SYRACUSE, NY (WSYR-TV)
The Storm Team Summer Outlook for 2020 is calling for near normal temperatures with between 7 and 10 90 degree days and near normal rainfall in Syracuse and Central New York.
When making a summer forecast we typically like to look back at recent weather trends during the current Spring and even the past winter to find clues as to what is coming for the upcoming summer.
This year, I started by diving into warm winters (December through March) then cool springs (April/May) just like we’ve just gone through. Unfortunately, that was a tall order and I could only find one year that fit those criteria: 1996-97. I like to use a larger sample size so lets move the Summer of 1997 off to the side for the time being.
I also decided to look at slightly below normal winter snowfalls. Now that winter seems to be over (finally) we ended up at 87.6” which puts us about 3 feet below our normal seasonal snowfall but not into the top 10 least snowy winters. Again, not much help here as those years were split almost evenly between cooler, warmer and near normal summers.
What if we narrow things down a bit to just very cool Mays? This May, so far, has fit the bill. As of Wednesday we were running about 6 degrees below normal and even a warm up this weekend and next week may not be enough to erase all that deficit.
I looked closely at the Top 20 coolest Mays over the last 70 years (since records have been kept at the airport). To end up on that list you needed to be at least two degrees below normal for the month.
11 out of the 20 years ended up with summer temperatures near normal during the months of June, July and August. The average number of 90 degree days was just under 8 days which is close to the long term average of 9 days.
Of course there are some exceptions to the Cool Mays rule. Six years had below normal summer temperatures and only three ended up above normal. In fact, two of the more recent very cool Mays, 2002 and 2005, ended up with very hot summers. 2005 turned out to be our hottest summer.
As far as rainfall was concerned, a majority of those same Mays were close to normal in their summer precipitation which is why we leaned that way for our forecast. Rainfall forecasts for the summer are always tricky given pop up, slow moving thunderstorms that can cause rainfall to vary quite a bit across Central New York.
Oh, and that Summer of 1997? It ended up with slightly below normal temperatures (-.6 F for the three months) near normal 90 degree days (a total of 7) and slightly below normal rainfall (-2.18”)