Marine Weather and Tide Forecast for Melville, RI

KEY MESSAGES

- Rain ongoing today will transition to sleet and freezing rain across the higher terrain heading into the evening hours, along with areas north of I-90. Precipitation expected to last through Friday morning. Greatest risk for 0.25"+ ice accretion remains in the high terrain of the southern Worcester Hills and southern Berkshires. Plowable snow more likely in far NE MA. Lingering drizzle as precip tapers off Fri afternoon.

- Turning milder with a warming trend this weekend and increasing risk for showers Sat night into early Sun as a cold front approaches.

- Potential for a few days of unseasonably mild conditions next week but have to watch a backdoor front to the north which would bring much cooler temps. Accelerated snowmelt will lead to steady rises on rivers and streams through the week. A period of showers accompany a cold front late Wed-Thu, then turning cooler towards the end of the week.

DISCUSSION
KEY MESSAGE 1...Rain ongoing today will transition to sleet and freezing rain across the higher terrain heading into the evening hours, along with areas north of I-90. Precipitation expected to last through Friday morning. Greatest risk for 0.25"+ ice accretion remains in the high terrain of the southern Worcester Hills and southern Berkshires. Plowable snow more likely in far NE MA.

A low from the west will continue tracking towards the south coast today into tonight, bringing with it a mix of rain, snow, sleet, and freezing rain.

Rain is making its way through southern New England at this time, with rain slowly moving north and east, being somewhat suppressed in northern parts of the region by lingering dry air aloft. More rain will move in during the evening hours and into tonight where the forecast becomes a bit messier, as ptype will transition from mostly rain to more sleet and freezing rain. This mix will mostly impact areas north of I-90 along with the higher terrain in the southern Worcester Hills and Berkshires, where the colder temperatures towards the surface resulting from the shallow cold air will allow for refreezing of falling precip. As a result, the chances for ice accretions reaching 0.25"+ are highest there, which could lead to power outages in these areas.

Latest guidance continues to support more of a glaze of ice and sleet for northern MA, as 925 mb temperatures remain around -3C to -5C, but 850 mb temperatures are closer to and above 0C.
Latest forecast soundings still have air below freezing extending up to around 5000 ft for northern MA for the first half of tonight, favoring more sleet. Past midnight, the guidance shifts to more snow as the air around 850 mb falls below 0C and the column becomes isothermal. Some sleet being mixed in with this snowfall cannot be completely ruled out. The latest HRRR showed this trend well, favoring more snow for NE MA and down into Boston. Snow totals in NE MA could reach up to 4"; snow and sleet accumulations further south into the Boston area could range between 2-3".

Precipitation is expected to taper off heading into the afternoon Friday, but light rain/drizzle and some fog will likely stick around, especially in the eastern half of southern New England due to continued onshore flow. These NE winds will keep the lower level moisture in place over the area, leading to a mostly dreary day Friday.

KEY MESSAGE 2...Turning milder with a warming trend this weekend and increasing risk for showers Sat night into early Sun as a cold front approaches.

Surface ridge across New Eng Sat will move offshore with a S-SW flow developing in the afternoon. This will bring milder temps than Fri but certainly not as mild as 925/850 mb temps would suggest.
Soundings show a rather strong inversion just off the deck with abundant low level moisture so expect lots of clouds with very shallow/limited BL mixing. So while it will be milder, the shallow cooler air will linger likely holding temps in the low-mid 40s. A cold front approaches from the NW Sat night and moves into SNE during Sun. A modest pre-frontal LLJ develops which advects higher PWATs exceeding 1" into SNE leading to some showers later Sat night into Sun morning, but widespread rain not expected. Then it should dry out by the afternoon with sunshine developing from NW to SE as the column dries out from the north. However, clouds should persist along the south coast as the moisture plume lingers here. Still a shallow mixed layer Sun but it's drier with westerly flow which should help to boost temps into the 50s.

KEY MESSAGE 3...Potential for a few days of unseasonably mild conditions next week but have to watch a backdoor front to the north which would bring much cooler temps. Accelerated snowmelt will lead to steady rises on rivers and streams through the week. A period of showers accompany a cold front late Wed-Thu, then turning cooler towards the end of the week.

