Warm Weekend for New England Before Cold Front Sweeps Through

Throughout this past week, this high pressure to the north, along with Erin's persistent onshore wind, has led to cool and sometimes chilly (overnight lows) conditions for mid-August. Both of these features will now be leaving New England as the high pressure breaks down and Erin continues to chug out into the open ocean to weaken and eventually fall apart.

A new area of high pressure will slide into New England for this weekend. This one will be centered more to New England's south, which will promote a more southerly flow, bringing summer temperatures back to the region. A system near Hudson Bay will also allow for return flow from the south, leading to warmer temperatures. High temperatures in the 80s will dominate through the weekend. Saturday will likely see the warmest of the temperatures.

On Sunday, that area of low pressure will continue moving to the northwest of New England. This will be dragging a cold front across the eastern United States over the next few days. Initially, it was looking like this front would cross New England on Sunday, but this front is slow-moving and it may even stall for a time just west of New England. This will make for a dry, nice and quiet day for a majority of New England.

The exception to the dry and quiet day will be across the northern tier of New England. The front will likely interact with a pre-frontal trough during the day, allowing for scattered showers and thunderstorms to develop across western and northernmost areas in the afternoon and evening, possibly extending into the overnight hours as the front moves closer. The pre-frontal trough may allow for a round of scattered morning showers as well, mainly across Vermont.

The main question will be if there will be enough forcing from the front in the afternoon and evening to allow for these storms to develop, since the front will still be well to the west. These storms will be most likely from the mid-afternoon through the evening, but isolated storms may be able to pop up throughout the day in Vermont. There will be ample shear for stronger storms, but very limited instability. The atmosphere won't be overly moisture-rich either. With that said, severe storms aren't likely, but one or two storms could go rogue.

Below: HRRR showing potential weather late Sunday afternoon:

This cold front will likely gradually cross New England through Monday and likely clear the region by Tuesday morning. This will spread the showers and storms across all of New England for Monday. As of now, this will promote a line of scattered showers and storms moving across New England through the day, with the best chance for scattered storms in the areas where the front crosses in the afternoon.

A weak secondary low may form just ahead of the front. Should this occur, a period of more widespread and steady rain could develop rather than just scattered afternoon activity for a portion of the region. That will be the main area to watch with this frontal system. At this point, it appears likely that the secondary system will remain offshore, keeping it's steadier rain offshore. With that said, it may be able to inject some energy and moisture into the cold front, which would allow for more widespread showers.

While this is a possibility, the offshore system and the cold front don't appear to be lined up very well. The system will likely rather quickly pass New England toward Monday morning and the cold front looks to sweep through in the afternoon. This means only a portion of New England may get a beneficial widespread rainfall at some point Monday.

Below: Euro showing potential weather Monday morning (1st image) and Monday afternoon (2nd image). You can see the blob of rain from the system offshore:

As of now, southern and central New England are forecast to see a tenth to a quarter of an inch of rain as they will sit between the trough to the north and the system to the south. This would provide the basis for scattered afternoon storms, but not a more widespread and steady rainfall. The northern tier is poised to pick up a half inch to inch of rain closer to the trough.

Below: Current precipitation forecast through Monday:

At this point, it looks like surface high pressure will once again take control after this frontal passage, leading to another week on the quieter side. Temperatures will likely cool off once again behind the front as the trough may linger aloft. At present, next week doesn't look quite as cool as this past week, but below average temperatures will likely rule.