Gradually Getting Back To Normal
Patchy Frost Possible Again Tonight
Monday's high of 52° at O'Hare marked the third straight day with highs in the 50s. Yesterday's high is a more typical temperature for late March. Northerly Isle and Waukegan could only muster a high of 48°.
Even with plenty of sunshine today it won't be much warmer. Highs should reach into the lower to middle 50s for most of us but just upper 40s along the lakefront again. Average highs in the middle of May are near 70°.
A breeze off of Lake Michigan will keep us 15° to 20° below average again today. There will be a wind off the lake through the weekend. We will manage to slowly but surely warm up but that onshore breeze means cooler conditions lakeside all the way into Sunday.
Southern Lake Michigan's surface water temperatures remain chilly even for this time of the year. The remote sensing plot below shows 40s and even some pockets of 30s far from shore. Cloud cover obscured the measurements closer in but buoys and other observations indicated lower to middle 50s right along the lakefront. No wonder a breeze off of this water keeps us so cool in May.
Protect those plants again tonight because we might not be done with May frost just yet. Skies should be clear tonight to once again set the stage for at least some patchy light frost outside of the metropolitan area of Chicago. Lows in our colder spots will dip in to the middle to upper 30s.
The lows tonight will be around 10° to 15° below average. This cool pattern covers a good portion of the country. The Midwest and most areas east of the Rockies will be well below average early Wednesday.
Time for some good temperature news. We do see a slow but steady warm up that should peak early this weekend. Highs by as early as Friday might tag 70° in a few spots. 70s should be more widespread on Saturday. The GFS model has us fall back into the 50s on Sunday before we bounce back into the 60s on Monday.
Waiting For More May Rain
There could be a spotty sprinkle or two on Thursday but most of this week will be sunny and dry. The GFS model suggests some much needed rain could come as we get into a more unsettled pattern Sunday and into early next week. O'Hare is down just over an inch of rain from average for May and down over five inches below average since March 1st.
A drought-busting drenching type rain could be coming according to the GFS model. The total precipitation accumulation forecast through Monday morning brings around an inch and a half of rain to our northern suburbs and over three inches south of the city. This would definitely put a dent in the ongoing drought in portions of northern Illinois.
Warmer Pattern Signal Gets Stronger
We will warm back above average by the weekend and this mild pattern could stick around through the following weekend. The long range temperature probability forecasts favor us for above average temperatures overall as we approach the end of May. The latest 6-10 day forecast still has us outlooked for above average temperatures overall from May 16th through May 20th but the probabilities are low. The 8-14 day temperature probability forecast keeps above average overall from May 18th through May 24th. The highest probabilities in this second forecast reach into the Chicago area. Average highs for this period are in the lower 70s.
The even longer range Subseasonal Experiment (SubX) temperature anomaly forecast has been consistently calling for a cooler pattern recently but the latest forecasts now favor the Chicago area for near normal temperatures for the end of May and start of June. The average highs for this period are in the middle 70s. The temperature anomaly forecast for the week ending May 28th has us outlooked to be about average overall. The forecast for the following week ending on June 4th has Chicago about average overall too.
Positive Sign For More May Rain
Both the longer range precipitation probability forecasts once again favor us for a more active pattern that could help alleviate the drought in portions of the Chicago area. The forecasts have Chicago, the Midwest and most of the middle of the country outlooked for above average precipitation. The latest 6-10 day forecast has Chicago favored for above average precipitation from May 16th through May 20th. The longer range 8-14 day forecast also has us favored for above average precipitation overall from May 18th through May 24th.
Here is my 7 day forecast:
Today: Mostly sunny, cool High: 54 (48 lakeside)
Wednesday: Sunny skies, milder Low: 38 High: 61 (cooler lakeside)
Thursday: Partly to mostly sunny Low: 44 High: 66 (cooler lakeside)
Friday: Partly to mostly sunny Low: 46 High: 68 (cooler lakeside)
Saturday: Partly to mostly sunny, shower possible late Low: 49 High: 70 (cooler lakeside)
Sunday: Mostly cloudy, showers & sct. thunderstorms Low: 50 High: 66 (cooler lakeside)
Monday: Mostly cloudy, showers & sct. thunderstorms Low: 55 High: 72