Another Cool, Damp Weekend is Upon New England

A cold front will be south of New England by Friday morning, bringing slightly cooler temperatures for everyone on Friday. This frontal boundary will really be felt over the weekend as it stalls to the south of New England. A stalled frontal boundary over or near New England will almost always spell cloudy, damp and cool weather, and this weekend is no exception. A weak wave of low pressure will travel across the frontal zone set up between the boundary and an area of high pressure to the north of the region.

It's looking increasingly likely that Saturday will be more on the showery side rather than a washout-type day. Precipitation forecasts now show a mere 0.10-0.25 inches of rainfall for all of New England. The best forcing from the wave of low pressure looks to traverse the region Saturday morning, creating a generally wetter start to the day with a drying trend from north to south in the afternoon.

Below: HRRR showing potential weather Saturday mid-morning (1st image) and Saturday afternoon (2nd image):

Despite the trend toward less rain, a brisk flow off the ocean will continue throughout the day, setting up a typical onshore flow regime. This will keep clouds around with raw temperatures through the afternoon. Occasional drizzle or rain showers will also remain possible in the afternoon, especially near the coast.

The onshore flow and chilly pocket of air in the low levels will create a temperature inversion across the region, with the warmest conditions across the north and gradually cooling moving south, though it won't be particularly warm anywhere in New England this weekend. Highs may struggle to climb out of the upper 50s along the coast.

Below: CMC showing temperature departure from average Saturday afternoon:

A continued onshore flow on Sunday will keep the clouds, isolated showers and cooler temperatures around, especially for southern New England and the entire coastal plain. The frontal boundary will still be to the south of the region with high pressure to the north. With this setup in place, the weather will be warmer and drier the farther north you go in the region as you get away from the influence of both the boundary and the ocean once again.

For temperatures, a gradual warming trend is likely to commence after this weekend. Monday will likely remain cooler, similar to the weekend. The high pressure to the north of New England will eventually slide across New England early next week before moving offshore closer to midweek. This movement of the high pressure offshore will support warm air advection as it helps move mild air up the east coast. With that said, the offshore placement of the high pressure will likely lead to sea breezes, which could delay the arrival of warmer air for the coastal plain.

Overall, confidence in the details of the forecast next week does take a hit as zonal flow continues. This occurs when the jet stream lays flatter across the country, allowing systems to move through quickly. Timing out systems within a fast, zonal flow is a difficult task for current weather models. Weak, quick-moving systems could bring occasional bouts of showers or thunderstorms, but zonal flow doesn't support all-day soaking rain events. There's currently little precipitation in the forecast beyond this weekend. With that said, minor systems may bring a bit of rainfall at a time.

Below: Current 5-day precipitation forecast:

Signals have been consistent in showing a system lifting a warm front across New England late next week. This front would bring about summer heat complete with higher humidity. While timing this out in a zonal flow setup is tricky, later next week has been shown to begin a trend toward more consistent warmth for New England.