A broad upper level trough remain in place over the Northeast this weekend. An upper level vortex over Hudson Bay in Canada continues to spin in little shortwaves into the base of the trough which will periodically pass through New England this weekend, providing enough lift in the atmosphere to sometimes form clouds or scattered showers. Each passing shortwave will breakdown any humidity in place and provide slightly cooler air behind it.
This Friday night is stating of nice, but we are tracking scattered showers and thunderstorms which have been moving east from NY state. These storms may come with some briefly heavy downpours later this evening and a rumble or two of thunder. Western MA appears to have the most unstable environment, but these cells will hold together long enough for a few scattered shower through midnight or shortly after. Skies may try to clear a bit behind these showers, but not for long. Lows will mainly hold in the 60′s over night.
A cold front will be pushing through New England Saturday. Saturday morning will see some clouds as well as the potential for a few more scattered showers or a thunderstorm. Not everyone will see them. This energy is part of the showers and storms currently over Lake Ontario and Erie. Westerly winds aloft will direct these scattered showers, clouds through New England during the morning. Drier air should follow in during the afternoon with skies becoming partly sunny and highs in the lwr 80′s with falling humidity. There is the potential for even a few scattered showers or a storm closer to the front in SE MA during the afternoon..which could affect the PMC riders. It is not a perfect Saturday, but there will be plenty of dry to enjoy, and by the afternoon our spirits will be right back up into weekend mode.
Dry cooler air in place Saturday night. By Sunday we will be tracking a stronger short wave barreling into the base of the trough and moving right through New England. Sunday will start off with plenty of sunshine, but clouds will quickly build to PM clouds and the risk of a few pop up scattered showers or storms will begin to pop in the afternoon…especially across the N & W in the late morning. SNE could see a brief shower or storm in the afternoon. Highs will be slightly cooler in the 70′s near 80 with a NW breeze. While some areas in SE MA will see the longest amount of sun…High could climb into the Lwr 80′s again. The PMC riders will have a marvelous ride Sunday with sunshine and low humidity, and temps rising into the Lwr-mid 70′s. Near 80 on the Cape by afternoon, but by then the riders will be on the boat back to Boston! These afternoon scattered showers will be part of a front, the leading edge of cooler drier air which will settle in for the start of the week.
Canadian High pressure with breezy NW winds on Monday will give plenty of sun on Monday with fair weather cumulus. The feel of fall will be in the air with high temps in the mid 70′s! Gorgeous crisp air. Sunshine in the 70′s will last through the midweek. As the upper flow starts to flatten, there will be the risk of some showers or storms Thursday into Friday. My Canadian dry air to follow with cooler air for the second weekend of August.
So not much has changed form the overall thinking. This upper level trough is here to stay for much of the month of August across the Great Lakes and Northeast which will supply seasonally average or below normal temps for much of the month. Sometimes a few showers, but the main thing we will take away is there will be no more 90 degree weather, and a definite lack of humidity! Sounds good to me!