textproduct: Boston / Norton

WHAT HAS CHANGED

No significant changes to the forecast.

KEY MESSAGES

- Wet and unsettled weather returns today into this weekend. Continued above normal temperatures before cooler conditions arrive Sunday and beyond. Dry weather expected most of next week.

DISCUSSION

KEY MESSAGE 1...Wet and unsettled weather returns today into this weekend. Continued above normal temperatures before cooler conditions arrive Sunday and beyond. Dry weather expected most of next week.

High pressure well southeast of New England will maintain southerly winds into tonight. A slow-moving cold front approaches from the west today, then stalls across our region Friday while waves of low pressure travel along it. A final low pressure is expected to move into the Maritimes Sunday, finally moving this front offshore.

The greatest rainfall chances will be across western MA today. The focus then shifts across RI and southeast MA tonight into Saturday. Relatively light rainfall anticipated today and tonight. The same cannot be said for Friday into Saturday morning. The prolonged nature of this rainfall, as well as the well above normal amounts of moisture, should lead to a significant rainfall. The latest guidance increased potential rainfall amounts yet again. However, there is only moderate confidence in the location of the axis of heaviest rainfall. Variance in rainfall 48-hour amounts in the ensembles were between 0.75-1.75". This is a signal that not all the details are refined quite yet. Further changes are possible with later forecasts.

All that said, our best estimate is for 0.50-1.00" of rainfall across the western half of southern New England through Saturday. Farther east, rainfall of 1.00-2.00" is more likely. A narrow band of rainfall up to 3" is possible. Again, the exact locations this sets up is not yet known, but the most likely area for be from southern RI into southeast MA.

Fortunately, we've been very dry for a while and flash flood guidance is high. Still not expecting flash flooding to be an issue. Some poor drainage/urban flooding is possible, especially given the possibility of leaves blocking drainage this time of year. There continues to be a marginal risk within the Excessive Rainfall Outlook for Friday into Saturday.

Rain chances drop off Saturday morning but showers will continue to be possible through Sunday morning with a cyclonic flow overhead; nothing like Friday/Friday night though. NW flow ushers in a colder, albeit closer to normal, airmass for early next week with high temperatures returning to the 50s.

A series of fronts then move across southern New England next week. However, limited moisture should only mean periods of clouds at times and mainly dry weather.

AVIATION /06Z THURSDAY THROUGH MONDAY/

Forecaster Confidence Levels...

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

Today...Moderate confidence.

Areas of MVFR and IFR to start towards the south coast. Slow improvement to VFR from SE to NW this morning. Some areas may return to MVFR in the later afternoon hours towards western MA.

Tonight and Friday...Moderate confidence.

MVFR to IFR. Areas of LIFR possible towards the early morning hours Friday. Rain moves in from W to E overnight, settling entirely over the region by Friday morning. Embedded TS possible towards the Cape, Islands, and south coast early Fri morning. Winds generally S to SSW, becoming light over much of the interior. Winds generally up to/around 10 kt towards the Cape and Islands, with gusts to 20 kt possible.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Friday Night through Monday/...

Friday Night: MVFR/IFR conditions possible. Chance RA, patchy BR.

Saturday: Mainly VFR, with local IFR possible. Chance RA.

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

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

Sunday Night through Monday: VFR. Breezy.

MARINE

Forecaster Confidence Levels...

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

Through Friday...High confidence.

Surface high pressure stays positioned SE of the waters into Friday. A cold front approaches the waters tonight, then stalls nearby Friday. Marginal Small Craft Advisory conditions are possible across the southern coastal waters late tonight into Friday. Confidence is not yet high enough to issue such an advisory at this time. This will need to be monitored with later forecasts.

Outlook /Friday Night through Monday/...

Friday Night: Winds less than 25 kt. Seas up to 5 ft. Rain, patchy fog. Local visibility 1 to 3 nm.

Saturday: Winds less than 25 kt. Seas up to 5 ft. Chance of rain, patchy fog.

Saturday Night: Low risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Chance of rain.

Sunday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 10 ft. Slight chance of rain.

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

Monday: Strong winds with gusts up to 30 kt. Rough seas up to 8 ft. Slight chance of rain.

CLIMATE

Persistent unseasonable warmth over the next couple of days will challenge calendar-day record highs and record high minimums across southern New England climate sites.

Daily Record Highs to Watch:

Boston (BOS): Wednesday 78F (1987)|Thursday 79F (1994)

Hartford/Bradley (BDL): Wednesday 78F (1987)|Thursday 75F (2022)

Providence (PVD): Wednesday 77F (1987)|Thursday 75F (1994)

Worcester (ORH): Wednesday 74F (1987)|Thursday 73F (1994)

Daily Record Lows to Watch:

Boston (BOS): Thursday 56F (1994)|Friday 57F (2020)

Hartford/Bradley (BDL): Thursday 55F (1994)|Friday 56F (2020)

Providence (PVD): Thursday 56F (1994)|Friday 58F (2020)

Worcester (ORH): Thursday 55F (1994)| 55F (2020)

BOX WATCHES/WARNINGS/ADVISORIES

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