Heat Cranks Back Up for New England Before Frontal Boundary Sinks South

New England's very nice holiday weekend weather rolls on into Saturday. Temperatures will begin to rise once again, but humidity levels will remain on the lower end of the spectrum. There's really not much at all to say about Saturday, which, in the weather department, is often a very good thing. An area of high pressure will set up to New England's southwest, which is favorable for rising temperatures.

Despite this, warm air advection won't really begin in earnest until overnight tonight and into Sunday, when a weakening warm front approaches the region. With the ridge axis to the southwest of the region, a strong southwesterly flow will develop with the potential for breezy conditions. This breeze will help lift much warmer and more humid air into the region for Sunday. Highs will be in the mid 80s to low 90s for a majority of the region. With dew points well into the 60s, heat index values will shoot well into the 90s for many.

A frontal boundary will be north of New England on Sunday, but slowly sagging southward through the day. This boundary may allow for some scattered thunderstorm development across northernmost New England during the day Sunday, especially across northern Maine. This front will be slowing down as it approaches northern New England, so it won't be a factor for central and southern areas. Any storm that manages to form ahead and along the boundary could contain strong winds.

On Monday, the frontal boundary will likely stall across northernmost New England. This is mainly due to what will be the remnants of Tropical Storm Chantal around the southeast coast line early next week. There's inherent uncertainty with a stalled cold front caused by a tropical system, mainly in how far south the front will sag before stalling. Monday may play out similar to Sunday with scattered storms across the north and continued warm and mainly dry conditions across central and southern New England (some storm activity will be possible across southernmost areas as well).

A more steady and long lasting slug of rainfall may be seen across northern Maine as the frontal boundary sits overhead. With a moisture-rich atmosphere, torrential downpours will be possible with any unsettled weather that develops. A widespread half inch to inch of rain is possible across northern Maine with locally higher amounts should downpours develop. Moisture advecting up the coast may allow for a slight bump in storm/precipitation chances for southernmost New England as well Monday afternoon and evening.

Below: Current precipitation forecast for Monday:

On Tuesday, the frontal boundary will likely begin to push through New England in earnest. This will spread more widespread unsettled weather across the entire region. A period of scattered showers and storms will be likely across most of the region as the front passes. Northernmost New England will likely be the driest as the atmosphere will need some recovery time after the more active Monday. This front will be slow-moving, and the air mass won't be entirely replaced, so it will be warm and remain humid, but not to the levels of Sunday and Monday.

This front will likely remain to the south of New England through the rest of next week. Broad troughing is also likely to remain in place, with multiple waves of energy moving through New England. This will likely bring about plenty of clouds and cooler temperatures.

After Tuesday, it looks Wednesday may be the driest day for New England with a more organized low pressure system moving through in the Thursday to Friday time frame. The upcoming week of weather does line up with our July outlook, which called for bouncing back and forth between bouts of heat and bouts of cooler weather.