Mar 10 | Weekly Climate Review & Weather Forecast
Climatological spring began much as winter ended, with milder temperatures. 7-day average temps ranged from the mid-30s in northern Illinois to the low 50s in southern Illinois, 3 to 8 degrees above normal for early March. NOAA released official numbers for February, which was the 12th warmest on record statewide, and climatological winter, which was the 8th warmest on record statewide. One consequence of the persistently mild weather over the last 6 to 8 weeks has been an early start to spring phenology in our perennial plants. The National Phenology Network estimates spring phenology is about 2-3 weeks ahead of schedule in most of Illinois.
March has also started on the wet side across the state, following wetter than normal months in February and January. In fact, the entire state has been wetter than normal to date in 2023, with parts of northern and southern Illinois experiencing 150% and 200% of normal year-to-date precipitation. This week followed suit and brought more wet conditions to our state. 7-day precipitation totals ranged from around half an inch around the Quad Cities to over 2 inches in parts of east-central Illinois. The northern part of the state even saw measurable snowfall later this week, including accumulations of 6 to 10 inches in Winnebago, Boone, and McHenry Counties.
Near- to medium-term forecasts are indicating a weather regime shift to cooler conditions across the eastern U.S. The 8 to 14 day outlook that takes us through the 3rd week of March is leaning to likely below normal temperatures, with highs this next week forecasted in the mid to upper 30s across much of the state. Lows will likely regularly dip below freezing at least in central and northern Illinois, so some of those early advancing perennials may need some assistance so as not to get nipped by the cold. The good news is the cooler weather will slow the rapid progression of spring and hopefully reduce our risk of spring freeze damage later this season. Meanwhile, forecasts and outlooks through the end of the month keep a somewhat active storm track, but with closer to normal precipitation. Forecasted totals of the next 7 days range from around 1 inch in southern Illinois to around a quarter of an inch in northern Illinois. The cooler air means the northern half of the state has better odds to see additional snowfall this and next week. It’s likely we’ll get more snow in March than we had in either January or February.