Marine Weather Net

Massachusetts Bay and Ipswich Bay Marine Forecast


REST OF TONIGHT

NW
WINDS
15 - 20
KNOTS

MON

NW
WINDS
15 - 20
KNOTS

MON NIGHT

NW
WINDS
15 - 20
KNOTS

TUE

NW
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
ANZ251 Forecast Issued: 1234 AM EST Mon Jan 20 2020

SMALL CRAFT ADVISORY IN EFFECT THROUGH LATE TONIGHT
Rest Of Tonight...Nw Winds 15 To 20 Kt With Gusts Up To 30 Kt. Seas 2 To 4 Ft. A Chance Of Light Freezing Spray.
Mon...Nw Winds 15 To 20 Kt With Gusts Up To 30 Kt, Diminishing To 10 To 15 Kt With Gusts Up To 20 Kt In The Afternoon. Seas 2 To 4 Ft. A Chance Of Light Freezing Spray.
Mon Night...Nw Winds 15 To 20 Kt, Diminishing To 10 To 15 Kt After Midnight. Gusts Up To 25 Kt. Seas 2 To 4 Ft. A Chance Of Light Freezing Spray.
Tue...Nw Winds 10 To 15 Kt With Gusts Up To 20 Kt, Diminishing To 5 To 10 Kt In The Afternoon. Seas 2 To 3 Ft.
Tue Night...Nw Winds 5 To 10 Kt. Seas 1 Foot Or Less.
Wed And Wed Night...Sw Winds 5 To 10 Kt. Seas Around 2 Ft.
Thu...Sw Winds 5 To 10 Kt. Seas Around 2 Ft.
Thu Night...W Winds 5 To 10 Kt. Seas 2 To 4 Ft.
Fri And Fri Night...N Winds 5 To 10 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.
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Area Forecast Discussion
National Weather Service Boston/Norton MA
Issued by National Weather Service New York NY
1232am EST Monday Jan 20 2020

Synopsis
Large high pressure building in from the west will result in dry, but cold weather today into Wednesday. As the high moves across the region late this week, temperatures will rise to above normal levels. Low pressure will push out of the mid Mississippi valley late this week, which may become a coastal low that could bring wet or wintry conditions to the region during next weekend.

Near Term - Through Today
Expect a mix of partly to mostly cloudy conditions crossing the region through the remainder of the night.

Temperatures at 05Z were mainly in the upper teens to mid 20s across the interior, ranging to the upper 20s to lower 30s along the immediate coast. W-NW wind gusts will also linger, up to 25-30 kt along the coast as well as the higher inland terrain and portions of the CT valley.

Near term conditions have been updated to bring current and incorporated into the overnight trends.

Previous Discussion... Our region remains between two major weather features, a deepening low pressure over the Maritimes, and a large high pressure over central Canada and the northern plains. Both of these features will be moving farther east tonight. This will result in a more northerly flow developing over our region. The main impacts of that will be the arrival of colder air, as well as some ocean-effect clouds across the eastern half of southern New England, especially across the Cape and Nantucket.

Temperatures expected to be near to slightly below normal for mid January. Temperatures slightly higher up and winds are marginal for ocean-effect snow showers late tonight. Winds may be just a bit to strong to develop significant bands. Any snow accumulation should be light.

Short Term - Tonight Through 6pm Tuesday
High pressure becomes more of a factor in our weather Monday into Monday night. Expecting mainly dry weather across most of southern New England. Still the risk for ocean-effect snow showers across the outer Cape and Nantucket Monday morning, diminishing MOnday afternoon. Thinking more clouds across the eastern half of southern New England during the morning. Should be mostly sunny all day across the western half. Mostly clear skies for Monday night.

Colder air arrives Monday, and continues into Monday night. Expecting below normal temperatures Monday. Winds might be a bit too strong to permit excellent radiational cooling. With dewpoints in the single digits, should winds diminish more than current forecast, could be looking at a very chilly night Monday night.

