9:42AM
DAYS 1-5 (JULY 21-25)
One more day of relatively low humidity as dew points start below 60 under the influence of an air mass that had its origins north of the border some time ago. But this is all about to change as this high pressure area gives way to a new pattern, the arrival of which will be marked by a complex low pressure area, one spinning in the Ohio Valley influencing a coastal low that will move north then hook northwest into the northern Mid Atlantic, sending a tail of tropical moisture into New England during Sunday with waves of showers. With a little wind shear in place, typical for these types of systems, we’ll have to watch for any heavier downpours/thunderstorms becoming capable of producing locally strong to damaging wind gusts in the form of either a brief burst of wind coming down from above, or even a small and short-lived, relatively weak tornado. And there is no need to panic over hearing that term. This pattern can and has produced these before. An extreme case in this situation would be the Revere tornado a few years back. In just about all cases, anything that occurs will be less than that, track-wise and damage-wise. But where it is a summer weekend and many people are about the area, it’s always wiser to know even the most remote possibility and be aware of what to do, just in case. Sunday has been pre-termed “washout” by many, but this will not be the case. There will be rain-free periods as well, and some locations may go hours between showers. As we start the new week, the Monday through Wednesday period will see fewer showers and storms, coverage-wise, as the main axis of activity is going to be pushed to the west of the region by retrograding, or westward-moving, high pressure from the western Atlantic. So while I can’t rule out showers/storms any of these days, and if any happen to occur at your location, it can rain very hard for a time, but the vast majority of the time at any given location will be rain-free, just warm and quite humid, as we continue to be dominated by a southerly flow of tropical air. Forecast details…
TODAY: Sun dominant early, clouds dominant later. More humid by late day. Highs 77-86, coolest coastal areas. Wind light E to SE.
TONIGHT: Clouding over. Showers arriving south to north overnight. Humid. Lows 63-70. Wind SE to S 5-15 MPH.
SUNDAY: Mostly cloudy to partly sunny. Showers likely. Chance of thunderstorms. Downpours and locally strong wind gusts possible. Very humid. Highs 74-82. Wind SE to S 10-20 MPH, higher gusts especially coastal areas where a few gusts to or over 30 MPH are possible.
SUNDAY NIGHT: Partly cloudy. Isolated showers. Very humid. Lows 68-75. Wind S 5-15 MPH.
MONDAY: Partly sunny. Scattered to isolated showers and possible thunderstorms. Very humid. Highs 78-86, coolest South Coast.
TUESDAY & WEDNESDAY: Partly cloudy. Isolated showers and thunderstorms mainly late day. Humid. Lows from the middle 60s to lower 70s. Highs from the upper 70s to upper 80s, coolest Cape Cod, warmest interior valleys.
DAYS 6-10 (JULY 26-30)
The overall large scale pattern, as mentioned previously, will feature a low pressure trough around the Midwest and Great Lakes and high pressure off the US East Coast. As the strength and position of the ridge fluctuates, it will help determine days with higher shower and thunderstorm threats. A higher threat is expected sometime during the July 26-27 period before it drops off again on the July 28-29 weekend, possibly to return July 30. As previously mentioned, this is not the type of pattern with washed-out days, just one that presents opportunities for showers/storms at times, prompting one to keep a close eye on weather is they have outdoor plans. Temperatures during this time are expected to run at or slightly above seasonal averages.
DAYS 11-15 (JULY 31-AUGUST 4)
Not seeing any major pattern shifts during this period as well.