textproduct: Boston / Norton

WHAT HAS CHANGED

Gale Warnings posted for the eastern coastal waters as well as the MA bays and sounds.

KEY MESSAGES

- Dry weather for most through Saturday with gusty west winds.

- Summer-like Sunday with comfortable humidity and a risk for afternoon showers.

- Chances for a widespread rain Monday into Tuesday. Drier with seasonable temperatures follow for midweek.

DISCUSSION

KEY MESSAGE 1...Dry weather for most through Saturday with gusty west winds.

A low pressure over southeast Canada and a weak high pressure over the central USA will maintain a westerly flow across New England through Saturday. Since we will be closer to the low pressure, expecting gusty winds wind peak speeds up to about 30 mph.

Dry weather persists as well. There is a low chance for a pop-up afternoon shower or two across northern MA Saturday afternoon, but many hours will remain dry even there.

Noticeably lower humidity today that should persist into Saturday. Near to slightly above normal temperatures today, lower slightly for Saturday.

KEY MESSAGE 2...Summer-like Sunday with comfortable humidity and a risk for afternoon showers.

A sheared off mid level shortwave should move through weakly cyclonic flow aloft Sunday. This is not the most potent forcing for showers. However, it does appear to be enough where the idea of typical afternoon popup showers can be dismissed. Thinking the greatest risk will towards northern MA and northern New England due to the closer proximity of the cold pool aloft.

KEY MESSAGE 3...Chances for a widespread rain Monday into Tuesday. Drier with seasonable temperatures follow for midweek.

We continue to track our next chance for a widespread rainfall sometime Monday into Tuesday. There are still significant timing and track differences with this low pressure early next week. The 19/00Z GFS and ECMWF are on the progressive side. So much so, that Tuesday would be dry. The ECMWF was slightly farther west with its track. On the other side of the solution envelope, is the 19/00Z Canadian. While it has a more westward track like the ECMWF, it is slower with its timing. Will continue to take an ensemble approach at this point with the timing. This will focus most of the rainfall from Monday afternoon into Monday night, followed by drying conditions during the day Tuesday.

Still robust signals in the NationalBlend output, with a greater than 80% chance for 24-hour rainfall of 0.50 (12.7 mm) or greater ending 8 AM Tuesday. Even the probability for a 1 inch (25.4 mm) or more is a robust 60-70% during that same time.

Behind this system, high pressure starts to push in from the west, bringing a return to drier weather and seasonable temperatures through the middle of the work week.

AVIATION /06Z FRIDAY THROUGH TUESDAY/

Forecaster Confidence Levels...

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

Today through Saturday...High Confidence.

VFR. Gusty W winds up to 20-30 kt. Winds not as gusty tonight before picking up again Saturday.

KBOS Terminal...High confidence in TAF. KBDL Terminal...High confidence in TAF.

Outlook /Saturday Night through Tuesday/...

Saturday Night: VFR.

Sunday: VFR. Chance SHRA, slight chance TSRA.

Sunday Night: VFR.

Monday: Mainly VFR, with local IFR possible. Breezy. Chance SHRA, chance TSRA.

Monday Night: Mainly MVFR, with local IFR possible. Breezy. SHRA, slight chance TSRA.

Tuesday: VFR. Breezy. Chance SHRA.

MARINE

Forecaster Confidence Levels...

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

Through Saturday: High confidence.

Small Craft Advisories extend into Saturday across the southern outer coastal waters. Lingering rough seas impact the RI sounds into tonight. Small Craft Advisory for the MA southern bays and sounds just for this afternoon due to the gusty winds.

Outlook /Saturday Night through Tuesday/...

Saturday Night: Winds less than 25 kt. Local rough seas.

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

Sunday Night: Winds less than 25 kt.

Monday: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Chance of rain showers. Local visibility 1 to 3 nm.

Monday Night: Strong winds with gusts up to 35 kt. Rough seas up to 10 ft. Rain showers likely, slight chance of thunderstorms.

Tuesday: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Seas up to 5 ft. Chance of rain showers.

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...Small Craft Advisory from noon today to 7 PM EDT this evening for ANZ232>234. Small Craft Advisory until 4 AM EDT Saturday for ANZ235-237. Small Craft Advisory until 4 AM EDT early this morning for ANZ250. Small Craft Advisory until 1 AM EDT Sunday for ANZ254>256.