textproduct: Boston / Norton

WHAT HAS CHANGED

No significant changes to the forecast.

KEY MESSAGES

- Mainly dry & seasonable weather continues through mid-week with gradually more sunshine. Lows mainly in the 30s-lower 40s with highs generally well into the 50s.

- Monitoring potential storminess Friday into Saturday, with a still uncertain storm track and storm strength. Mainly plain rain is favored for the lower elevations and coastal plain. Rain possibly changing over to a period of wet snow in the interior higher elevations, although wintry weather impacts seem limited.

- Cloudy, cool, and blustery weather for late weekend into early next week.

DISCUSSION

KEY MESSAGE 1...Mainly dry & seasonable weather continues through mid-week with gradually more sunshine. Lows mainly in the 30s-lower 40s with highs generally well into the 50s.

Low pressure will continue to lift to the north northwest across eastern Canada through the middle of the week. This will result in a persistent westerly flow of air across the region. Outside a brief sprinkle/spot shower or two into early this evening...dry weather will persist. In fact...we do expect to gradually see more diurnal sunshine Tue and especially by Wed as the upper level flow becomes flatter. Highs will be rather seasonable...mainly well into the 50s. Low temps will mainly be in the 30s to the lower 40s. Winds may gust between 15 and 25 mph at times...mainly during the daylight hours.

KEY MESSAGE 2...Monitoring potential storminess Friday into Saturday, with a still uncertain storm track and storm strength. Mainly plain rain is favored for the lower elevations and coastal plain. Rain possibly changing over to a period of wet snow in the interior higher elevations, although wintry weather impacts seem limited.

We continue to monitor developments regarding potential storminess centered around late this week into early in the weekend. The last 24-hours worth of guidance seems to be indicating a primary cyclone transitioning to secondary low pressure development near the northern mid-Atlantic coast Thursday evening; varying storm tracks are still noted across the guidance pertaining to this secondary low, tracking either slowly northeastward near the Southern New England coast Friday and into early Saturday, or passing east well south of Nantucket through the same timeframe. The latter storm track outcome seem to be more favored by the ECMWF and some AI-trained solutions; the operational GFS and Canadian solutions are further northwest/closer to the coast, which would be a stronger, wetter and also colder solution and the system's strength would allow for sub-freezing air aloft to drain southward, supporting a possible transition to wet snow for interior Southern New England.

There still is too much uncertainty across the guidance to really hone into a favored solution, and additional forecast adjustments are likely in the coming days. The lower elevations and coastal plain look to stay as predominantly rain given the influx of milder maritime air. For the hilly terrain in interior Southern New England, latest ensemble snow probabilities show a moderate (20-50%) probability of 1" or more of snow confined to hilly terrain, and low (< 20%) probabilities of snow greater than 4 inches. Those also assume a 10:1 snow to liquid ratio; unless we get really heavy precipitation rates which seems unlikely, those 10:1 SLR accumulations might not be valid given a wetter, gloppy and possibly lower-SLR snow character being more favored. It seems any wintry weather impacts in the terrain would be very limited to nil, and this is reflected by low probabilities of Minor winter storm impacts in the Probabilistic Winter Storm Severity Index graphic.

Stevens Institute guidance also shows a potential 1-1.5 ft storm surge over the eastern coast Friday into Friday night; it seems unlikely we'll see coastal flooding, although Stevens Institute does show minor coastal flooding in Nantucket with water levels around 5.2 ft.

KEY MESSAGE 3...Cloudy, cool, and blustery weather for late weekend into early next week.

We become entrenched in a cool cyclonic flow aloft once the storm system exits offshore by Sunday. This supports a period of cooler, cloudy and blustery weather conditions Sunday into early next week, although dry weather seems favored. Temperatures may trend slightly cooler than normal as we open the early part of next week.

AVIATION /19Z MONDAY THROUGH SATURDAY/

Forecaster Confidence Levels...

Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.

18z TAF Update...

VFR conditions continue through the middle of the week despite some scattered to broken mid level cloudiness at times. A brief sprinkle/spot shower or two remains possible into early this evening...but worst case is very short-lived marginal MVFR conditions. W winds may gust on the order of 15-25 knots at times...mainly during the daylight hours.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF. Outlook /Thursday through Saturday/...

Thursday: Mainly VFR, with local MVFR possible. Breezy. Slight chance RA.

Thursday Night: Mainly VFR, with areas MVFR possible. Windy with areas of gusts up to 30 kt. Chance RA.

Friday: Mainly VFR, with local MVFR possible. Windy with gusts up to 30 kt. RA likely, chance SN.

Friday Night through Saturday: Mainly VFR, with local MVFR possible. Windy with local gusts up to 30 kt. Chance RA, chance SN.

MARINE

Forecaster Confidence Levels...

Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent.

Tonight through Wednesday night...High confidence.

Westerly wind gusts of 20-25 knots will persist at times into early Wed with a second surge late of wind late Tue night behind a cold front. Therefore...we continued small craft headlines for many waters into Tue and even early Wed for our outer-waters before things finally diminish.

Outlook /Thursday through Saturday/...

Thursday: Winds less than 25 kt. Slight chance of rain.

Thursday Night: Strong winds with gusts up to 35 kt. Areas of rough seas. Rain.

Friday: Strong winds with gusts up to 35 kt. Rough seas up to 10 ft. Rain.

Friday Night: Strong winds with gusts up to 35 kt. Rough seas up to 11 ft. Rain likely.

Saturday: Strong winds with gusts up to 30 kt. Rough seas up to 10 ft. Rain likely.

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 7 AM EST Tuesday for ANZ231-251. Small Craft Advisory until 4 PM EST Tuesday for ANZ232>235-237. Small Craft Advisory until 10 AM EST Wednesday for ANZ250- 254>256.