A quasi-zonal flow sets up across the northern CONUS with a series of low amplitude shortwaves moving through the flow. A broad SW flow will allow further warming Monday with the potential for unseasonably mild to perhaps warm conditions on Tue and Wed.
However, this is not a certainty as high pres will be across eastern Canada with a backdoor front lurking to the north. GFS is trying to push the front southward with shallow cool air draining south into SNE later Tue into Wed and GEFS overall is leaning on the cooler side. Meanwhile ECMWF keeps the front to the north with unseasonably mild temps. Interesting that AIGFS is all in on the warmth for Tue- Wed. We followed the NBM temps which has temps in the 60s away from the south coast. Confidence in temps is moderate and warmer temps will depend on front remaining to the north. 925 mb temps are pretty mild and it's not out of the question we could see a few 70+ readings in the CT and Merrimack valley both Tue and Wed if the front stays to the north. EC ENS indicate 20-40% prob of 70+ Tue & Wed. These warmer temps combined with dewpoints climbing through the 40s and possibly some 50s by Wed will promote accelerated snowmelt with steady rises on rivers and streams. In addition, a period of showers will likely accompany a cold front late Wed into Thu. MMEFS ensemble guidance from the NAEFS and GEFS indicate a low risk for some rivers reaching minor flood next week so we will have to monitor this closely. The cold front is expected move through sometime Wed night into early Thu followed by cooler and drier conditions.

AVIATION /19Z THURSDAY THROUGH TUESDAY/
Forecaster Confidence Levels...

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

18z TAF Update...

Rest of Today...Moderate confidence.

Widespread MVFR-IFR with localized LIFR conditions expected to overspread the region from southwest to northeast as the afternoon goes on, but mostly VFR north of the MA/RI/CT border at this time. Pockets of light rain already impacting CT/RI/SE MA. The rain is slowly to advancing north, and some showers are already making their way into Middlesex Co. in MA. ORH is currently reporting rain as well, but still seeing VFR conditions that may deteriorate over the next few hours. The rain may also begin to mix with sleet this evening near and north. NE winds increasing to between 5 and 15 knots during the afternoon with the strongest of those winds near the coast.

Tonight and Friday...Moderate confidence.

IFR/LIFR conditions dominate in freezing rain and sleet in areas north of I-90 as well as parts of the high terrain tonight. Sleet will probably be favored over freezing rain to the north of I-90 by the mid evening hours. South of I-90 in the lower elevation, ptype mainly will be rain but some sleet may be mixed in at times. Ptype may mix with or change to snow late tonight into Fri morning for northern MA with the greatest risk north of route 2 into into northeast MA near the NH border. The risk for snow has also shifted slightly south into BOS after midnight. Precipitation tapers to mainly light rain/drizzle by Friday afternoon but IFR/LIFR conditions likely persist along with areas of fog due to continued onshore flow. NE winds 5 to 15 knots with some 20-25 knot gusts possible near the coast.

Friday Night...Moderate confidence.

Mostly IFR. Winds weaken, but remain NE. With all the moisture left behind by the Thu night/Fri system, widespread areas of fog are a possibility overnight. Low chance for some precip for northern and western MA into central CT in the early morning hours of Saturday.

KBOS Terminal...Moderate confidence in TAF.

KBDL Terminal...Moderate confidence in TAF.

Outlook /Saturday through Tuesday/...

Saturday: Mainly IFR, with areas VFR possible. Breezy. Slight chance FZRA.

Saturday Night: MVFR/IFR conditions possible. Breezy. Chance RA.

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

Sunday Night: VFR.

Monday: VFR. Breezy.

Monday Night through Tuesday: VFR.

MARINE
Forecaster Confidence Levels...

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

Through Friday Night...High confidence.

Low pressure continues to approach from the west this afternoon and will pass to our south Friday morning. At the same time, a 1040+ mb high pressure system will build across Quebec.
Increasing NE winds this afternoon will continue through Friday before easing up Friday night as high pressure shifts more south.
NE wind gusts of 20 to 30 knots expected this evening will continue at times into Friday, so Small Craft Advisories remain in effect. Seas will also become quite choppy, ranging between 6-8 ft.

Outlook /Saturday through Tuesday/...

Saturday: Winds less than 25 kt. Areas of rough seas.

Saturday Night: Moderate risk for Small Craft Advisory winds with gusts up to 30 kt. Rough seas up to 8 ft. Chance of rain.

Sunday: Winds less than 25 kt. Seas up to 5 ft. Slight chance of rain.

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

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

BOX WATCHES/WARNINGS/ADVISORIES
CT...Winter Weather Advisory until noon EST Friday for CTZ002>004.
MA...Winter Weather Advisory until noon EST Friday for MAZ002>015- 026.
RI...Winter Weather Advisory until noon EST Friday for RIZ001-003.
MARINE...Small Craft Advisory until 7 PM EST Friday for ANZ231>235-237- 254>256.
Small Craft Advisory until 7 PM EST Friday for ANZ250-251.