Marine Weather and Tide Forecast for North Grosvenor Dale, CT

KEY MESSAGES

- Cool, cloudy, and mainly dry today. Splashover possible for the east coast during the Sunday morning high tide.

- Strong cold front brings a round of widespread showers Sunday, leaves colder temperatures and drier conditions in its wake.

- Cooler than normal Monday. While generally dry weather is expected, a weak area of low pressure could bring clouds and scattered showers.

- Seasonable temperatures Wednesday, though another cold front arrives and temperatures fall once more for the second half of the week.

DISCUSSION
KEY MESSAGE 1...Cool, cloudy, and mainly dry today. Splashover possible for the east coast during the Sunday morning high tide.

Low pressure remains just offshore today, maintaining onshore flow and advecting in marine stratus. This stratus has already started to make its way into southern New England and will continue to do so from east to west through the day today. With persistent cloud cover and NE winds, temperatures today will be cooler, maxing out in the upper 40s and low 50s closer to the eastern coast. The interior can expect only slightly warmer highs compared to the east, reaching the low 60s in the CT Valley and the upper 50s elsewhere. Ridging overhead will help keep the region dry as well.

There is a chance that spots along the eastern coastline could see some splashover or minor coastal flooding during the Sunday morning high tide. High astronomical tides combined with persistent E/NE winds elevate this risk during this period. Will continue to monitor over the next forecast cycle and issue headlines if needed.

KEY MESSAGE 2...Strong cold front brings a round of widespread showers Sunday, leaves colder temperatures and drier conditions in its wake.

An incoming strong cold front Sunday will likely bring a round of widespread showers. This front is part of a potent upper level trough that will be shifting east from the Great Lakes Sunday into Monday. Ahead of this front and trough, PWAT values climb to anomalously higher values around 1.25"-1.30" Sunday morning after dropping mostly 0.5" during the day today. As the front pushes through, the forcing from it interacting with this elevated moisture will lead to widespread showers Sunday. High-res guidance still has hints of MUCAPE around 500 J/kg during the day that could be a factor in some embedded thunderstorms with these showers. Some downpours cannot be ruled out as well, especially in any isolated thunderstorms that may develop. Despite continued rain today, flash flooding is not a big concern. At most, we could expect some poor drainage areas to see some ponding.

Colder and drier air is left in the front's wake, reinforced by breezy W to NW winds starting Sunday afternoon. Gusts to 25 MPH are a possibility post-front. Showers may end with a mix of some snow in the higher elevations of the Berkshires Sunday evening as this colder airmass takes hold, but any accumulations are not expected at this time. Lows Sunday night will likely fall below freezing outside of urban areas, while the cities can expect lows in the mid to upper 30s.

KEY MESSAGE 3...Cooler than normal Monday. While generally dry weather is expected, a weak area of low pressure could bring clouds and scattered showers.

The upper level trough settles overhead Monday, and with it, unseasonably cold air moves in in the midst of CAA. 925 mb temperatures fall below 0C and may even dip to -5C by Monday morning. Breezy W to NW winds continue, and highs may not climb out of the upper 40s and low 50s Monday afternoon. These winds will start to diminish as high pressure approaches from the west, and lows Monday night may fall into the 20s for much of southern New England. Even with approaching high pressure, more guidance has started to latch onto a weak low pressure moving into the region Monday that could bring increased clouds and scattered showers.
Ensemble members (and deterministic models) from different guidance suites have started to indicate some showers Monday as a result of this weak low, though confidence in this feature developing is still relatively low. Outside of this, incoming high pressure should keep the region dry for much of the start of the week before it exits heading into Wednesday.

KEY MESSAGE 4...Seasonable temperatures Wednesday, though another cold front arrives and temperatures fall once more for the second half of the week.

Some showers are a possibility once again heading into Wednesday morning as another shortwave approaches, but more seasonable temperatures make a return as the trough early in the week exits.
925 mb temperatures recover to around 5C with SW flow returning, supporting more seasonable highs in the upper 50s/low 60s. NW flow makes a return towards Thursday/Friday in the wake of another front passing through sometime late Wednesday, and high pressure builds back in as ridging approaches, which should keep the region dry yet chilly.

AVIATION /07Z SATURDAY THROUGH WEDNESDAY/
Forecaster Confidence Levels...

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

06z TAF update:

Through 12z...Moderate to High confidence on stratus timing.

Increasing NE winds draws marine stratus and fog layer westward, appearing to arrive at BOS around 07-08z and continuing to expand westward to BDL through 11-12z. This will bring IFR-LIFR ceilings and visbys in the 1-3 SM range (possibly 1/2SM to 1/4SM at times at BOS and the Cape). Light and variable winds will continue to become NE at 5-10 kt through the early morning hours.

Today...Moderate confidence.

IFR-LIFR ceilings early, with improving visbys in fog. Latest guidance still has some IFR-MVFR optimism around 15-18z, but ceilings then trend downward again as we move into the overnight period. NE winds 6-12 kt, strongest eastern MA.

Tonight...Moderate confidence.

Ceilings deteriorate down to IFR/LIFR levels again tonight. Fog may return as well, bringing visbys down to 2SM and possibly lower. NE winds veer around to SE/S 5-10 kt.

Sunday...Moderate confidence.

Mainly IFR-MVFR with steady rain and mist. Outside chance at a rumble of thunder as strong cold front moves through 18-00z. SW winds around 10 kt, becoming W/NW and increasing to 10-15 kt with gusts 20-25 kt post-frontal passage.

KBOS Terminal...Moderate confidence in TAF. Based on latest satellite imagery, stratus should move in around 08z.
Surrounding terminals already seeing some fog; would expect fog to move in by the time stratus arrives. Fog disperses in the morning, but IFR ceilings generally persist with some guarded optimism on improvement to IFR/MVFR levels. Light winds become NE 5-10 kt. Fog returns heading into tonight.

KBDL Terminal...High confidence in TAF.

Outlook /Sunday Night through Wednesday/...

Sunday Night: VFR. Breezy. Chance RA.

Monday: VFR. Breezy. Slight chance SHRA.

Monday Night through Tuesday: VFR.

Tuesday Night through Wednesday: VFR. Breezy. Slight chance SHRA.

MARINE
Forecaster Confidence Levels...

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

High confidence through the weekend.

Seas 2-4 ft and winds less than 25 kts out of northeast today.
Winds shift SE to S tonight and should remain less than 25 kts.

Passage of stronger cold front Sun may bring SCA conditions to at least outer waters Sun into Mon. Wind gusts may locally approach 25 kt late Sunday in the outer waters. Winds shift NW following this frontal passage.

Outlook /Sunday Night through Wednesday/...

Sunday Night: Winds less than 25 kt. Areas of seas approaching 5 ft. Rain likely.

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

Monday Night through Tuesday: Winds less than 25 kt.

Tuesday Night: Winds less than 25 kt. Seas locally approaching 5 ft. Slight chance of rain showers.

Wednesday: Winds less than 25 kt. Areas of seas approaching 5 ft. Slight chance of rain showers.

BOX WATCHES/WARNINGS/ADVISORIES
CT...None.
MA...None.
RI...None.
MARINE...None.