Nantucket Sound Marine Forecast
|Overnight...N Winds 20 To 25 Kt, Increasing To 25 To 30 Kt. Seas 4 To 6 Ft.|
|Tue...N Winds 20 To 25 Kt, Becoming Ne 5 To 10 Kt In The Afternoon. Seas 4 To 6 Ft.|
|Tue Night...S Winds 5 To 10 Kt, Becoming Sw 10 To 15 Kt With Gusts Up To 20 Kt After Midnight. Seas 2 To 4 Ft. A Chance Of Rain.|
|Wed...W Winds 10 To 15 Kt. Gusts Up To 20 Kt In The Morning. Seas 2 To 4 Ft.|
|Wed Night...Nw Winds 5 To 10 Kt. Seas 2 To 3 Ft.|
|Thu...Sw Winds Around 5 Kt, Becoming S 10 To 15 Kt In The Afternoon. Seas Around 2 Ft. A Chance Of Rain.|
|Thu Night...S Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 2 To 4 Ft. Patchy Fog. Rain.|
|Fri...Sw Winds 15 To 20 Kt With Gusts Up To 25 Kt. Seas 2 To 4 Ft. A Chance Of Rain.|
|Fri Night...Sw Winds 10 To 15 Kt With Gusts Up To 25 Kt. Seas 2 To 3 Ft. Patchy Fog. Rain Likely.|
|Sat...W Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 2 To 4 Ft. A Chance Of Rain.|
|Sat Night...Nw Winds Around 20 Kt With Gusts Up To 30 Kt. Seas 3 To 5 Ft. Seas Are Reported As Significant Wave Height, Which Is The Average Of The Highest Third Of The Waves. Individual Wave Heights May Be More Than Twice The Significant Wave Height.|
| Area Forecast Discussion|
National Weather Service Boston/Norton MA
933pm EST Monday Feb 6 2023
High pressure builds in from the west late tonight and Tuesday with colder conditions. Scattered rain/snow showers Tuesday night with a frontal system, then turning milder again through the end of the week with temperatures well above normal, especially Friday. Another frontal system will bring rain Thursday into Thursday night followed by drier and unseasonably mild weather Friday. Temperatures trend cooler along with unsettled conditions into the weekend.
Near Term - Until 6am Tuesday Morning
Both sky cover and winds have diminished more quickly than forecast as low pressure pulls to our north and east. Some lower clouds hang on across the Cape and Islands given their proximity to the low compared to the rest of the region. Minor adjustments were made to the timing of the forecast, but overall, the forecast remains in good shape.
Given that winds have diminished rather quickly this evening, many of our Gale Warnings were converted to Small Craft advisories. The remaining Gales will be converted as they expire.
Update 650 PM:
Clouds continue to shift east and away from southern New England as a powerful surface low moves NE towards Nova Scotia. Gusts continue to come in from the N/NE generally around 30 to 40 mph along the coast. As the low shifts away, winds will begin to ease. No significant changes were made as the forecast continues to remain on track. Only made small changes to bring the forecast in line with the latest observations.
Previous discussion below.
A deep low pressure system off the southeast coast of southern New England continues east over The Atlantic maritimes overnight. As this system pulls away the pressure gradient driving gusty north/northeast wind gusts this evening will weaken substantially. This will eventually lead to the gusty north/northeast winds diminishing overnight. A drier air mass filters in from the west and results in skies clearing across most of interior southern New England. Clouds may linger over the coastal areas. As the atmosphere decouples after midnight we should see fairly efficient radiational cooling that will support chilly overnight lows in the upper teens to low 20s across the north and western areas. Along the coastal plain, some cloud cover and boundary layer mixing will support more mild overnight low temperatures ranging from the mid 20s to the low 30s over The Cape and Islands.
Short Term - 6am Tuesday Morning Through Tuesday Night
Northeast winds continue for the first half of the day tomorrow. This will support cooler temperatures during the afternoon with highs struggling to escape the 30s. As high pressure shifts east of the region during the mid-afternoon hours, southerly flow will take over and support increasing cloud cover ahead of an approaching cold front.