Long Term - Tuesday Night Through Sunday
Highlights... * Dry and cold on Tuesday

* Temps will moderate late Wednesday through Friday with continued dry conditions

* Low pressure moves out of the midwest Friday night, then may become a slow moving coastal low Next Weekend
appears to be mostly rain along the coast, but could see a mix and/or snow across the interior around late Sat into Sunday morning

Details... Tuesday... Progressive H5 trough moves SE across the region during the day, then offshore Tuesday night. H925 temps drop to -8C across the S coast to -12C off the eastern Mass coast. Several models signaling the possibility of some low level moisture that could produce light precipitation across the eastern waters late Tue/Tuesday night as the trough moves through. 12Z GFS is the most aggressive with the passage of this wave. However, PWATs (Precipitable Waters) are very dry, generally less than 0.25 inches. Plus, surface ridge axis lies from the coastal waters SWwd to the mid Appalachians with good subsidence in place. So, have kept a dry forecast going for now. Something to keep an eye on along the E coast.

With the cold pool(a region of relatively cold air) of air across the region, temperatures will not rise much during the day. Highs will be mainly in the 20s, though a few spots across the higher terrain may not reach 20, with some readings around 30 along the S coast.

Wednesday And Thursday
After the cold start Wednesday morning, the cold pool(a region of relatively cold air) at H925 and H85 will retreat to the N. The ridge will set up from NE-SW from the Maritimes across New England to the mid Atlantic and southeast states. The H5 ridge will also build above the surface high by around 00Z Thu across the eastern seaboard.

With the rising heigheights thanks to the ridging at the surface and aloft, temps will respond. Wednesday will be the transition day, with highs mainly in the lower-mid 30s, then will recover to the upper 30s to lower 40s on Thursday. Will see mostly sunny skies through most of this timeframe, but high clouds will start to filter in during Thursday afternoon.

Friday... 12Z model suite showing changes as a piece of mid level energy digs SE out of the northern Rockies, developing a cutoff H5 low pressure as it shifts SE to the south central Plains states by around 12Z Friday. The eastern seaboard ridge shifts slowly offshore as well, so will see a light SW flow developing.

Should see the mildest temperatures of the week with highs in the lower-mid 40s, around 5 to 10 degrees above normal. Mid level clouds should start to push in from the W during the day.

Saturday and Sunday... 12Z model suite and ensembles continue to signal the potential for low pressure moving out of the midwest late Friday, possibly redeveloping somewhere along the mid Atlantic coast during Sat which could bring a wintry mix of precipitation across portions of the interior sometime next weekend.

With this potential system in the long range timeframe, still quite large spread on the timing and track, as well as the overall thermal pattern and subsequent PTYPE issues. Models continue to signal the potential of a cutoff mid level system somewhere across the Great Lakes or Ohio Valley, as well as a digging trough along the W coast.

At this point, have carried mainly rain across most areas except snow well inland during the daylight hours, with temps falling which could bring a mix or change to snow closer to the coastal plain during Sat night. Still quite a few more model runs to determine the eventual outcomes for this potential event.

Marine
Small Craft Advisories continue on most waters this morning. Winds gradually diminish as a high pressure approaches the waters this afternoon into tonight. Seas will take longer to subside across the outer coastal waters tonight.

Light freezing spray will be possible early this morning with colder air moving across the waters. A few snow showers may affect Cape Cod Bay, Nantucket Sound and the waters east of Cape Cod.

Outlook /Tuesday Night through Friday/... Tuesday: Winds less than 25 kt. Seas locally approaching 5 ft.
Tuesday Night through Thursday: Winds less than 25 kt.

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

Friday: Winds less than 25 kt. Seas up to 5 ft.

NOAA Boston MA Office: Watches - Warnings - Advisories
CT...None. MA...None. RI...None.
MARINE...
Small Craft Advisory until 1pm EST this afternoon for ANZ231>234. Small Craft Advisory until 6am EST early this morning for ANZ230. Small Craft Advisory until 10am EST this morning for ANZ235- 237. Small Craft Advisory until 6am EST Tuesday for ANZ250-254-255. Small Craft Advisory until 1am EST Tuesday for ANZ251. Small Craft Advisory until 7pm EST this evening for ANZ256.