Sunday and Monday high temperatures held in the upper 60s in Grand Rapids, the first back-to-back days with highs in the 60s since June 2 – 3. The first 9 days of September were 3°cooler than average. So far, 2019 is 1.2° cooler than average and July has been the only month this year with warmer than average temperatures.
This is the 8-14 day temperature forecast from the Climate Prediction Center. You can see that most of the country is expected to be warmer than average with the warmest air relative to average in the Great Lakes and Northeast. We’ll be seeing a lot of days with high temperatures in the 70s and 80s over the next two weeks.
Here’s 90-degree days in G.R. by year. The graph starts with the very hot summer of 2012, when we had temperatures soar above 100° on July 5 and July 6. We had a 22-day stretch when the coolest high temp. was 86°. Then, two years later, we didn’t reach 90° all summer. The winters of 2013-14 and 2014-15 were quite cold and snowy. Last year we had 19 days with highs of 90° or better. This year we had 7 days of 90-degree heat…all in July and none warmer than 92°.
I’ve mentioned before on the blog that if you look at sea-surface temperatures, you see some similarities to late summer last year. First, there is still the big blob of relatively warm water south of Alaska and west of the U.S. West Coast. There’s also warm water off New England and E. Canada. That warm water helped Hurricane Dorian to remain an intense storm up into Nova Scotia, Canada. There is a mix of cooler than average and warmer than average water along the Equatorial Pacific. There’s also colder than average water over much of the Southern Hemisphere.
As we get into a winter pattern – starting in Oct. or early Nov. – upper level ridges tend to be more common over areas of warm water. So, that might be over Alaska and the West Coast and also over the western Atlantic – with an upper level trough in-between. It’s not like that all winter, but a significant portion of the winter. An upper level trough makes it easier to deliver cold into the northern U.S. During part of the last winter, we got the cold in S. Lower Michigan. At other times, the core of the cold stayed west of us in the Northern Plains.
Last year, we had a period of quite warm weather from Sept. 12-21, similar to what we are going to have this year. Those ten days were 8.5° warmer than average. The pattern stayed warm last year through early October. In fact, four of the first nine days of October saw high temperatures between 80° and 84°. Then we had a pattern change. It never got warmer than 60° after Oct. 11. We had 14.4″ of snow in November and a dismal 9% of possible sunshine. We had a break, with very little snow from Nov. 27 to Jan. 16. Then – wow! The Arctic cold came calling! G.R. got 28.9″ of snow in the last two weeks of Jan. From Jan. 25 thru Feb. 1 – it didn’t get warmer than 20°. We had a visit from the “Polar Vortex” with high (that’s right high!) temperatures of just +2° on 1/30 and +4° on 1/31. The cool pattern stuck around. We had measurable snow on April 10, 11, 14 and 15. We had scattered frost on 4/28, but (unlike the frost on 4/28/2012) in many cases, the blossoms on the fruit trees weren’t far enough along to do any significant damage.
We’ll come up with a winter forecast sometime toward late October, when we see how the early-season snowcover is building over Siberia and N. North America and we’ll see what sea-surface temps. are like along the Equator in the Pacific Ocean. In the meantime…enjoy this return of summerlike weather.
Also: Some meteorologists forecasting a very cold winter for the U.K. This website says the highest point on Grand Bahama Island is only 12 meters above sea level. I don’t know if this is right, but the Bahamas are low elevation islands, susceptible to having large parts of the islands inundated by storm surge during a significant hurricane.