An upper-level short-wave trough propagates over southern New England tomorrow night. This will drag a surface cold front through the region with a period of scattered showers. The PType associated with these showers remains a forecast challenge, but as of now model soundings suggest a period of snow will be likely for most of the locations that experience precipitation after 7 pm. The high terrain of The Berkshires/Worcester hills will be the areas where wintry precipitation will be most likely, while the lower elevations/coastal plain are more likely to see rain. Also can't rule the possibility of periods of freezing rain/sleet as model soundings reveal a shallow melting layer as this front rolls through the region. Any snow/ice accumulations will be limited to dusting/trace amounts, therefore impacts from any wintry precipitation will be little to none. Expect these showers to be clear of the region by day break on Wednesday.
Long Term - Wednesday Through Monday
Highlights... * Warming trend Wednesday into Friday, near record high temperatures possible on Friday, then trending cooler for the weekend.
* Unsettled pattern Thursday into Friday and then possibly into this upcoming weekend.
Ready or not, another mild stretch of weather is around the corner starting Wednesday. Looking at the mid-level, heigheights are increasing Wednesday, transitioning towards an amplified mid-level ridge Thursday and Friday. Much of the deterministic and ensemble guidance continues to support well above normal temperatures Wednesday, Thursday, and Friday... especially Friday. Mid to upper 40s would be pretty common Wednesday and Thursday, with lower 40s in the higher terrain. As for Friday, 850mb temperatures over southern New England range from +7C to +10C! May not sound impressive, but that is a +12C to +16C departure from normal. Friday appears to be the warmest day of this week with highs potentially in the middle and upper 50s. These temperatures could be under done by a few degrees if we breakout into more sunshine.
That said, afternoon high temperatures will be close to the daily record high for Friday. Record high for Boston is 60F set in 1990, Worcester is 55F set in 1909, Providence is 58F set in 1909, and Hartford is 55F set in 1909. As a reminder, normal highs for early February are mid to upper 30s and lows upper teens and low 20s.
Those yearning for winter conditions will not appreciate the forecast for the second-half of the week. A few showers do linger Wednesday morning in the wake of a passing cold front. But, high pressure settles in for the rest of Wednesday and first-half of Thursday. Forecast soundings point to a fairly dry atmosphere along with deterministic and ensemble forecasts. PWATs (Precipitable Waters) are generally less than two tenths of an inch through Wednesday night, not expecting any real weather during this period. Sky cover remains mainly clear Wednesday through Wednesday night, increasing clouds by Thursday morning.
Weather becomes unsettled Thursday into Friday as a vertically stacked low pressure system travels through the Great Lakes and moves northeast into southern Canada. Given how far inland the system is, once again to be a mainly rain event. Isolated snow or wintry mix are possible Thursday afternoon as a frontal boundary lifts north. Areal coverage at this time would be limited to the higher elevation of northern and western Massachusetts. For what it is worth, forecast sounding at KORE [Orange, MA] does have an hour or two of -SN before changing over. Lower confidence in coverage of showers on Friday, deterministic guidance would support the precipitation ending in the morning... But the ensembles would continue it. Given lower confidence during the day Friday, left POPs at chance.
Looking ahead at the upcoming weekend, guidance would like to place a surface low off the coast of southern New England. GFS (Global Forecast System) running a bit on the warmer side, versus a colder Euro solution. Pounds of time, so stay tuned!
Forecaster Confidence Levels:
Low - less than 30 percent. Medium - 30 to 60 percent. High - greater than 60 percent.
Tonight through Tuesday night
Gale force wind gusts gradually diminish during the hours following midnight. Northeast winds continue to weaken throughout the day tomorrow as high pressure builds over the region. A cold front will push through the region late tomorrow night with scattered showers and 20 to 30 knot wind gusts out of the west.
Outlook /Wednesday through Saturday/... Thursday: Winds less than 25 kt. Seas locally approaching 5 ft. Chance of rain.
Thursday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Local rough seas. Rain, patchy fog.
Friday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Chance of rain.
Friday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas. Chance of rain, patchy fog.
Saturday: Moderate risk for Small Craft Advisory winds with areas of gusts up to 30 kt. Areas of rough seas. Chance of rain.
Saturday Night: Moderate risk for gale force winds with gusts up to 35 kt. Rough seas up to 9 ft. Slight chance of rain.
Sunday: Low risk for gale force winds with gusts up to 35 kt. Areas of rough seas.
NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...None. RI...None.
Small Craft Advisory until 1pm EST Tuesday for ANZ230-233>237. Small Craft Advisory until 7pm EST Tuesday for ANZ231-232-251. Gale Warning until 5am EST Tuesday for ANZ250-254-255. Gale Warning until 3am EST Tuesday for ANZ256.