Temperatures

The period started in the wake of a strong cold front, which allowed unseasonably cold air to blanket the region. Temperatures averaged below normal to the east, with much of the Ohio River Valley 4-8°F below normal (Figure 1). Along the Mississippi River, temperatures were near normal for the week, and west of the Mississippi River they averaged generally 2-4°F above normal, though slightly more anomalous in western Minnesota.

Minimum temperatures were especially anomalous over the Ohio River Valley, where they averaged up to 10°F below normal for the week in certain locations (Figure 2). Elsewhere, they were near normal to slightly above normal in Minnesota.

Maximum temperatures followed a similar pattern, with temperatures 4-8°F below normal over Indiana, eastern Kentucky, and Ohio (Figure 3). Warmer air was already returning to locations west of the Mississippi River by mid-week, as maximum temperatures ended up 5-10°F above normal in Iowa, Minnesota, and western Missouri.

Precipitation/Severe Weather/Drought

Precipitation was minimal this week. There was nearly no precipitation west of the Mississippi River, and where there was—mainly the far northern portions of the region, southern Michigan, and Ohio—it was less than 50 percent of normal (Figure 4).

The lack of precipitation was evident by the minimal storm reports, which totaled less than 100 for the first time this season since the first week of meteorological spring (Figure 5). Most were associated with a weak wave of low pressure that took a southerly track along the Ohio River. There were 2 tornado reports, both of which were associated with a tornado that briefly touched down in Gibson County, Indiana.

There were minimal changes to the drought monitor since there was minimal precipitation. D2 conditions (severe drought) remained unchanged, and D0 (abnormally dry) and D1 (moderate drought) changed by less than 2 percent each, with some removal of D1 over northern Wisconsin (Figure 6).