Very Warm Weather on the way to New England
- Tim Dennis
- 3 days ago
- 4 min read
A ridge of high pressure will set up to New England's south today, allowing for a more southerly flow to begin. With sunshine, this will help boost temperatures a couple notches warmer than Thursday. An approaching warm front will provide the basis for scattered showers and maybe a rumble of thunder across northern New England Friday afternoon and evening. Lesser shower activity will be possible in southern New England in the evening as well.
Below: HRRR showing potential weather this evening:
As the warm front continues to lift northeastward through New England overnight tonight, another round of showers will likely break out in the predawn hours. These scattered showers will continue through the morning hours. The cloudy and showery conditions will likely initially delay the warm-up to start Saturday off.
With that said, these clouds and showers will also significantly limit how cool it gets overnight, with morning lows in the mid-40s north to mid-50s south. This means there will be less ground to make up from the morning to reach very warm afternoon temperatures.
Below: HRRR showing potential weather in the predawn hours Saturday:
Saturday does look primed for warm temperatures. It's always a little difficult to pinpoint exact temperatures in the middle of spring, but multiple factors are lining up to allow for the potential of temperatures well into the 70s and possibly low 80s for southern New England. Very warm temperatures in the mid-levels, a stiff southwest flow to keep the cool ocean air at bay and very limited shower activity will be the main driving forces. The wild card will be the amount of sunshine.
Once New England gets fully within the warm sector, at least partial clearing should occur. The amount of clearing will be what decides whether or not the 70s for northern New England valleys and 80s for southern New England can be achieved. Should clouds be more stubborn, not as much mixing will occur and temperatures will be held in check.
Plenty of sun will allow for deep mixing combined with the strong sun angle this time of year. This kind of setup (a full warm sector in the afternoon hours) supports some clearing of the clouds, but should clouds be stubborn in the afternoon, temperatures will not get to where they're forecast right now. It's always a bit tough to say just how much clouds will break in this setup, sometimes they end up being stubborn and other times they completely clear, allowing bold sunshine (like what happened this past Tuesday for portions of New England).
Below: NAM showing potential cloud cover early Saturday afternoon:
As for the showery side, the afternoon is trending toward mostly dry conditions for all of New England. A few scattered showers will likely be around throughout the afternoon, but most of the region looks dry from about midday to the mid-afternoon hours. From about mid-afternoon through the evening, showers will likely become more numerous as the system's cold front begins to cross. Increased humidity in the warm sector will combine with lift from the front to bring about these showers. It may be able to create a few thunderstorms as well. Thunder will be most likely across western New England.
Below: FV3 showing potential weather Saturday evening:
Another note for Saturday is that winds will be gusty. These gusts will likely peak in the 25-35mph range. Gusts will be out of the southwest, which is helping to get these warm temperatures into here. The southerly nature of the wind will also help keep southern facing coastlines cooler, keeping Rhode Island's coast, Cape Cod & the Islands, Cape Ann and Downeast Maine cooler than the rest.
Below: Euro showing potential wind gusts Saturday afternoon:
The frontal system's cold front will be delayed for a time due to a strong ridge of high pressure offshore. This will also give temperatures time to warm during the day on Saturday. The cold front will pass through later Saturday into Sunday morning, bringing an end to the very warm conditions. High pressure will build to New England's northwest with the low pressure remaining over the Canadian Maritimes. This will bring a breezy and cooler day.
Despite the cold front and cooler weather, it should still get back to around seasonable levels for many on Easter, thanks to the return of more sunshine and a sun angle equivalent to late summer. The high pressure to the northwest may bring a glancing shot of polar air to the northern tier, allowing for a generally cooler day (relative to average) than central and southern New England.
Below: AIFS showing temperature departure from average Sunday afternoon:
As for Marathon Monday, the timing on a frontal system has been trending toward a later arrival Monday into Tuesday. New England looks to squeeze into a ridge between a departing low pressure and incoming frontal system. This lends itself to a dry and quiet day with seasonable temperatures. It will likely be chilly in the morning with afternoon highs in the low 60s inland. The high pressure will allow for an afternoon sea breeze to develop, leading to a light head wind and cooler temperatures in Boston.
Below: Current weather map for Monday, April 21:
Looking at the bigger picture, the United States will be moving away from a ridge-in-the-west-trough-in-the-east setup, as mentioned in the beginning. This will be trending toward a more zonal flow entering into next week (which is when the jet stream lays flatter across the US without pronounced ridges or troughs).
With that said, recent guidance does show weak ridging in the east and weak troughing in the west. This kind of setup is favorable for milder air spreading across the United States, allowing for generally seasonable to mild conditions to spread across much of the country, as seen in the Climate Prediction Center's 6-10 day outlook below.
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