Wind Whips Up Waves Then A Warm Up
CI love my alliterations. Windy weather today and tonight followed by a welcome warm up for the weekend. Winds will gust over 40 mph today with gusts close to 50 mph along Lake Michigan's shore. That has prompted the National Weather Service to issue a lakeshore flood warning until 7 pm this evening.
The O'Hare meteogram shows most models suggesting the strongest gusts will come this afternoon into the early evening hours. It will be a strong northerly wind that will run nearly the entire length of the lake. That "fetch" will help generate big waves along the southern shoreline of Lake Michigan.
Fetch is defined as "is the length of water over which a given wind has blown." Since the wind will be blowing parallel to the long north/south orientation of the lake it will cover quite a distance allowing the waves to build up and eventually crash on shore. Waves could reach heights of 10 to 14 feet with occasional waves up to 18 feet along Indiana's shoreline.
Here are some of the impacts possible according to Chicago's NWS office:
The large waves combined with record high lake levels will exacerbate already significant beach and shoreline erosion sustained in the past several months. In addition, low lying and flood prone areas including the Chicago lakefront path will likely be impacted. Water may cover roads near the lake, especially in the South Shore area of Chicago. Onlookers may be swept into the lake by the large waves.
The combination of cool temperatures and gusty winds will make for a raw end to April but May will start off milder. After 50s for highs today (with even 40s at the lakefront) we will see 60s Friday followed by 70s on Saturday.
We have been in a fairly persistent cool pattern for almost the entire month of April. For the first time since November we will end up with a month that was overall cooler than average. So far the month is coming in at about -.4° below average. While we have been unseasonably cool the west has been more than just unusually warm. Historic heat has hit the desert southwest. Southern California and Arizona have excessive heat warnings today with Phoenix expecting to top 100°. Las Vegas topped the century mark yesterday for a record high of 101°. That was the first 100° high ever for the month of April in that city.
There have been hints from the models that this pattern will change a bit in May. The long range three-month temperature probability forecasts from May through July and June through August both have the vast majority of the country outlooked for above average temperatures overall through this summer.
Here is my 7 day forecast:
Today: Showers early, cloudy, windy & cool High: 55 (48 Lakefront)
Friday: Partly to mostly sunny Low: 42 High: 62 (55 Lakefront)
Saturday: Partly to mostly cloudy, warmer, spotty shower? Low: 47 High: 73
Sunday: Partly to mostly sunny Low: 54 High: 66 (58 Lakeside)
Monday: Partly to mostly cloudy Low: 49 High: 59 (52 Lakefront)
Tuesday: Mostly cloudy, pm sct. showers Low: 41 High: 59 (54 Lakefront)
Wednesday: A.M. shower?, partly to mostly sunny Low: 45 High: 58