The change to refreshing, dry air unfolded this morning but it took all day for lower humidity to arrive on the outer Cape. In fact, a couple of downpours occurred there early this afternoon along the frontal boundary. It still turned out to be a warm August day with highs of 83-88. Deeper into the afternoon, a batch of puffy clouds across northern New England expanded into north central MA and it spread out over the Boston area early this evening. As the night progresses, this cloud deck should disappear and the temperatures will decline to the upper 50s in the cooler outlying locations to the upper 60s in the larger urban centers. A terrific Tuesday is on tap with highs in the middle 80s except closer to the upper 70s to near 80 at most of the beaches as a sea breeze blows at 6-12 mph much of the day. High tide occurs just before 4pm as sunshine prevails most of the day. There could be some streamers of feathery cloudiness visible throughout the day with a few scattered flat fair-weather clouds. A weak bubble of high pressure will shift across the region during the day and move offshore tomorrow night. This cell will set up offshore resulting in more of a southeast to southerly breeze on Wednesday resulting in the return of higher humidity. There will be some added clouds to the sky on Wednesday but sunshine should still rule.
Looking ahead, a digging short wave of energy will evolve into a closed upper level low pressure system digging across the Great Lakes toward NY. This feature will trigger a wave of low pressure that will shift eastward and draw moist air from the south. Consequently, expect a spell of showery and muggy weather starting sometime on Thursday afternoon and probably not concluding until late Saturday night or Sunday morning. It will not be continuously raining but we will be vulnerable to showers and some storms at any time through that period. Daytime temperatures may not rise much above the lower 80s due to more widespread and persistent cloudiness. The night will be warm and sticky with foogy spots and lows in the upper 60s. The system and its attendant cold front will sweep offshore during the middle portion of the weekend resulting in clearing probably after the peak of the Perseid Meteor Showers Saturday night. If all goes well, we will be able to view the leftovers on Sunday night as another mass of fresh air flows in from Canada. This may set the stage for a few splendid days the first half of next week.
Tropical Storm Ernesto intensified today and he might blossom into a Cat 1 Hurricane before making landfall on the Yucatan Peninsula. This system is unlikely to threaten the USA. To keep up-to-date on the happenings in the tropics, logon to the National Hurricane Center.
Melissa Mack delivers her AccuWeather Forecast in the morning and I shall return later in the day for Todd Gutner.
Make it a great Tuesday!