Scattered Storms Kick off Fourth of July Weekend in New England

Today will see a rather sharp trough pass to the north of New England, with a surface cold front moving across the region later in the day. This will likely provide the basis for another round of scattered showers and thunderstorms, especially later in the day. The front looks to cross New England through the afternoon hours, which will provide the basis for some storms to become stronger across southern and central New England.

The cold front will likely cross northern New England in the late morning through mid-afternoon while it crosses southern New England through the evening. Storms will be most numerous while the front crosses, but an uncapped atmosphere will likely allow scattered storms to develop well ahead of the front as well. The main time frame for storms will be 12pm to 5pm for northernmost New England and 2pm to 7pm for the rest of the region.

Below: Potential weather around mid-afternoon today (1st image) and this evening (2nd image):

All of interior New England will have a chance to see a strong to severe storm this afternoon or evening. Storms will likely be organized into clusters and lines as the cold front moves through, though individual supercells will be possible ahead of the frontal boundary as efficient daytime heating and an uncapped atmosphere will allow for storm development ahead of the boundary.

Looking at the main ingredients for severe storms, they are split between being ample and being marginal. Deep shear up to 35-40 knots will be in place, which is enough to allow for strengthening storms. Lift will be provided by the cold front and the potential for a pre-frontal trough.

Moisture and instability will be more on the marginal side. With a mainly westerly flow in place, dew points will run in the upper 50s to low 60s and Precipitable water values will be just over an inch. This is enough to allow for storms, but it's certainly not jumping off the page. While an uncapped atmosphere will allow for maximum heating today, instability will likely be more marginal as well, with CAPE values climbing to the 1,000-1,500 range.

With that said, a full-scale severe weather outbreak is not expected. Storms will likely remain scattered in nature, so not everyone will get a storm, never mind a severe storm. Damaging winds will be the greatest threat within stronger storms. Large hail will also be possible given the cold pool aloft and deep shear. Without deep moisture in place, the threat of torrential rainfall and flash flooding will be lower.

The trough passing to the north of New England will lift northeast of Maine on the Fourth of July. This will set up very nice (near perfect, actually) weather for the holiday. Warm temperatures, low humidity and mainly dry conditions are expected. The trough could send some isolated, brief showers into Maine during the afternoon. Humidity levels will stay on the lower end Saturday before a stronger southwest flow kicks back in around a ridge of high pressure to our southwest and ahead of an incoming trough.

This will also pump temperatures back up starting on Sunday. Sunday and Monday will likely see widespread highs well in the 80s to mid 90s. A trough/cold front will push through the region Monday into Tuesday of next week, bringing another round of unsettled weather and cooler temperatures heading toward the middle of next week.