Marine Weather and Tide Forecast for Ipswich, MA

NEAR TERM /UNTIL 6 AM THIS MORNING/
1010 PM update...

Mid-high clouds overspreading SNE which has prevented a sharp temp drop. However, may see some partial clearing develop overnight with a small window for a further cooling. Looking at lows mostly zero to 10 above, with teens outer Cape/ACK and Boston metro.

The risk for black ice development for Cape/Islands appears low at this time. Dewpoints expected to remain in the single numbers here tonight, rising into the mid teens toward daybreak at ACK and outer Cape where temps expected rise into lower 20s. T/Td depressions should remain large enough to preclude any condensation developing and freezing on area roadways.

Previous discussion...

Key Messages:

* Dry, though with increasing mid to high clouds.

* Outside chance at black ice for southeast New England?

Generally tranquil/dry conditions tonight, and while still colder than normal we're not expecting conditions to be nearly as cold as the last few nights. An expanding layer of mid to high clouds now starting to advect in from the west will help facilitate that. Although we will see an early period of cooling, the coverage of cloudiness should be widespread enough to stunt further cooling. Still looking at lows in the single digits to the lower to mid teens though.

What is less clear is the potential for some patchy slippery spots, mainly over southeast MA/RI, in response to increasing moisture levels. Very dry over most of interior New England (e.g. dewpoints down to 5 to 10 below), with little recovery anticipated. However the one area to watch for possible slippery spots is in southeast New England, with the vast majority of models showing dewpoints rising into the lower to perhaps mid teens on increased light southerly flow. Forecast dewpoints are near current temps. We've seen instances where condensation occurs as dewpoints rise coming out of frigid, Arctic airmasses and leaves a shallow layer of moisture on cold pavement which could become slippery. Not a good sense if we see this development or what the coverage could be, but it wouldn't surprise me if there was patchy instances of black ice over southern RI, southeast MA and the Cape and Islands as dewpoints start to rise/recover as winds become southerly.

Previous discussion:

High pressure and mid level ridge move offshore to the east tonight, with weak shortwave energy and mid level warm front moving through.
Increased moisture is expected with the warm front, but with little to no upper level support, noting more then increased mid to high level cloud cover is expected tonight. With little to no wind and cold air still in place, low temperatures should bottom out in the single digits again across the interior, and low teens near the coasts.

SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/
Better upper level forcing arrives Thursday in the form of a weak short wave, but by this time, the better mid level moisture will have moved off to the north east. With drying mid levels, not expecting any precip inland, but a weak low spinning up offshore could bring some light snow to the Cape and Islands tomorrow. Most guidance keeps the snow offshore tomorrow, but a couple of the hi- res guidance sources do show 1-2 inches possible on the Cape and Islands. Given the shallow moisture profiles, I think these values are a bit bullish, but a 1/2 inch seems more likely if it ends up snowing. With warming 850mb temps to -10C, and SW surface winds, high temperatures will be able to warm into the upper 20s to low 30s.

High pressure builds back overnight, allowing for clearing skies and calm winds. With good radiational cooling conditions, overnight low will again drop into the single digits to low teens.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
Key Messages:

* Rather benign weather in the offing for late January standards this forecast period; other than a passing Clipper system Sun which could bring passing snow showers, dry weather prevails into early next week.

* Fri and Sat feature colder than normal temperatures before rebounding back to near/slightly above normal levels for Sunday.

* Early next week outlook favors continued dry weather with temperatures around normal.

Details:

Overall no substantive change to the forecast and messaging in this portion of the forecast. Southern New England will be entrenched in what is climatologically the coldest portion of the calendar year during this forecast period.

This forecast period will continue be governed by the northern stream of a split-flow pattern at 500 mb, with mean troughing over the central and northeastern US and a trough/closed low feature over the southwest CONUS. Other than passing snow showers in association with a Clipper low moving in on Sunday, dry weather looks to be the theme.

Will see a period of colder than normal temps Fri and on Sat, highs mid 20s to around freezing with lows in the single digits Fri night.
But this shot of cold air does not look to be nearly as stout as the colder airmass working its way over Southern New England today.
Warmest day of this period then takes place on Sunday with highs in the low to mid 30s with some sunshine ahead of the 2nd clipper system Sunday, which then cools us off to around seasonable temperatures into Mon and Tue.

AVIATION /06Z THURSDAY THROUGH MONDAY/
Forecast Confidence Levels:

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

06z TAF Update:

Through 12z...

VFR cigs with light wind. Patchy MVFR cigs possible Cape/Islands.

Today...High confidence.

VFR cigs with patchy MVFR and a few snow showers possible over Cape/Islands. Clearing from W to E during the afternoon. SW wind around 10 kt.

Tonight and Friday...High confidence

VFR. Light W-NW wind developing tonight, up to 10 kt Cape/Islands. NW wind 8-15 kt Fri.

KBOS TAF...High Confidence in TAF.

KBDL TAF...High Confidence in TAF.

Outlook /Friday Night through Monday/...

Friday Night through Saturday: VFR.

Saturday Night through Sunday Night: VFR. Breezy.

Monday: Breezy.

MARINE
Forecaster Confidence Levels:

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

Tonight:

Light and variable winds overnight less then 10 knots, except for extreme northern waters where winds will be SW at 10-15 knots.

Thursday...

Increasing WSW winds, at 10-15 knots. Low risk for a 25 knot gust in the northern waters, but confidence was not high enough to issue SCAs.

Thursday Night.

West winds continue at 10-15 knots.

Outlook /Friday Night through Monday/...

Friday through Friday Night: Winds less than 25 kt.

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

Saturday Night: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas.

Sunday: Moderate risk for Small Craft Advisory winds with gusts up to 25 kt. Areas of rough seas.

Sunday Night through Monday: Low risk for Small Craft Advisory winds with gusts up to 25 kt. Local rough seas.

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