drought increased from about 9% to 12% from the 2nd to the 30th. At the end of the month, about 60% of Missouri was in drought while areas in southwest Illinois, southeast Iowa, and northern Minnesota were also in drought.
 

Severe Thunderstorms

Severe thunderstorms made an appearance in the Midwest on just two days. On the 21st (Figure 9), two tornadoes were reported along with a handful of severe wind reports in Missouri. Damage was primarily trees and limbs downed. The following day saw severe weather further east (Figure 10), large hail was reported in Illinois and Kentucky and severe winds were reported in Indiana, Ohio, and Kentucky. The couple dozen wind reports included several noting tree damage and a few noting damage to barns in Ohio.
 

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The Iowa Climatology Bureau also contributed to this report.
The Minnesota State Climatology Office also contributed to this report.