100% sunny Wednesday with a 25 degree lakeshore to inland temp spread. 58 Lake Forest & Waukegan to 83 Tinley Park. May’s opening 10 days among the driest 25% since 1871. But more clouds and showers in our future later this week. Rain chances at 70% for Friday, flow off Lake Michigan plus clouds suggest cool weekend ahead.

The skies were all but cloud-free Wednesday and temps responded in a bit way. You can’t do much better than 100% of our possible sun–and that’s what happened Wednesday.

May’s produced some blockbuster rainfalls–but in areas south and west of Chicago. The 3+” t-storm downpours in harder hit south and southwest suburbs this past weekend were great examples. But interestingly, in Chicago itself, May’s opening 10 days rank among the driest 22% of all Mays over the past 151 years with only 0.29″ on the books to date compared too the normal 1.03″ to date.

Wednesday was another gorgeous day–and temps away from Lake Michigan responded big time, reaching the upper 70s and low 80s. While temps hit 82 at Joliet and Peotone and 83 at Tinley Park, mid-afternoon lakeshore air temps held to 58 at Lake Forest and 59 at Waukegan Harbor and Zion.

Coming days will see increased clouds. Though Thursday should see temps surge broadly to the low 80s inland with mixed sun making for another beautiful day. Rain chances surge Friday and could include scattered t-storms as winds off Lake Michigan cut into daytime warming.

A broad and persistent northward flow of Gulf moisture is predicted to increase clouds–particularly Thursday night and through the weekend. Dew points will be surging to the 60s Friday and into the weekend. Rain chances are to take off–but currently modeling suggest the widest coverage rainfall looks likely to occur Friday, thinning out om frequency and coverage Saturday–only to increase Sat night, Sunday and Sunday night.

Models offer rainfall estimates of 0.6″ to as much as 1.50″ by Monday morning–though rainfall is to arrive in waves.

I wouldn’t be surprised to see cool winds off Lake Michigan interact with all the moisture in the air to produce lakeside foggy spells over the coming weekend. And strengthening northeast winds with a tightening pressure gradient over the weekend is likely to take a toll temps–particularly along Lake Michigan–where weekend highs could struggle to make the upper 50s and may stay in the low 50s Sunday.


TONIGHT: Partly cloudy, not quite as cool. Temps modestly above seasonable norms. Low 55—but upper 40s cooler inland locations.

THURSDAY: Partly sunny, warm again away from the immediate lakeshore. Highs 82 there—but mid 60s on area beaches.

THURSDAY NIGHT: Clouding over. Scattered showers develop over 30 to 40% of the area before daybreak. Milder. Low 61.

FRIDAY: Showery—some with thunder, especially southerly sections–Note as warm but noticeably more humid. High 70—but closer to 60 on the lakeshore.

SATURDAY: Cloudy and turning breezy from the east/northeast with elevated humidities and some haze and fog, especially along Lake Michigan. Drizzle and scattered showers. High 69—but 59 on area beaches.

SATURDAY NIGHT AND SUNDAY: Showers increase in frequency and coverage. Breezy and cooler. Low Saturday night 54. High Sunday 59—but low to mid 50s along Lake Michigan.

MONDAY: Clouds breaks allow some sun to emerge. Less wind and milder. High 72—but low 60s lakeshore.

TUESDAY & WEDNESDAY: A good deal of sunshine, seasonably mild inland but with cooler lake breezes. High Tuesday 71. Wednesday’s high 70.