60s Coming But Snow Possible Too
Brisk Breeze Off Lake
A cool breeze off the lake will keep our highs around or just a bit above average today. Today's highs should top out in the middle 40s but closer to 40° along the lake. Average highs for this time of the year are around 43°. March is running just over 2° above average so far but it is set to soar much higher above normal next week.
First 60s Of Spring
We'll warm from 40s today to near 50° tomorrow and then 60° or warmer by early next week. The average first date of a 60° high is February 19th so we are running a little behind schedule. Temperatures tumble Thursday and Friday as we fall back into the 40s.
The temperature anomaly forecast has not changed much for Wednesday. It has temperatures running between 10° to 30° above average from Texas to Michigan. Northern Illinois could be 25° to nearly 30° above average Wednesday morning. That would mean lows Wednesday morning in the 50s. The record high minimum temperature for that date is 52°.
Some Light Spring Snow Coming?
The latest GFS model's meteogram keeps things quiet until Wednesday. Showers and possible a few isolated thunderstorms may develop by the middle of the week. The model shows some light snow late Thursday into Friday with another chance for light snow early Sunday following some rain on Saturday. This is still several days away so I suspect the timing and amounts will change in future forecasts. Snow in March is no surprise though since we average 5.6" for the month.
The accumulated snowfall forecast meteogram shows a few models suggesting light snow late Friday. The early forecast range is around a third of an inch to around a half an inch.
The GFS model's snowfall accumulation forecast run out through Saturday shows a swath of moderate snow downstate with light amounts reaching into northern Illinois. This is still subject to change but supports a change to a colder pattern by next weekend.
Temperatures Falling To Around Average
It looks likely that next week will be above average with a few days well above average. The longer range temperature probability forecasts seem to suggest the following week won't be quite as mild. The latest 6-10 day temperature probability forecast has us outlooked for above average temperature overall from March 11th through March 15th. The longer range 8-14 day forecast favors us for a return to about average temperatures overall from March 13th through March 19th. That period begins a week from Saturday and continues into the following Friday.
The even longer range Subseasonal Experiment (SubX) forecast has a mild pattern for March continuing right through nearly the end of the month. The forecast for the week ending March 19th keeps us milder than average overall. Chicago and northern Illinois is favored for more above average temperatures overall for the following week ending on March 26th.
Precipitation Probabilities Falling
While we are still favored for above average precipitation overall during the middle of March, the probabilities are dropping. This could be signaling a drier pattern by the end of the month. The 6-10 day forecast favors us for above average precipitation overall from March 11th through March 15th. The longer range 8-14 day forecast has us outlooked for above average precipitation overall from March 13th through March 19th. The risk for spring flooding is above average for many area rivers. More on that below.
The Climate Prediction Center's seasonal forecast for spring suggests a mild and moist pattern overall here. The temperature probability forecast for the months of March, April and May have us outlooked for above average temperatures overall. The precipitation probability forecast for the same period has us outlooked for above average precipitation overall.
Spring Flood Risk Forecast
The National Weather Service considers many risk factors for spring flooding. They include snow cover, soil moisture, and current river conditions.
"A significant snow cover with high water content can increase the chances of flooding once warmer weather melts the snow. Elevated soil moisture conditions reduce the amount of rainfall that is soaked up by the ground and increase the amount of water that then runs off into area streams. Above average river levels reduce the river rise required to reach flood stage, while below average river levels would require an increased amount of river rise to reach flood stage."
Their latest forecast suggests the flood risk is above average for many of our area rivers. The Des Plaines and Fox rivers in particular need to be watched closely.
Here is my 7 day forecast:
Today: Mostly sunny, a bit breezy High: 45 (cooler near the lake)
Sunday: Partly to mostly sunny Low: 27 High: 54 (cooler near the lake)
Monday: Mostly sunny Low: 40 High: 61
Tuesday: Partly to mostly sunny Low: 46 High: 63
Wednesday: Mostly cloudy, sct. showers & t-storms Low: 52 High: 63
Thursday: Partly to mostly cloudy, sct. showers Low: 48 High: 55 (cooler near the lake)
Friday: Partly to mostly sunny Low: 38 High: 47