Forecast for the Rest of the Summer

Bill's Blog

The rest of the summer should continue warmer than average. Rainfall is always quite variable in the summer, but overall, average rainfall is expected.

The first week of July was about as warm in Grand Rapids (avg. temp. 79.4°) as it was in Mobile, Alabama (79.8°). We had the sunniest June ever and the combination of above average sunshine, warmer than average temperatures and light winds has boosted water temperatures to near record level (on Tuesday, the surface water temp. reached 83° at the South Haven buoy and the surface water temp. of inland Reeds Lake reached 85°.

Radar at 1:25 pm June 10, 2020 – Showing Strong to Severe Storms

Rainfall has been below average in most areas since the start of meteorological summer on June 1. Grand Rapids has had 2.86″ of rain since 6/1 and that’s 1.74″ below average. Kalamazoo has had 2.22″ and that’s 2.07″ below average. Despite the below average rainfall, many rivers are still a touch above average flow. As I type this, the flow on the Grand River at Grand Rapids is at 2,930 cubic feet per second, compared to the average flow for 7/8 of 2,590 cfs. The radar pic. above is from the strong to severe thunderstorms that caused a significant amount of wind damage in S. Lower Michigan on June 10.

Drought monitor – July 2

Also, despite the dry pattern, there is no significant drought in Michigan due to the cool and wet pattern we had for much of the spring. This map will be updated tomorrow (Thu. July 9). Much of the “Corn Belt” and the growing areas east of the Rockies have ample soil moisture. Many crops in the West (apples in Washington State, vegetables in California) are irrigated.

Graphic from the Grand Rapids National Weather Service
Graphic from G.R. NWS – Warm Summers Follow Warm Winters

The graphic above is from the G.R. National Weather Service. When we have a warm winter, we are very likely to have an above average number of 90-degree days in the following summer. That’s what’s happening again this summer and this time Muskegon and the lakeshore is getting into the act – because of the warmer water of Lake Michigan and the light wind pattern keeping the lake-effect cooling west of the Muskegon Airport at times.

Number of 90-degree days in Grand Rapids

The number of 90-degree days in Grand Rapids varies quite a bit from year-to-year. The average is nine, but we’ve gone from none (1951 & 2014) to 37 (1988). This year we are up to 10, and I think we have a good shot at reaching 20 or more.

Sea Surface Temperature Anomaly Map

This is the latest map showing sea surface temperature anomaly (difference from average). Yellow, orange and red areas are warmer than average and blue areas are colder than average. Note the warmer than average water in the “hurricane belt” from Africa to Florida. This favors an above average number of hurricanes this summer and fall in the Atlantic/Caribbean/Gulf of Mexico.

Second, look at the plume of colder than average water temperatures along the Equator west of S. American (and west of Africa). Here the wind has increased, stirring up colder water from below the surface. This is called “La Nina”. Here’s what a typlical La Nina means for the following winter:

La Nina Winter Pattern for North America

Just this much would lead you to think that next winter will be at least a little cooler and snowier than last winter in Lower Michigan. It’s too early to make a winter forecast. We usually do that in late October.

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