Marine Weather and Tide Forecast for West Falmouth, MA

NEAR TERM /THROUGH TONIGHT/
Key Messages:

* Turning very cold overnight, with areas dropping below zero in the far north/northwest areas of Massachusetts.

No significant weather concerns for the rest of today and tonight as an area of high-pressure settles overhead; which originated near the Arctic Circle. Periodic wind gusts this afternoon will diminish with a light to calm wind overnight. Clear sky in conjunction with light winds leads to radiational cooling. Temperatures at 500mb are -32C to -30C, which is anomolously cold; 10th percentile of climatology for today's date per Chatham sounding climatology. Expecting frigid temperatures, coldest across northern and western Massachusetts where snow depth ranges between 4 and 8 inches, here the overnight temperatures lower between low single digits to a few degrees below zero. Elsewhere, temperatures are in the single digits and teens near the coast.

SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/
Key Messages:

* Dry conditions through the daylight hours of Tuesday, then a quick hitting system brings snow/rain showers overnight to the region.

* Minor snow accumulations are possible, but not expected to be widespread.

Quiet and dry weather throughout the daylight hours Tuesday, with the most active period overnight into Wednesday morning. During the daytime an area of high-pressure moves east of New England, clear skies gives way to increasing cloud cover during the afternoon as WAA bring elevated PWATs into the region. Overall, chilly day as 925mb temperatures are -8C to -6C and with a mixed boundary layer, afternoon high temperatures are once again in the 20s to mid-30s at the coast.

Tuesday night, mid-level warm front and 850mb frontogenesis, between 00z-06z, provides a brief hit of snow showers. The layer doesn't appear super saturated, thus not anticipating significant snowfall.
High-res models picked up on this, indicating brief round of snow showers and coastal rain showers, from 7pm and 1am. Antecedent temperatures may allow for minor accumulations on paved surfaces of a few tenths of an inch. But, the higher end amounts of up to an inch remains possible, though not expected to be widespread.

Any wet and untreated surfaces could become slick as the overnight temperatures are below freezing between the upper teens through the 20s.

LONG TERM /WEDNESDAY THROUGH SUNDAY/
Key Messages:

* Periodic chances for precipitation through Sunday.

* Uncertainty in pattern details (timing, amounts, precip type), especially Wednesday onward.

Rather good overall agreement with the synoptic pattern amongst the latest guidance suite members. Timing and amplitude differences continue to grow into this weekend. The overall pattern suggests a deepening mid level trough over the eastern USA for the second half of this upcoming week. The largest detail differences involve the evolution of a mid level cutoff somewhere between Hudson Bay and Quebec. Our proximity to this particular feature will play a role in how much lift can be used to generate cold advection showers across our region. The guidance also suggesting a prominent mid level storm track to our south late this week into early next week. Some guidance suggested the possibility of a fast-moving low pressure zipping by this weekend, which would enhance precipitation chances.
Still have some doubts how close this low pressure can actually get to our region.

Have the greatest confidence for snow across the higher terrain of southern New England Wednesday, with a snow-to-rain transition at the lower elevations. Once this low pressure to our north and west passes by, the mode of precipitation is expected to transition to more of a cold advection showery pattern Thursday into Saturday.
While the possibility of a passing shower cannot be completely dismissed, there should be many dry hours during this time, especially Thursday and Friday. Will need more time to figure out the precise track of a possible low pressure Saturday into Sunday.
Should it pass close enough to our region, we would see a greater risk for a more widespread light snow at night, and more light rain mixing in during the daytime. Not looking like a blockbuster storm at this point, should it even materialize at all. A high pressure should take over once more early next week.

Temperatures are anticipated to be below normal late this week into early next week.

AVIATION /19Z MONDAY THROUGH SATURDAY/
Forecaster Confidence Levels...

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

18Z TAF Update:

Today through Tuesday... High Confidence.

Dry and VFR, occasionally lower end VFR ceilings across terminals in eastern Massachusetts through sunset. Gusty NW to NNW winds, gusting between 20-25 knots, then diminishing after 21z. Light northerly wind tonight becoming calm. Wind direction on Tuesday starts out of the west less than 5 knots, becoming south-southwest 8-12 knots after 15z.

Tuesday Night... Moderate Confidence.

VFR, lowering to MVFR/IFR, isolated to scattered snow and/or rain showers possible after 00z through 06z, with minor accumulation on runways less than an inch. Wind from the southwest are gusting up to 15 knots over land and 25-30 knots over the coastal terminals.

KBOS Terminal...High Confidence in TAF.

KBDL Terminal...High Confidence in TAF.

Outlook /Wednesday through Friday/...

Tuesday Night: Mainly VFR, with areas MVFR possible. Windy with gusts up to 35 kt. Chance SN.

Wednesday: Mainly VFR, with local IFR possible. Windy with local gusts up to 30 kt. Chance RA, chance SN.

Wednesday Night: Mainly VFR, with local IFR possible. Windy with local gusts up to 30 kt. Chance RA, chance FZRA.

Thursday through Thursday Night: VFR. Breezy.

Friday: VFR. Breezy. Slight chance SN.

MARINE
Forecaster Confidence Levels...

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

Today through Tuesday Night... High confidence.

As high pressure builds in from the west, gusts diminish, falling below advisory criteria this afternoon. Residual sea state with seas 4 to 6 feet remain through the first half of the overnight. Shifting wind direction Tuesday, becoming southwest with gusts 15-20 knots by late morning, 30+ knots Tuesday night, as a fast moving system brings near Gale Force conditions into Wednesday. Seas are building Tuesday night, 5-8 feet across southern waters, and 4-6 feet for the eastern waters.

Outlook /Wednesday through Friday/...

Tuesday Night: Low risk for gale force winds with gusts up to 35 kt. Local rough seas. Chance of rain.

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

Wednesday Night: Strong winds with gusts up to 35 kt. Areas of rough seas. Chance of rain.

Thursday: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Slight chance of rain.

Thursday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Areas of rough seas. Slight chance of snow.

Friday: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Slight chance of rain, slight chance of snow.

BOX WATCHES/WARNINGS/ADVISORIES
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 6 PM EST this evening for ANZ231- 235-237-251.
Small Craft Advisory until 4 AM EST Tuesday for ANZ250-254>256.