New England's Next Heat Wave is on the Way

High pressure will continue to dominate New England's weather this weekend, keeping completely dry and warm conditions around. An upper-level ridge will build over the east coast as surface high pressure continues to shift eastward. This will allow this week's persistent onshore flow to turn more southerly, continuing the warming trend that began yesterday. Dry air will likely mix down to the surface today, keeping humidity levels low with dew points in the 50s this afternoon.

Below: High temperatures (1st image) and dew point values (2nd image) early this afternoon. This sets up a beautiful summer Saturday:

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, which is currently near the southeast coast, once had a moderate chance to develop into a tropical system, though that is now very unlikely. It'll slowly move east northeast before getting suppressed well south and east of New England today.

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°). This will come as the surface high pressure shifts south of New England at the same time an upper-level ridge continues to build into New England.

Below: GFS showing potential temperatures Sunday afternoon:

New England's heat will persist through the middle of next week, with widespread 90s across much of the region expected for Monday through Wednesday. Tuesday looks to be the peak of the heat as temperatures aloft will reach their climax. Temperatures at the low levels (2,500 to 5,000 feet above sea level) will likely push into the upper 60s to 70s, supporting widespread 90s at the surface across much of New England.

Below: Height potential on Monday, showing the upper-level ridge building over the east coast with surface high pressure to the south of New England:

There are a couple limiting factors that are worth watching that may prevent this heat wave from reaching its full potential. First, dew point values are unlikely to get as high as they have in previous heat waves this summer, when very high humidity came with the heat, boosting feels-like temperatures. Dew points are expected to mix out into the low 60s during max heating, which is a far cry from the 70+° dew points seen in previous heat waves this summer. This will help keep feels-like temperatures close to the actual air temperature.

The other area to watch will be for the potential of low-level onshore flow as the surface high pressure will be just to New England's south and east. This onshore flow would be weak given the overall setup and the fact that it's now August, however, it could be just enough to keep the coastal plain a smidge cooler. If the offshore flow is strong enough, this will not occur, but it will be something to watch. Even with these factors, it will still be in the 90-95° range, so these factors won't prevent the heat wave, but rather take the edge off, a bit.

Below: AIFS showing potential temperatures Tuesday afternoon. You can see subtle cooling right along the coast:

The high pressure near New England during this time will help prevent widespread, organized thunderstorm activity during the afternoons through Tuesday. With that said, a couple rogue storms could fire up at times, mainly over the terrain, as has been the case over the past week. Heading toward the latter part of the week, a cold front will approach and cross New England, bringing the high heat to an end as well as sparking more widespread storms.

This front is currently favored to cross New England later Wednesday into Thursday. This would allow Wednesday to see high heat as well. There's currently a large spread among guidance in regards to exact timing and placement, but a period of increased showers and storms is likely along it. At this point, there's no signal for any widespread, organized rainfall. Temperatures will cool behind the front, but, as of now, it looks like 80s will dominate, so warm weather is expected to stick around.