Freezing low temperatures should be expected over Lower Michigan next week (first week of May)
I am expecting this summer, in Southwest Michigan to be near normal to slightly warmer than normal in the mean temperature but the frequency of very hot days, highs of 90F or more is likely to be less than normal.
Cooler temperatures are expected to prevail over southwest Michigan into through the first week of May. Milder conditions are expected to follow by mid month.
Why May This Change Be Happening?
As for why this may be happening I will look at the how the water temperatures in the Tropical Pacific have recently changed. Typically this sort of change forces large scale changes in the northern hemisphere wave pattern.
All of the data for the tables comes from either the Midwest Climate Center , xmACIS2, The National Hurricane Center and NOAA’s Physical Science Laboratory https://psl.noaa.gov/
Below are the wetter to 20 warmest summers
Now we will consider the driest warm summers
Here are the impacts for Southwest Michigan during those 20 warmest summers
Let’s look at the Palmer Drought Index compared with both the Soil Moisture Anomalies and Precipitation Anomalies.
I am expecting the summer of 2023, over southwest west Michigan to feature near normal temperatures when June, July and August’s mean temperatures are averaged together. I am also expecting this summer to be wetter than normal across all of Southwest Michigan
I have updated my summer forecast for southwest Michigan based on the impact of warmer sea surface temperature over most of oceans in the more recent 30 years. Curiously the outcome, from my updated analogs would suggest a near normal temperature outcome and but a continued wet weather pattern into the summer months.
First severe storm event of 2023 for Southwest Michigan
It is worth noting for my top 3 warmest winters, the frost depth stayed under 6″.
Below is a table that shows the top 10 warmest winters since 1999, and the maximum frost depth. Note that except for 2016 and 2020, the frost depth was no greater than 7.5″.
Top 10 Warmest Grandville Winters since 1999
So, why was the frost depth so deep in 2016, even through it was relatively warm winter? It’s a function how persistent the cold temperatures were, in combination with the snow depth.
In 2016, through it was an overall warm winter, when the frost depth got to 11.5 inches in mid February the snow depth stayed under 3″. Meanwhile the 7 day running mean temperature fell to 16.5 degrees. This year our lowest 7 day running mean temperature was 17.8 degrees, not really all that much warmer than in 2016, however this year the snow depth during that time was between 12 and 16 inches. The point being, to get a deep frost depth you need less than 5″ of snow depth and a 7 day running mean temperature below 20 degrees.
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