COMMENTARY
Before going forward through the coming 5 days, a quick look back at the last 2. Bermuda High weather pattern, same general set-up with high pressure off the US East Coast pumping very warm to hot and humid air into the region. But let’s look at Boston. There were a couple striking differences between the two days in the same location that are the type of thing that is not always too easy to forecast, even in the short term, although I got one and kind of missed the other. At Logan Airport, where the city’s official observations are taken, there was some abundant cloud cover to start the day out Thursday with a disturbance moving through the region. Eventually more sunshine was observed. The southwesterly air flow was weak enough so that a sea breeze developed and prevented the temperature from reaching 90, while the dew point stayed quite high at 70+, oppressive humidity. Fast forward to Friday. There was plenty more sunshine for a good part of the day with only some limited cumulus clouds around late in the day, and then a shadow from the anvil of distant thunderstorms blotting the sun out in the evening. But the day featured the temperature climbing a few degrees above 90 when the wind, which was a little more notable, shifted to west and northwest, a direction often noted for a down-slope effect that not only heats the air up heading out to the airport, but also dries it out, so while the temperature over-achieved expectation, the dew point, which sat in the oppressive 70s prior, dropped into the still humid but slightly more tolerable 60s. This was a classic example of this phenomenon, which was definitely under-estimated by yours truly.
DAYS 1-5 (AUGUST 8-12)
Our stretch of very warm to hot, humid weather continues this weekend, with today being the more humid but least hot of the two, while there’s a slight reversal of this on Sunday with a bit more heat but a bit less humidity, accomplished by a southwesterly air flow today shifting to more westerly on Sunday. Isolated to scattered shower and thunderstorm chances are greatest today, with the potential for one somewhere in eastern coastal areas as a disturbance departs the region first thing in the morning, and the chance returning in the afternoon and early evening in response to diurnal heating. Additionally, a small disturbance may trigger a few more nighttime storms favoring areas to the south of I-90. This is followed by a quieter day in terms of storm chances Sunday, with just a remote risk for a pop-up afternoon storm. Monday continues the theme of very warm to hot and moderate to high humidity, sans storm chances as the atmosphere will be more stable. We then look to our west for a disturbance to pass through between later Tuesday and early Wednesday with another opportunity for showers and thunderstorms and a slight downward trend in the temperature while humidity says somewhat elevated.One other note, you’ll notice a hazier look to the sky at times the next few days – a little bit today, a little more Sunday morning, and potentially considerably more early next week, coming from high altitude wildfire smoke from the US Pacific Northwest.
TODAY: A sun / cloud mix. A shower or thunderstorm possible early morning favoring eastern areas, and anywhere in the afternoon. Highs 85-92 except 78-85 coastal areas. Dew point 68+. Wind SW up to 10 MPH but with potential sea breezes in all coastal areas.
TONIGHT: Partly cloudy. A shower or thunderstorm is possible early north of I-90. A batch of showers and thunderstorms may travel across some areas mainly south of I-90 late evening or overnight. Patchy fog. Lows 67-74. Dew point 65+. Wind SW up to 10 MPH.
SUNDAY: More sun than clouds. An isolated afternoon shower or thunderstorm possible. Highs 84-91 except 77-84 coastal areas. Dew point 68+ but may drop somewhat during the day. Wind W 5-15 MPH.
SUNDAY NIGHT: Mostly clear. Patchy fog. Lows 67-74. Dew point 65+. Wind SW up to 10 MPH.
MONDAY: Sunshine dominates. Highs 83-90 but cooler South Coast / Cape Cod. Dew point 60+. Wind WSW 5-15 MPH.
MONDAY NIGHT: Partly cloudy. Lows 68-75. Dewpoint 65+. Wind SW 5-15 MPH.
TUESDAY: Variably cloudy. Showers and thunderstorms probable. Highs 81-88 except cooler South Coast / Cape Cod. Dew point 70+. Wind SW 10-20 MPH.
TUESDAY NIGHT: Mostly cloudy. Shower chances with a possible thunderstorm. Fog patches form overnight. Lows 65-72. Dew point 65+. Wind SW up to 10 MPH.
WEDNESDAY: A sun / cloud mix with a possible shower favoring the morning to midday hours. Highs 81-88. Dew point drops toward 60. Wind W 5-15 MPH.
DAYS 6-10 (AUGUST 13-17)
West to east flow with a more up-and-down temperature pattern evolving. Best chance of unsettled weather from a passing disturbance will be early in the period before mainly dry weather takes over.
DAYS 11-15 (AUGUST 18-22)
A shower or thunderstorm possible a couple times with passing disturbances / frontal systems in a west to east flow. Temperature trend is down a little to near to slightly below normal.