The rains of the past few days have moved us from the 2nd driest October on record to the 13th driest October on record. The statewide total is now 1.24 inches, 2″ below average.
The Illinois State Water Survey soil moisture network shows a nice recovery at the 2 and 4-inch depths. However, dry conditions remain at the 8-inch depth at most locations. This should be good news for winter wheat and pasture.
Fraction of water by volume at 2 inches for October 28, 2015. I know, odd units to understand. For most of our soils, values less than 0.3 are dry, values of 0.3 to 0.4 are good, and values above 0.4 are wet. Havana in the center of the state is our special case – a sandy soil that holds little water.
Here is the rainfall map for the past 7 days. Most of the rain in Illinois has come in the last 2 days of that mapping period. In fact, almost all the rain in October for Illinois has fallen in the last 2 days.
Most of Illinois was in the two lighter shades of green, indicating rainfall amount of between 0.5 and 1.5 inches. There is a hole in southwestern Illinois (blue) were rainfall amounts were less than 0.5 inches. Higher amounts of 2 or more inches just missed Illinois, and fell across the border in Kentucky and southern Indiana.
It looks like we have one last shot of rain in October on Saturday.
Click to enlarge.
As of this morning, the statewide average precipitation in Illinois was 0.34 inches. That makes it the second driest October on record. However, the forecast for Tuesday will move us down in the rankings. In the meantime, here is where we stand for dry Octobers:
||Percent of Average
The US Drought Monitor has placed portions of Illinois in a moderate drought this week.
USDM for Illinois. Click to enlarge.
Over the weekend, most areas of the state saw their first taste of 32 degrees or colder. Here are the maps from the Midwestern Regional Climate Center showing that the almost the entire state was covered. A few places in the Chicago area may have escaped thanks to the so-called Urban Heat Island (UHI) – lots of warm surfaces like roads, asphalt parking lots, roofs, and waste heat from buildings. For example, O’Hare AP reached 33 degrees. Meanwhile, Mt. Carroll in northwest Illinois reported 20 degrees on October 18. Now that’s cold.