DAYS 1-5 (SEPTEMBER 13-17)

An unsettled stretch of weather is at hand. This part of the forecast is a little more pessimistic sounding than I had been during the last few updates. First, the pre-dawn hours today featured a fast-moving batch of thunderstorms crossing southern NH and northern MA from west to east, a little complex of storms that was fairly well-forecast by short-range guidance. The last little hang back tail, a small meso-scale low pressure area, is crossing Metro Boston as of 7 a.m. in the form of showers and a couple downpours, but this will all be offshore very soon and other than one additional shower or two coming eastward across similar areas into mid morning, today is going to feature improvement and a nice afternoon. The small bubble of high pressure bringing the drier air in will be centered to our north as it moves to the east and the wind will shift to the east Tuesday ahead of an approaching warm front, with more clouds returning. This warm front brings the chance of showers Tuesday night and introduces warm and humid air to the region for Wednesday, a day we’ll have to watch for a shower and thunderstorm threat as a cold front approaches. I still feel the timing of this front may be late enough that we may escape the potential for stronger storms as the activity will arrive during the evening and night, but it will be something to keep an eye on. Different from my previous forecast is a more unsettled look for Thursday and Friday as the front doesn’t really get that far to the south and east before coming to a halt, and the low pressure area that I alluded to for next weekend is expected to organize and have an impact sooner than that on Friday, so lots of clouds and occasional wet weather can be expected later in the week as well, with the wettest day expected to be Friday as it stands now.

TODAY: Mostly cloudy start with additional showers especially MA and southern NH into mid morning, then sun and passing clouds. Highs 72-79. Wind variable becoming NW 5-15 MPH.

TONIGHT: Mostly clear. Fog patches in lower elevations. Lows 55-62. Wind NW under 10 MPH becoming variable.

TUESDAY: Sunshine followed by increasing clouds. Highs 68-75. Wind variable becoming E up to 10 MPH.

TUESDAY NIGHT: Cloudy. Chance of showers. Lows 58-65. Wind SE up to 10 MPH.

WEDNESDAY: Partly sunny. Highs 78-85. Humid – dew point upper 60s. Wind SW 10-20 MPH.

WEDNESDAY NIGHT: Variably cloudy. Chance of showers/thunderstorms. Lows 63-70. Wind SW 5-15 MPH becoming variable.

THURSDAY: Mostly cloudy. Chance of showers. Highs 70-77. Wind variable 5-15 MPH.

THURSDAY NIGHT: Mostly cloudy. Showers likely. Patchy fog. Lows 60-67. Wind variable to E 5-15 MPH.

FRIDAY: Cloudy. Chance of rain. Highs 67-74. Wind E 5-15 MPH.

DAYS 6-10 (SEPTEMBER 18-22)

With the earlier arrival of low pressure and things not too bogged down I am a little more optimistic today about the weather for next weekend (September 18-19) with improving conditions. After that high pressure may park off the Atlantic Coast for a warmer interlude while we again watch moisture to the south, but this is a very low confidence forecast.

DAYS 11-15 (SEPTEMBER 23-27)

General west-to-east flow resumes with up and down temperatures and limited shower chances but still need to watch the western tropical Atlantic for potentially putting a system somewhere near or off the East Coast.