From 60° Sunday To Snow By Tuesday
Lake Breeze & Big Temp Range Today
After three straight days with below average temperatures we should recover a few degrees today. There will be a wide range of high temperatures because of a brisk breeze off the lake. Near the lakeshore highs will struggle to climb to 50° and further inland highs will warm to near 60°. The average highs for today's date are 60°.
Snow Still In Forecast Next Week
The GFS model has been consistently suggesting snowfall for next week. There are two chances for some slushy snow. The first is late Monday night into Tuesday and the second is late Wednesday into early Thursday.
We average 1.2" of snow for the month of April. The last significant April snow here was just two years ago when 2.5" of snow fell at O'Hare on the 27th of the month. It was the latest accumulating snow we had seen here in more than 25 years.
The accumulated snowfall meteogram for O'Hare shows a range of snowfall for early Tuesday morning. Models lay out as little as a dusting to nearly three inches.
The GFS model still keeps the swath of heavier snow south of the city into central Illinois. The model run below is through Thursday morning. The bulk of the snow shown here is for Tuesday with additional light amounts late Wednesday into Thursday. The snowfall amounts taper off along the lakeshore in the city because the transition from rain to snow will be delayed a bit because of a wind off of Lake Michigan.
The European model had been more stingy with the snow in earlier runs but is now spitting out more snow than the GFS model. The Euro is now spitting out around 2" near the Wisconsin state line to nearly 9" in northwest Indiana. It is suggesting nearly a half a foot of snow in the city. The snow should be slushy with accumulations coming more quickly on grassy surfaces. Complicating the snowfall forecast will be the wind off the lake, a relatively warm ground and snowfall rates. Stay tuned as these numbers will be refined in coming forecasts.
Warm Up Before The Fall
The hourly temperature meteogram compares many different forecast models. We will warm up to near 60° this weekend. Highs fall into the 40s for Tuesday and Wednesday before warming back up to near 60° by the end of next week.
The temperature anomaly forecast suggests Tuesday will be the coldest day of the week and the coldest since the start of April. It has northern Illinois and Indiana will be between 10° to nearly 20° below average.
Cool End To April
The longer range temperature probability forecasts still favor Chicago for cooler than average temperatures overall through the end of the month. The latest 6-10 day forecast has us outlooked for below average temperatures overall from April 22nd through April 26th with northern Illinois inside the bullseye of the highest probabilities. The 8-14 day temperature probability forecast has us favored for below average temperatures overall from April 24th through April 30th too. Average highs in Chicago for late April are in the lower to middle 60s.
The even longer range Subseasonal Experiment (SubX) temperature anomaly forecast is signaling a cooler than average end to April and a return to around average for the start of May. The temperature anomaly forecast for the week ending April 30th has us outlooked to be a bit below average overall. The forecast for the following week ending on May 7th has Chicago bouncing back to about average overall. Average highs by the start of May are in the lower 60s.
Dry Pattern Developing?
The long range precipitation probability forecasts suggest we may move into a drier pattern for the end of the month. The latest 6-10 day forecast still has Chicago favored for below average precipitation from April 22nd through April 26th. The longer range 8-14 day forecast has most of us outlooked for below average precipitation overall from April 24th through April 30th too.
Here is my 7 day forecast:
Today: Partly to mostly cloudy, spotty shower possible south High: 58 (50 lakeside)
Sunday: Partly/mostly cloudy, spotty pm shower possible Low: 39 High: 60 (cooler lakeside)
Monday: Sunny early then clouds increase, rain late Low: 41 High: 60 (cooler lakeside)
Tuesday: Rain and snow (some accumulation possible), mostly cloudy Low: 37 High: 41
Wednesday: Partly to mostly cloudy, rain and snow possible late Low: 32 High: 46
Thursday: Partly to mostly sunny Low: 38 High: 58
Friday: Partly to mostly cloudy, rain possible late Low: 40 High: 60