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Dave Epstein | Forecast

Brilliant September weather is here

Jordyn Rourke read while sitting on the seawall at Brant Rock Beach in Marshfield.Craig F. Walker/Globe Staff

When I write these columns I like to find a little balance between telling you about the weather and my own personal opinion about it. Most of you know, for example, I do not enjoy hot weather, but with the upcoming forecast I think almost everybody’s going to agree this is pretty good stuff.

I started this morning as I often do with a walk and over the next five days there will be ample opportunity to enjoy these September mornings. The air is now comfortably mild and the humidity has dropped from yesterday. With highs this afternoon up near 80 and plenty of sunshine, the only minor issue will be a bit of a westerly breeze.


Warm temperatures Wednesday afternoon will be accompanied by full sunshine.NOAA

Even drier air will move in over the next couple of days. This is going to do a few things. First, it’ll give the sky a deeper darker blue. This is because the air is coming from Canada and there’s just less moisture and particulates so we end up with that brilliant September sky. The drier air will also lower the relative humidity.

This means that any moisture in the soil and in plants is easier to evaporate and transpire and increases our fire danger. The drought isn’t over and although we have had rain, the understory still has a lot of dead leaves and twigs ready for burn.

Dew points in the 40s Thursday bring a fall feeling to the air, especially in the morning.WeatherBELL

Remember, if you’re starting a lawn, or overseeding, or just growing some fall crops you’ll need to water. For those of you trying to reseed your lawn, watering lightly two to three times a day is best, so the seed doesn’t dry out.

Finally, lower dew points allow temperatures to fall once the sun goes down meaning a couple of crisp mornings here Thursday through Saturday morning. The weekend will be beautiful with Saturday’s highs in the 70s and Sunday approaching 80. There will be some cloudiness increasing later Sunday.


Depending on the timing of that weather system the clouds could come in before noon or hold off until late in the day. I’ll have more on that later this week.

Most areas will see temperatures in the 40s at sunrise Friday morning.Tropical Tidbits

There’s another kind of drought still going on in the tropics.

We are now several days past the peak of hurricane season but that doesn’t mean we still can’t get a major tropical system to impact the United States.

Yet, as of today, there’s only one lone system in the Atlantic that hurricane forecasters are watching. It’s been a tranquil year especially when you consider that La Niña years are often active. Most of the lack of activity is due to the higher-than-usual amounts of dry air down towards the tropics.

We’ll see if the second half of September and October bring any change to that pattern.

There is about a 50% chance a system in the southern Atlantic becomes a tropical storm later this week.NOAA