It’s Chicago’s “lake wind” season, a situation underscored by Friday and Saturday’s “NE” then “SE” winds

It’s a fact of life in Chicago during spring: winds blow off Lake Michigan nearly half the time. And since the lake waters have yet to recover from the chill of winter, those winds tend to be nippy.

The northeast flow which is to dominate Friday and Friday night arrived before daybreak with the passage of a cold front. That lake flow all but assures city and lakeshore residents they can forget a second consecutive day of 60-degree temperatures.

Rather than the 62-degree high recorded Thursday—the city’s ninth day of 60-degree or warmer temperatures this year—Friday highs are likely to reach no higher than the mid 50s inland while lakeside locations struggle just to make it to the mid to upper 40s. And, as the northeast flow strengthens Friday afternoon and evening, the expectation is afternoon and evening readings may trend lower, even in areas away from the lake.

Resurging warmth, southerly winds to propel Sunday highs into the 70s, making it the warmest Easter in 4 years

The upcoming Easter weekend is to be far from a complete meteorological loss. Precipitation is to be all but non-existent—at least not until late Sunday night and Monday. And temperatures, which are to remain cool near Lake Michigan Saturday, are to take off Sunday as southerly winds take hold.

Cool Friday – Weekend Warm-up ahead

Cool Canadian high pressure will settle over the Chicago area Friday. A northeast breeze will keep readings along the lake front in the 40’s while farther inland afternoon temperatures will reach into the lower or middle 50’s. Easterly flow will persist into the morning hours Saturday and then as winds become more southerly in the afternoon temperatures will peak in the middle 60’s- some 10 to 12 degrees warmer than Thursday.

Southwesterly flow will strengthen Saturday night and continue Easter Sunday. Despite increasing cloudiness, Sunday’s afternoon highs will reach the middle 70’s –  one of the warmest readings so far this year. With the approach of a cold front from the west, showers and thunderstorms could spread into the Chicago area late in the day and continue Sunday night. Periodic showers and thunderstorms and mild temperatures will probably continue Monday before the cold front finally passes through our area Monday night.

ASK TOM WHY: How many past Good Fridays have experienced rain or snow?

Dear Tom,

How many past Good Fridays have experienced rain or snow?

— Michael K. Garrison,
Chicago

Dear Michael,

Good Fridays do show a bias toward precipitation. With the help of Chicago weather historian and climatologist Frank Wachowski, we checked the weather on 143 Good Fridays dating to 1871. Measurable precipitation has occurred in 73 years, or 51 percent of the days, at a time of the year when the daily climatological expectation for precipitation is about 40 percent. When traces of rain and snow are added to the mix, the percentage jumps to 64 percent as compared with an expectation of 56 percent. The last rain to fall on Good Friday was April 22, 2011, when more than half an inch soaked the city.