textproduct: Boston / Norton

WHAT HAS CHANGED

No significant changes to the forecast.

KEY MESSAGES

- Dry & seasonable weather continues through mid-week with a good amount of sunshine. Temperatures range from the the 30s-lower 40s overnight to upper 50s in the afternoons.

- Monitoring another storm Friday, although there remains high uncertainty in exact timing and storm track.

DISCUSSION

KEY MESSAGE 1...Dry & seasonable weather continues through mid-week with a good amount sunshine. Temperatures range from the the 30s- lower 40s overnight to upper 50s in the afternoons.

Dry westerly flow continues through the middle of the week under zonal flow at the mid levels, sandwiched between a surface low over eastern Canada and high pressure over the southeast U.S. Not much change in the airmass overhead with 925 mb temps in the 6-8C range Tue/Wed. Some lingering moisture in the mid/upper levels moves through early leading to increased cloudcover this morning, but drying out/clearing up by the afternoon with plenty of sun. This continues Wednesday though we'll start to see some moisture/increasing cloudcover filtering in later in the day Wednesday. Altogether, should see high temperatures each day topping out in the mid to upper 50s.

KEY MESSAGE 2...Monitoring another storm Friday, although there remains high uncertainty in exact timing and storm track.

The latest round of ensemble guidance continues to show large uncertainty in the development of a potential storm as we head into the late week/weekend, especially within the track of the low. While all guidance continues to indicate paths anywhere from Maryland to Nova Scotia, the ECMWF and Canadian ensembles (and their AI ensembles) have trended towards the 40N/70W benchmark or slightly south while the GFS ensemble shows tracks closer towards the southern New England coast. Despite the uncertainty in track, most guidance has indicated the low deepening into the mid 990mbs by early Friday morning as well as 850mb temperatures dropping to below freezing across southern New England by Friday evening, supporting chances for some snow to mix into the region Friday and Friday night across the higher elevation regions.

Probabilities continue to indicate only a 30-50% chance for 1"+ of snow in the higher terrain, with the highest chances along the eastern slopes of the Berkshires, and less than 20% probability for 3" or more. As mentioned by previous forecasters, those probabilites assume a 10:1 snow to liquid ratio, and unless we get really heavy precipitation rates (highly unlikely), those 10:1 SLR accumulations would likely be lower with wetter snow characterization being more favored. Any winter weather impacts in the higher elevations are likely to be very limited to nil, and this is reflected by low probabilities of Minor winter storm impacts in the Probabilistic Winter Storm Severity Index.

Heading into the second half the weekend, the low will push further into Atlantic Canada and high pressure begins to build over the Mid- Atlantic region, bringing a return to blustery and dry conditions to southern New England for the start of the next work week.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

Forecaster Confidence Levels...

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

18z TAF Update...

Today and Tonight...High confidence.

Mainly VFR conditions for the rest of today and tonight. Some scattered to broken mid level decks between 030-040 at times this afternoon. W to WNW winds at 8-12 kts. Gusts 18-25 kts at times this afternoon with the higher gusts at ACK. Gusts diminish 20-22Z. Cape/Islands may see gusts linger into the overnight period. There is potential for a brief period with a few gusts up to 18 kts at BOS/ORH between 01-08Z tonight.

Wednesday...High confidence.

VFR conditions. SCT to BKN mid to high level clouds. Winds WNW at 8-10 kts.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Wednesday Night through Sunday/...

Thursday: Mainly VFR, with areas MVFR possible. Breezy. Chance RA.

Thursday Night: Mainly VFR, with areas IFR possible. Windy with local gusts up to 30 kt. RA.

Friday: MVFR/IFR conditions possible. Windy with areas of gusts up to 30 kt. RA likely.

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

Saturday: Mainly VFR, with local MVFR possible. Breezy. Chance RA, chance SN.

Saturday Night: VFR. Breezy. Slight chance RA.

Sunday: VFR. Breezy.

MARINE

Forecaster Confidence Levels...

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

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...have continued a Small Craft Advisory for many waters into Tue and even early Wed for our outer-waters before things finally diminish.

Outlook /Wednesday Night through Sunday/...

Thursday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Seas locally approaching 5 ft. Chance of rain.

Thursday Night: Strong winds with gusts up to 35 kt. Rough seas up to 11 ft. Rain, slight chance of thunderstorms.

Friday: Strong winds with gusts up to 35 kt. Rough seas up to 12 ft. Rain.

Friday Night: Strong winds with gusts up to 35 kt. Rough seas up to 12 ft. Rain likely.

Saturday: Strong winds with local gusts up to 30 kt. Rough seas up to 11 ft. Rain likely.

Saturday Night: Strong winds with gusts up to 30 kt. Rough seas up to 11 ft. Chance of rain.

Sunday: Strong winds with gusts up to 30 kt. Rough seas up to 9 ft. Chance of rain.

BOX WATCHES/WARNINGS/ADVISORIES

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