Outlook for summer 2017: Cool start, warm finish

South Haven, Lake Michigan
A boat on Lake Michigan near South Haven on June 11, 2017. Courtesy: http://crated.com/ericdush


GRAND RAPIDS, Mich. (WOOD) — The unofficial start of summer is here — and after a tumultuous winter and despite a cool start, it’s looking pretty normal.

The forecast is a result of a balance of many factors, but one of the most reliable is that years similar to this one also had normal summers. Those similar years are called “analog years.”

“We take a look at the factors that matter in terms of long-range weather and we try and look back through history to see which years had similar patterns,” Storm Team 8 Chief Meteorologist Bill Steffen explained.

This year features a weak to nonexistent El Nino and a warm Gulf of Mexico. Usually a set up like this calls for a pretty standard summer.

WHAT IS NORMAL?

Summer officially begins this year on June 21. Astronomically, it lasts for a full 93 days, although the summer warmth usually lingers around West Michigan for 120 days.

Our hottest days are usually in July with the first 90-degree day gracing our part of the state around mid-June.

Our rainiest month is May, which usually sees close to 4 inches of rain. August is the driest of the summer months, but not by a wide margin. August usually sees close to 3.5 inches of rain.

Rain this summer will be very hit-and-miss. Bill Steffen says not to expect everyone to get the same rain totals.

Even though our typical highs are in the 70s and low 80s through the summer, we usually launch to 90 degrees or hotter nine or  10 times each summer. Recently, we’ve had a huge fluctuation from year to year in terms of the number of 90-degree days achieved.

Number of times we’ve hit 90 degrees or hotter in previous years in Grand Rapids

SUMMER WARMTH WILL LIKELY START SLOWLY

This April was the second wettest on average nationally and the sixth wettest on record for West Michigan. All of that water in the ground was great for areas of drought, but it means much of the Midwest will be slower to warm this season.

“Obviously, when you have wet ground, the sun doesn’t spend as much of its energy heating air — it has to evaporate water. So when the ground is wet, you don’t get quiet as hot,” Steffen said.

June will likely start on a cool note

June is one of our sunniest months, which will help evaporate excess water. July and August should be pretty close to normal.

NATIONALLY LIKELY BE STORMIER THAN USUAL

So far the nation is off to a stormier start than usual, ranking in the upper 75 percentile.

National severe weather reports this year via Storm Prediction Center

The cool waters of Lake Michigan have created a nice buffer, protecting Michigan from a lot of these severe storms. The protective bubble is pretty evident in this storm report map from 2017 so far.

Severe wind, hail, and tornado reports for 2017 nationally

Bill Steffen said that once we finally warm up, we will likely see storm activity increase in West Michigan.

“I think the Gulf of Mexico being warm is a good moisture source. We have cool air across Canada and a pretty good contrast going on,” he said.

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