Heat Set to Ramp Back Up for New England

For the most part, Thursday will be a copy of the previous couple days. With no major weather features outside of surface high pressure around New England, it will be very seasonable with temperatures in the mid 70s to low 80s region-wide. Again, the onshore flow will keep the coast, particularly New Hampshire and Massachusetts, a bit cooler, but nothing notable. Scattered storms are again possible in the same general areas where they've popped up this week.

Overall, the persistent easterly flow will keep the more noticeable smoky and haze pushed across western New England today. Smoke is generally expected to continue to thin out by the end of the week and weekend for all of New England, but there's an inherent unpredictability to smoke forecasts, especially going out a few days.

As we head toward the weekend, high pressure will likely continue to dominate, keeping mostly to completely dry weather around. Toward the end of the week, an upper-level ridge will likely build over the east coast as surface high pressure continues to shift eastward. This will allow the onshore flow to turn more southerly, creating a warming trend.

Below: Upper-level height anomalies showing the ridge building over eastern Canada next week:

After a seasonable week with low humidity, temperatures and humidity will begin to climb with each day a notch warmer than the last starting Friday. Widespread mid 80s to 90s will likely return by Sunday. A large-scale ridge is expected to form across eastern Canada. This is consistent with a positive NAO (North Atlantic Oscillation) Index, which is expected to last through at least the middle of the month. This building ridge will support the rising temperatures over the next week.

Sunday will act as a transition day from the seasonable late-summer weather back toward full-on mid-summer heat and humidity. Sunday will likely see the beginning of a heat wave for New England's typical warm spots (Merrimack, Champlain and Connecticut River Valleys, namely). Elsewhere, temperatures are more likely to top out in the mid to upper 80s (heat waves require highs of at least 90°). Humidity will be turning up, however, it doesn't appear to be overly oppressive, hanging in the low to maybe mid 60s.

Below: Euro showing potential temperatures Sunday afternoon:

The continued ridge of high pressure will help steer a coastal storm system away from New England this weekend as well, keeping the region dry. This system, currently off the coast of the Carolinas, has a low chance to develop into a tropical system. It'll slowly move northeast, paralleling the coast before getting suppressed well south and east of New England.

Below: Euro showing potential weather Sunday morning, with the developing system passing well offshore of Cape Cod:

New England's heat will likely persist through the middle of next week, with widespread 90s across much of the region expected for Monday and Tuesday. New England's typical warm spots could push well into the 90s as well. Heat currently looks to press on into Wednesday, but a cold front will be approaching the region by then, so the timing of that front will determine whether or not Wednesday is another sizzler. This front will be looked to for relief from the heat, which it will likely provide to an extent. With large-scale ridging likely remaining in place, temperatures are favored to remain near or above average.

Overall, this is a dry pattern, with a large portion of New England expected to see less than a half inch of total rainfall over the next seven days. The higher terrain is expected to see the most precipitation as terrain-driven convection continues over the next couple days. More widespread showers and storms likely won't come until next week's cold front.

Below: Current seven-day precipitation outlook: