textproduct: Boston / Norton

WHAT HAS CHANGED

No significant changes to the forecast.

KEY MESSAGES

- Breezy and cool conditions expected for Halloween.

- High pressure maintains quiet weather through at least Thursday with warmer than average highs in the 60s.

DISCUSSION

KEY MESSAGE 1...Breezy and cool conditions expected for Halloween.

A cooler day is expected today as the post-frontal air mass moves in. Aloft, 925 mb temperatures cool to around 0C and NW winds continue, yet weaken with high pressure building in. Highs on Halloween will only reach the 50s as a result. Skies clear, and winds falling to or near calm Halloween night will allow for radiational cooling, dropping lows to the 20s and low 30s for much of the region. As is normally the case, the coldest readings will be found across the far interior where lows fall to near 20 degrees.

KEY MESSAGE 2...High pressure maintains quiet weather through at least Thursday with warmer than average highs in the 60s.

High pressure will remain firmly in control of southern New England's weather clear through at least mid to late week as this stretch of pleasant weather continues. A large high moving in from New York will initially move overhead on Sunday, replaced by another dropping south from Canada into Maine mid week. A weak trough will pass over the Canadian maritimes around Tuesday bringing the potential for some showers to northern New England but lack of moisture and dynamics over SNE will keep us dry. The next chance for a pattern change comes around late Thursday/Friday when a mid level trough may dig into the mid-Atlantic, but that is not a certainty at this point. EPS and GEFS ensembles paint a 70-90% chance of PWATS climbing above 1" Thursday-Saturday next week. Run to run variability shows less of a signal for QPF with the latest members showing probs of >0.5" of 24 hr QPF falling from 60-70% for the 12z runs to 30-50%. In the mean time, high pressure maintains a milder than average airmass overhead leading to comfortable highs in the 60s all week. Winds should be light until Friday when our passing low would bring a period of gusty winds.

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. NW winds around 7-14 kt with a few gusts in the lower 20 knot range through lunchtime, with gusts easing in the afternoon. Winds then go light WNW/calm overnight.

Sunday...High confidence.

VFR. WSW winds of 5-10 knots.

KBOS Terminal... High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Sunday Night through Wednesday/...

Sunday Night: VFR.

Monday: VFR. Breezy.

Monday Night through Wednesday: VFR.

MARINE

Forecaster Confidence Levels...

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

Through Saturday Night...High confidence.

SCAs remain in effect through 18z this afternoon given NW winds gusting to 30 kt through tonight and seas to 5 ft into this morning for the outer waters. While winds gradually diminish through the day seas will generally be between 4-5 feet for the outer waters. Heading into this evening and overnight, winds and seas diminish; winds generally fall to 10 kt or less and seas decrease to around 2-3 ft. Tranquil conditions on Sunday with winds falling to 10-15 kt and 2-3 ft seas.

Outlook /Sunday Night through Wednesday/...

Sunday Night: Winds less than 25 kt.

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

Monday Night through Wednesday: Winds less than 25 kt.

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 8 AM EDT this morning for ANZ230>237-251-255-256. Small Craft Advisory until 2 PM EDT this afternoon for ANZ250- 254.