DAYS 1-5 (AUGUST 25-29)
When I made the comment that summers containing an unsettled June and July are often followed by a splendid August and September, I was worried that I might have to eat those words. Well, I’ve had to snack on them a few times as we never have really broken out of the unsettled pattern during the month of August either. Although we have had some nice days in there, and before the month is done, we will enjoy a few more. Despite that, we still have unsettled weather to endure, including and especially today (and maybe again before the end of the 5-day period). Focusing on today’s event first, the clouds that were slow to move in yesterday in advance of this system finally did so and thickened up overnight with the first warm frontal showers arriving mid to late evening. Since then the area has seen fairly widespread shower activity which will continue for much of the day today. The most persistent shower activity will occur in the eastern half of the WHW forecast area, basically I-495 belt east. Original optimism I had about longer rain-free periods for this region this afternoon has faded and it looks like it will be a pretty wet day overall, though areas to the west will still get a break in the activity more often as we head through the day. The warm front that approaches never really gets through here at all, so a broad onshore component to the wind flow will keep it on the cool side today despite the high humidity. While a couple of embedded thunderstorms can occur in these rounds of showers today and this evening, the parameters for strong to severe storms will not line up, so we won’t be needing to worry about tracking any of that. The region will receive a general 1 to 2 inches of rainfall from this event, with a few locations favoring southeastern MA possibly exceeding the 2 inch mark. A positive aspect of this is that flooding will be limited due to the more drawn-out timeline of heavier rainfall as opposed to having it all fall over a few hour’s time. The ground is already wet and the water tables are high, so it doesn’t take much to return to flooding status especially in prone areas. This system will not be in a hurry to exit tonight with the shower and isolated thunderstorm threat continuing into the overnight hours, but shifting to favor the I-95 belt eastward. There is somewhat better news for the weekend. While we’re not going to have a perfect summer weekend, the final one of August will feature OK weather. Dew points will remain fairly high Saturday with a slow drop-off from west to east as a frontal boundary pushes through. This front can still help to trigger isolated showers with thunderstorms a little more possible than today due to better heating and instability, but it’s not a set-up for widespread activity. If you have outdoor plans Saturday, just keep an eye on the sky and/or radar and have a plan in place just in case. For many of us, these plans will not be needed. Saturday evening, drier air finally makes its way in from the north, and on Sunday we’ll experience a cooler day with lower dew points, but the combination of a more northeasterly air flow and a weak disturbance aloft will create some additional clouds, and I cannot rule out a couple isolated pop up showers. Again though, this is nothing worth cancelling outdoor plans over. High pressure builds over the region with fair and comfortable weather Monday. Things begin to change again on Tuesday as the high slips away to the northeast and a trough approaches from the west. At the same time, western Atlantic tropical cyclone activity (forecast Hurricane Franklin) is expected to be occurring. The trough approaching is fully expected to help keep that system well offshore, but it will be close enough that increased ocean swells / surf and enhanced rip current risk takes place early next week. Keep this in mind if you have plans that include being at the coast. What I am not sure of yet is the timing of any rainfall threat associated with the approaching trough. Yesterday, my thought process was a wet Tuesday, but medium range guidance has slowed this system enough to make me lean toward a later arrival at this point, but will continue to monitor and refine the timing. For now, just anticipate that Tuesday won’t be as nice as Monday.
TODAY: Patchy fog early. Cloudy with widespread to numerous showers this morning, numerous to scattered showers this afternoon, including the slight chance of a thunderstorm. Highs 65-72. Dew point lower to middle 60s. Wind E-SE 5-15 MPH.
TONIGHT: Cloudy. Areas of fog. Showers likely with a slight chance of thunderstorms. Lows 60-67. Dew point lower to middle 60s. Wind SE-S up to 10 MPH.
SATURDAY: Partly sunny. Patchy fog early. Isolated midday and afternoon thunderstorms. Highs 72-79. Dew point middle to upper 60s through midday, lowering slowly thereafter. Wind S to SW increasing to 5-15 MPH, shifting to NW from west to east during the day.
SATURDAY NIGHT: Decreasing clouds. Fog patches in lower elevations. Lows 56-63. Dew point falling into 50s. Wind N 5-15 MPH, diminishing.
SUNDAY: Variably cloudy. Isolated showers possible. Dew point 50s. Highs 68-75. Wind NE 5-15 MPH.
SUNDAY NIGHT: Clearing. Lower elevation fog patches. Lows 52-59. Dew point lower 50s. Wind NW under 10 MPH.
MONDAY: Mostly sunny. Highs 71-78, coolest coast. Dew point 50s. Wind variable to SE up to 10 MPH.
MONDAY NIGHT: Mostly clear. Lows 57-64. Dew point 50s. Wind SE-S up to 10 MPH.
TUESDAY: Clouds return. Shower chance increases. Highs 72-79. Dew point climbs to 60+. Wind S 5-15 MPH.
DAYS 6-10 (AUGUST 30 – SEPTEMBER 3)
A trough moving through the region brings the chance of showers at least into August 30 (timing uncertain) before high pressure builds in for fair weather to end the month and start September.
DAYS 11-15 (SEPTEMBER 4-8)
Higher humidity and eventual shower chances as a trough approaches and moves in from west to east, favoring mid period.