Warm, comfortable and dry weekend ahead in the wake of Wednesday/Thursday downpours which leave the area still dealing with a moisture deficit; Friday’s 91-degree high was the 4th in a row—the most consecutive 90s so early here in 46 years
Tom Skilling, Bill Snyder, and Jennifer Kohnke
No t-storms in the Chicago area today—dew point drop and stabilizing east winds off Lake Michigan have forced storm development well west of the area. Dry, warm weekend ahead with sharp late Monday cold front passage. Possible “pneumonia front” to usher strong, temp-dropping full fetch (i.e., full length of Lake Michigan) “NNE” winds into Chicago which drop Tuesday and Wednesday temps below normal before warming’s back next Thursday and Friday.
The air mass has dried since yesterday but managed a 4th consecutive 90-degree Chicago high temp and a 6th consecutive above normal temp. Lake breezes produced significant cooling on area beaches while highs as hot as 96 occurred at Oswego and 95 was reported at Warrenville and Plainfield. Shoreline temps at 73 on the Lake Forest, Lake Michigan shoreline. It’s the 7th day lake breezes have cooled the shoreline—even though water temps have crept up to 62 at Ohio Street Beach. The average southern Lake Michigan water temp is up 5.5 degrees in the past week.
A BEAUTIFUL WEEKEND AHEAD: WARM TEMPERATURES, BUT NOT RAIN OF SUBSTANCE IN SIGHT THROUGH THE COMING WEEK
In fact, over the coming two weeks, rainfall is predicted to average, based on a average across a series of medium range forecast models, less than half (45% normal).
Even with yesterday’s selective rains which produced Chicago O’Hare’s heaviest rain (0.89”) in the two months since late March, RAINFALL HERE remains WELL BELOW NORMAL.
The graphics show how dew points—a measure of moisture—are to remain low over the coming week and drop further after the vigorous cold front passes late Monday, ushering a strong, Lake Michigan wave-generating/temp dropping “NNE” flow into the area.
The series of surface forecast maps show how high pressure is to drop southward into the Chicago area with that cold frontal passage setting the stage for the full fetch “NNE” winds expected to begin late Monday and persist Tuesday and Wednesday next week.
A significant late week temp rebound is predicted Thursday and Friday — only to be followed by what looks from this distance in time to be another cool-down next weekend and subsequent warming in the week which follows.
THERE WAS NO RAIN nor were there thunderstorms in the Chicago area Friday. Dew points — a measure of atmospheric moisture — have dropped from yesterday’s muggy mid 60 to 70-degree levels to the upper 40s in parts of the Chicago area. That was expected and represents a SIGNIFICANT DROP in moisture levels. Little wonder NO t-storms have bubbled up over the Chicago area. Isolated t-storm formations was limited to western Illinois instead. And, we’re back in the dry pattern which has dominated the the area since just beyond the first week in April.
Even with yesterday’s 0.89” of rain at O’Hare — MORE than occurred at that site the entire month of May and the heaviest rain to occur there in 2 months — rainfall totals have been abysmally low: just 42% normal. O’Hare has only recorded 3.61” since April 1st, compared to a normal of 8.55” during that period. That’s a rainfall deficit of 4.89.”
