textproduct: Boston / Norton

WHAT HAS CHANGED

No major changes since the last forecast. Guidance continues to indicate seasonably mild temperatures through Saturday, then turning cold again on Sunday. Unsettled weather remains possible next week.

KEY MESSAGES

- Seasonable today and Friday, then warm Saturday.

- Cold front may bring snow showers Sunday morning, then Arctic outbreak brings well below normal temperatures to start the week

- Unsettled weather remains possible next week, but uncertainty remains high.

DISCUSSION

Key Message 1...Seasonable today and Friday, then warm Saturday.

The region remains under a weak troughing pattern through the rest of the week, keeping it in near-normal high temperatures in the upper 30s to low 40s during the day, but still chilly at night, with lows tonight dipping into the teens and low single digits, aided by good radiational cooling. Skies today start mainly sunny but turn mostly cloudy as a low-pressure system passes well offshore. Guidance continues to keep precipitation well offshore with a low chance for snow showers over Nantucket. Building an upper-level ridge will bring sunny skies Friday and Saturday, with warmer-than- normal temps in the mid to upper 40s expected on Saturday.

Key Message 2...Cold front may bring snow showers Sunday morning, then Arctic outbreak brings well below normal temperatures to start the week

Stronger shortwave trough passes to the North across Northern New England late Saturday into Sunday, sending a Cold front down into the region early Sunday. Moisture will be rather limited with this cold front, but there may be enough forcing to squeeze out a few snow showers Sunday morning. High temperatures behind the cold front on Sunday only reach the low to mid-30s. An Arctic airmass then enters the region from Sunday night through Monday night. Low temperatures on Sunday and Monday morning will be in or near the single digits, with Mondays highs in the low to mid 20s. Winds will be rather calm during this arctic outbreak, keeping the wind chill index from dropping below zero.

Key Message 3...Unsettled weather remains possible next week, but uncertainty remains high.

Temperatures are expected to warm back to more seasonal levels Tuesday through the rest of next week, with highs in the upper 30s to low 40s. As for the precipitation outlook into next week, guidance has yet to lock on to a consistent solution; however, a shortwave may drop down from northern New England on Monday with another shortwave exiting the Great Lakes sometime midweek. This could lead to more unsettled weather, but uncertainty remains high.

AVIATION /12Z THURSDAY THROUGH MONDAY/

Forecaster Confidence Levels...

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

12z TAF Update...

Today: High Confidence

VFR after fog burns off between 13-14z. Light west winds today at 5-10 knots

Tonight: High Confidence

VFR with brief period of MVFR possible on the Cape and Islands. Winds turn NW under 5 knots.

Tomorrow: High confidence

VFR. Light SW winds under 10 knots.

KBOS Terminal...High confidence

VFR with light westerly winds around 10 knots today

KBDL Terminal...High confidence

VFR with light northerly winds turning southerly later this morning.

Outlook /Friday Night through Monday/...

Friday Night through Saturday: VFR. Breezy.

Saturday Night: VFR. Slight chance SN.

Sunday: Mainly VFR, with local MVFR possible. Breezy. Chance SN.

Sunday Night: VFR. Breezy.

Monday: VFR. Slight chance SN.

MARINE

Forecaster Confidence Levels...

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

Today through Friday Morning...High confidence.

Southwesterly winds 20-25 knots diminish across the southern waters but remain across the northern waters into the morning hours. Seas 5-7 feet linger across the southern outer waters through Friday so SCA headlines will remain. Nonetheless...lingering swell across our southern waters will only slowly diminish so small craft headlines will need to continue well into Thu.

Outlook /Friday Night through Monday/...

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

Saturday through Saturday Night: Winds less than 25 kt.

Sunday: Winds less than 25 kt. Slight chance of snow.

Sunday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of seas approaching 5 ft. Chance of freezing spray.

Monday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of snow.

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 7 PM EST this evening for ANZ235- 237. Small Craft Advisory until 11 AM EST this morning for ANZ250. Small Craft Advisory until 8 PM EST Friday for ANZ254>256.