textproduct: Boston / Norton

WHAT HAS CHANGED

Forecast remains on track.

KEY MESSAGES

- Colder today with beneficial rain through the morning, then some drying this afternoon and tonight. Turning milder Friday.

- We'll continue to see large temperature ranges and rain chances through Sunday, but drier and cool next week.

DISCUSSION

KEY MESSAGE 1...Colder today with beneficial rain through the morning, then some drying this afternoon and tonight. Turning milder Friday.

Strong high pressure over the Maritimes will keep the backdoor front south of New England today. Persistent E/NE winds will maintain colder air across region today with little recovery from this morning's low temperatures, only topping out in upper 30s to lower 40s.

Large area of rain moving through southern New England will exit the region later this morning or early afternoon as weak wave of low pressure and its associated weak mid level short wave pass through. Models indicate some drying this afternoon although we may see some spotty lingering drizzle as column remains saturated but any appreciable lift departs offshore. Not looking at any issues with river or stream flooding but rainfall will certainly help with deficits that we've experienced since last fall.

Front will begin to head north again later tonight as low pressure tracks across upper Great Lakes but true milder air doesn't arrive until Friday when we see increasing S/SW winds. Expect to see little change in temperature along with patchy fog and drizzle tonight. We can't rule out some localized pockets of freezing drizzle in the higher elevations of northern MA since temperatures could fall to near freezing, but confidence in its occurrence and resulting impacts is very low. Looks like a dry day Friday with some breaks of sunshine possible, especially across interior southern New England.

KEY MESSAGE 2...We'll continue to see large temperature ranges and rain chances through Sunday, but drier and cool next week.

Expecting to see a brief shot of warm, moist air Saturday allowing for a quick temperature peak in the upper 50s to mid 60s before a trailing cold front sweeps through. As the front stalls later Saturday, it'll bring colder air and another round of rain showers. Expecting overnight temperatures to once again drop into the upper 30s or low 40s. We'll then see a very similar situation on Sunday, with a low tracking across southern Ontario and a one-two punch with a sweeping warm front and trailing cold front. Will see a short- lived surge of warm, moist air with the warm front and another cold airmass moving in not long after as the cold front moves through. Expecting rain showers to move in perhaps a little earlier in the day with the Sunday system compared to Saturday's system, with the heaviest rain more likely in the afternoon/evening.

Heading into next week, we'll see a cooler airmass in place, bringing seasonable or just below seasonable temperatures and a period of drying out.

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...Moderate confidence. Through Friday...

-RA this morning becoming -DZ around mid-morning. Ceilings are lower confidence today as they may bounce between IFR and MVFR through the day. Ceilings become more consistent IFR this evening/tonight with patchy fog developing overnight. LIFR possible. E winds 10-15 kts. Occasional gusts 20-25 kts, mainly for coastal terminals. Up to 30 kts for Cape/Island terminals. Winds decrease around 00Z.

Slow improvement Friday with ceilings improving to VFR by afternoon. SE winds Friday morning shift to the SW by the afternoon.

KBOS Terminal...Moderate confidence in TAF. Uncertainty in the persistence of IFR ceilings today. Ceilings may bounce between IFR and MVFR through the day.

KBDL Terminal...Moderate confidence in TAF. Uncertainty revolves around ceilings as they may bounce between IFR and MVFR through the day.

Outlook /Friday Night through Monday/...

Friday Night: VFR. Breezy.

Saturday: VFR. Breezy. Slight chance SHRA.

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

Sunday: Mainly MVFR, with areas IFR possible. Windy with gusts up to 35 kt. SHRA.

Sunday Night: Breezy. Chance SHRA.

Monday: Breezy.

MARINE

Forecaster Confidence Levels...

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

High confidence through Thu night.

SCAs expanded across all waters except Boston Harbor and Narragansett Bay tonight into Thu for NE gusts to 25 kt. Diminishing E winds Thu night.

Outlook /Friday Night through Monday/...

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

Saturday: Winds less than 25 kt. Areas of seas approaching 5 ft.

Saturday Night: Low risk for Small Craft Advisory winds with local gusts up to 30 kt. Seas up to 5 ft. Slight chance of rain showers.

Sunday: Low risk for gale force winds with gusts up to 40 kt. Rough seas up to 11 ft. Rain showers likely.

Sunday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas. Rain showers likely.

Monday: Winds less than 25 kt. Local rough seas.

BOX WATCHES/WARNINGS/ADVISORIES

CT...None. MA...None. RI...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ231>234-251. Small Craft Advisory until 11 PM EDT this evening for ANZ235- 237. Small Craft Advisory until 6 AM EDT Friday for ANZ250. Small Craft Advisory until 2 AM EDT Friday for ANZ254>256.