textproduct: Boston / Norton

WHAT HAS CHANGED

No significant changes to the forecast.

KEY MESSAGES

- Clearing skies and cooler temperatures expected through Sunday morning.

- Potential for a few scattered showers Sunday night, generally south of the Mass Pike. A secondary, sharp temperature drop is then expected for the start of next week followed by a return to dry, fall-like conditions.

DISCUSSION

KEY MESSAGE 1...Clearing skies and cooler temperatures expected through Sunday morning.

A few lingering showers and low clouds this morning through sunrise as the cold front finally pushes offshore. Already seeing clear skies across northern CT and western MA, and expecting those to overspread the rest of southern New England 5-7AM.

Behind the cold front, a rather strong continental high pressure system builds over the Great Lakes and southern Ontario. Northwest winds will advect those cooler temperatures and lower dewpoints into New England, sharply dropping surface temperatures through the weekend. Today's highs are likely to be on the order of 10-15 degrees less than yesterday's, with overnight temps dropping into the low 40s (low 50s on the Cape and Islands).

KEY MESSAGE 2...Potential for a few scattered showers Sunday night, generally south of the Mass Pike. A secondary, sharp temperature drop is then expected for the start of next week followed by a return to dry, fall-like conditions.

The last few model runs have remained consistent in indicating a front lifting north off the DelVarMa coast, bringing potential for more scattered showers to southern New England late Sunday night into Monday morning. Some uncertainty remains in just how far north these showers might reach, but highest potential at this time remains south of the Mass Pike.

A strong high pressure system is then expected to build in right on the heels of a deep Canadian low, bringing a secondary shot of even colder air to New England for the start of next work week. Latest guidance indicates the 540mb line sinking well into New England, possibly as far south as central MA by early Tuesday morning. 850mb temperatures likely drop to near or just below 0C by Tuesday morning. This would support surface highs near 60 degrees with nighttime lows possibly falling into the 30s through Wednesday.

The high then pushes east by Thursday, marking the return of drier conditions, southwest flow, and seasonable temperature to southern New England for the end of the week.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

Forecaster Confidence Levels...

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

12z TAF Update:

Today and Tonight: High confidence.

VFR. N winds around 10 kt gradually decrease to around 5-10 kt by afternoon, with ENE/E winds for the eastern MA coast. SCT mid- level decks possible. N/NNE winds continue overnight.

KBOS Terminal...High confidence in TAF/trends and timing. VFR with NW winds overnight. Winds turn E between 16-17z then ESE 20-21z.

KBDL Terminal...High confidence in TAF.

Outlook /Sunday Night through Wednesday/...

Sunday Night: Mainly VFR, with local IFR possible. Chance SHRA.

Monday: Mainly VFR, with local MVFR possible. Breezy.

Monday Night through Tuesday: VFR. Breezy.

Tuesday Night through Wednesday: VFR.

MARINE

Forecaster Confidence Levels...

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

Through Sunday night...High confidence.

A few showers linger as the cold front continues to push offshore this morning. Winds shift to the NW/N behind the front, and seas subside to less than 4 feet. High pressure briefly returns through Sunday morning with tranquil boating conditions.

Outlook /Sunday Night through Wednesday/...

Sunday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Chance of rain showers.

Monday: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain showers.

Monday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Seas up to 5 ft.

Tuesday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas.

Tuesday Night: Winds less than 25 kt. Seas locally approaching 5 ft.

Wednesday: Winds less than 25 kt.

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...None.