The weather to start July has been sultry and significantly above average in terms of temperature and below average in terms of rainfall. It looks as though we’ll get a break in the heat this weekend, but then what happens for the rest of July and into August?
In the short run, it’s likely that we heat up again next week with at least two, perhaps three, 90-degree days for many locations. I don’t see the same level of humidity or the heat lasting as long, but it’s going to feel quite hot and typically summery.
There also won’t be much in the way of rainfall after the showers Friday bring the end to the early July heat wave. This dry pattern is not atypical; July and August don’t bring much in the way of rain, and what rain we do receive mainly comes from scattered showers and thunderstorms.
Very warm so far
Friday marks the 30th day in which Boston has reached 80 degrees or higher this year. If this pace continues through September, we could come close to the highest number of 80-degree days in a year, which is 83 set back in 1983. It would be an awfully warm September if that happened.
Which pattern dominates?
There’s basically three types of patterns we could see for the rest of the summer. The first would be a strong ridge across the East Coast that would provide warmer and more humid conditions.
The second pattern would be more of a zonal flow, where weather basically moves west to east across the country and typically provides average summer conditions. The final pattern features a trough, or a region of somewhat low atmospheric pressure, across the East that would provide cooler and generally wetter conditions than average.
Throughout the past six weeks, the predominant pattern has been a ridge, which has kept the area warmer and drier. It looks like this continues through the middle of July before we may see a week or two where a trough brings less heat and more showers.
This doesn’t mean it’s going to rain and be cold. It’s just a way of saying the chances of 90-degree weather and drier-than-average conditions fall, while the odds of showers increase.
August is a bit of a question. First, summer long-range patterns are often hard to predict. The atmosphere is somewhat innocuous with lots of general warmth in the Northern Hemisphere. It’s not until the end of the month that significantly cool air will develop across Canada and start putting pressure on the jet stream to move south. This is why August often brings those hazy, warm, and muggy conditions we call the dog days.
Here’s the bottom line on what lies ahead for us. There are going to be several more 90-degree days, but I do see some breaks in the heat between. What’s been an overall dry pattern since the middle of spring is likely to continue.
The one thing we will have to watch for over the next couple of months is any tropical systems tracking close to us. These storms, while relatively brief, would bring more significant weather to the region.
As I like to remind folks, it’s been 27 years since the last hurricane reached the shores of New England. It’s only a matter of time before it happens again.