More storm chances for New England today and tomorrow

Today will see a frontal boundary slowly sag through New England. Another boundary will be set up to the north of New England. This will allow for another round of thunderstorms throughout the day. Storms will likely be more widespread across New England today than the previous couple days.

Photo byNew England Storm Center

After a morning round of showers and storms across the northern tier of New England, additional scattered storms will likely be around throughout the afternoon and evening. A line of storms is looking to develop along the southern frontal boundary beginning early this afternoon. This line will push east-southeastward through the afternoon and into the evening.

Afternoon storms will be most likely across central and southern New England, where the morning shield of rain remained away from, but there is still a chance of spotty storms redeveloping across the northern third of the region.

HRRR showing potential weather early this afternoon (1st image) and heading toward late afternoon (2nd image):

Photo byHRRR/Tropical Tidbits

Photo byHRRR/Tropical Tidbits

There will be a chance for some strong to severe storms, although a severe weather outbreak is unlikely. More storms will likely remain sub-severe than ones that strengthen to those levels. The greatest threat with severe storms will be strong wind gusts. Spotty large hail is also possible, mainly in northern New England.

Photo byNew England Storm Center

As for the ingredients for severe weather, there will be a strong forcing mechanism with the frontal boundary and disturbance moving through New England. Moisture is abundant, as evidenced by the very high humidity levels. Shear is modest, but instability will be a limiting factor. CAPE values will build into the 1,000-1,500 range, but lapse rates will not be favorable. Morning clouds and showers may also limit the amount of energy, especially early in the afternoon. All of this combined to bring some strong storms, but not an outbreak.

With a moisture-rich atmosphere in place, storms will also be capable of producing torrential downpours. Rainfall rates could approach 2" an hour at times (it wouldn't rain at that rate for anywhere near an hour straight, however). This could result in some localized, minor flooding.

The afternoon/evening line of storms should wind down shortly after sunset as it approaches the south coast. Across northern New England, more scattered storms may fire in the evening and continue into the first part of the night as forcing from the disturbance will still be present along with some instability. Whether or not this happens will come down to how the daytime activity pans out. These storms would be weakening and likely begin to fall apart heading toward the overnight hours.

HRRR showing potential weather this evening:

Photo byHRRR/Tropical Tidbits

On Monday, another disturbance will form along the stalled cold front to the north of New England. This will send the cold front through New England during the day Monday. This frontal passage will provide yet another opportunity for a round of thunderstorms across New England for Monday afternoon.

Photo byNew England Storm Center

The ingredients for severe storms will be generally stronger than Sunday. The timing of the cold front will determine where storms are strongest and most widespread. As of now, this threat looks highest across central New England (southern VT, NH; northern MA). This is where the front looks to cross closer to peak daytime heating. This is also where the ingredients for stronger storms will be most present. There are still questions as to the overall coverage of storms.

Photo byNew England Storm Center

Farther north in New England, the cold front will cross before peak heating while the southern third of New England will be further removed from the forcing of the low pressure system. The timing appears to be later than Sunday with storms not arriving in southern New England until the evening. The primary threats will be strong winds, but freezing levels are looking to fall from over 14,000 feet on Sunday to around 13,000 feet for Monday. This could introduce more of a hail threat as opposed to Sunday.

After Monday, the cold front will likely stall just to the south of New England, keeping mainly cloudy and cool conditions around for much of the week. Heading toward the end of the week, what's left of Tropical Storm Debby may move up the east coast and interact with the stalled front near New England. There is plenty of disagreement in the evolution of this, and it won't start to become clear until the storm has passed through Florida.

Photo byNational Hurricane Center

While much needs to be sorted out, a post-tropical system interacting with a stalled cold front is a recipe for a period of downpours for New England. The key to the end of this week's forecast will be the level of interaction between the system and the cold front. This remains just something to keep in the back of the mind for now.