textproduct: Boston / Norton

WHAT HAS CHANGED

No significant changes to the forecast at this time. Latest trends remain on track.

KEY MESSAGES

- Dry and seasonable today through much of the day Thursday.

- Risk for scattered showers and a few thunderstorms returns Thursday evening/night into Friday.

- Showers may linger into Saturday. Otherwise, dry weather expected through much of the weekend into the start of next week.

DISCUSSION

KEY MESSAGE 1...Dry and seasonable today through much of the day Thursday.

Rain has continued to pull further offshore of the Cape and Islands early this morning and will continue to do so as we approach sunrise. Patchy fog this morning enhanced by the recent rainfall will also burn off as winds pick back up and the sun rises. With the wave responsible for this rain continuing offshore and more westerly winds picking up, expect a sunnier, drier day across southern New England today with highs in the low 80s and upper 70s. This drier pattern will last into much of tomorrow as well as high pressure over much of the eastern US stretched up into the northeast.

KEY MESSAGE 2...Risk for scattered showers and a few thunderstorms returns Thursday evening/night into Friday. Monitoring for severe risk Friday night.

Our next chance for rain and some thunderstorms returns Thursday night as another shortwave approaches and crosses into southern New England. With the main surface low shifting eastward over the Great Lakes into southern Ontario, its warm front extends out to its east and will likely track into the region Thursday night. For much of these showers, embedded thunder out in western MA is a possibility, but the risk goes down considerably east of Worcester. The risk for severe storms developing is low in the morning, though later in the afternoon/evening it increases ahead of the low's cold front behind the morning's warm front. Ensemble guidance varies greatly still on how much instability may be present Friday evening ahead of the second round of storms, but some models are hinting at stronger effective shear being present. The forcing from the arriving front will likely be enough to generate this second round of showers with some storms possible, but whether these may turn severe is still uncertain at this time given the lack of a consensus on how much instability may be present at the same time as these other two ingredients. Will continue to monitor as we get closer to this timeframe.

KEY MESSAGE 3...Showers may linger into Saturday. Otherwise, dry weather expected through much of the weekend into the start of next week.

Heading into Saturday morning, there may be some lingering showers around. Another wave of low pressure looks to track to our south based on the latest guidance, though the chance remains that some showers could impact the south coast heading into the daylight hours. Aside from this, dry weather is expected to return heading into the start of next week as high pressure associated with an amplified upper level ridge moves into southern New England. A warming trend also kicks off for the start of the work week, continuing into midweek. However, details on just how warm it may get are still uncertain at this time.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

Forecaster Confidence Levels...

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

12z TAF Update...

Today through Thursday...High confidence.

VFR conditions today through Thursday once any lingering fog patches and MVFR cigs towards the Cape/Islands dissipate by mid-morning. NW winds should gust to between 15 and 20 knots this afternoon. Light/calm W winds tonight becoming SW 10 knots or less on Thursday...But localized sea breezes may develop across portions of the immediate coast.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Thursday Night through Sunday/...

Thursday Night: Mainly VFR, with local MVFR possible. Chance SHRA, isolated TSRA.

Friday: Mainly VFR, with local MVFR possible. Breezy. Chance SHRA.

Friday Night through Saturday: VFR. Chance SHRA.

Saturday Night through Sunday: VFR.

MARINE

Forecaster Confidence Levels...

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

Through Thursday...High confidence.

Winds are generally light through Thursday, varying in direction while keeping a westerly component. Sustained speeds and gusts less than 20 kt through tomorrow (outside of a brief period of 20 kt gusts possible this afternoon over Nantucket Sound) with seas 2-4 feet. Areas of the southern outer waters could see seas to 5 ft tonight, but these are not expected to be widespread or prolonged.

Outlook /Thursday Night through Sunday/...

Thursday Night through Saturday: Winds less than 25 kt. Chance of rain showers.

Saturday Night: Winds less than 25 kt. Slight chance of rain showers.

Sunday: Winds less than 25 kt.

BOX WATCHES/WARNINGS/ADVISORIES

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