Marine Weather and Tide Forecast for West Haven, CT

NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/
The forecast is mainly on track. Only minor adjustments to hourly temperatures and dewpoints were made with this update.

Confluent zonal upper flow aloft across the region, with broad sheared polar trough extending from the northern plains to northern New england. At the surface, the tight pressure gradient slowly relents as high pressure builds towards the Mid Atlantic and large Canadian Maritimes low pressure lifts towards Greenland.

Pressure gradient will gradually weaken tonight as a result, with gusts falling back into the 15 to 25 mph range. Low temperatures will fall into the single digits far interior, to teens along the coast, with min windchills in the single digits city/coast and single digits degrees below zero across the interior.

SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/
* Model consensus continues to point towards deepening low pressure tracking well south and east of the region Thursday, with a light dusting of snowfall the most likely scenario in response to approaching vigorous closed upper low.

Confluent and zonal upper flow gradually amplifies Wed into Wed night ahead of a deepening northern stream closed low digging through the upper Mississippi River Valley and into the Ohio Valley.
Good agreement on this vigorous closed low sliding just south of the region late Thursday into Thursday Night. Meanwhile a southern stream shortwave across the Lower Mississippi River Valley Wed AM (bringing snow to the southern plains and Mid Mississippi River Valley today) races towards the Mid Atlantic coast by Wed eve, with a second southern stream shortwave racing around the digging northern stream closed low to the southern Mid Atlantic coast by Thu AM.

As has been the case over the last 48 hours, overwhelming deterministic/ensemble model consensus is that the two streams never partially or completely phase until they are both well east of the region. The result is very good agreement in southern surface low pressure tracking to the SE US coast late Wednesday, and then intensifying as it tracks northeast and offshore Thursday into Thursday Night, 300- 450 miles se of Long Island. The result being that most if not all the precip shield with the offshore low remains to the SE of the region (perhaps clipping SE LI THU AM). The potential for a period of light snow or snow shower activity will be more-so coincident with the approach/passage of the vigorous upper low and some moisture convergence along weak inverted troughing Thu aft/eve.

The few exceptions to this consensus are the 12z 32/12km NAM deterministic runs, which although fairly similar in upper dynamics through daybreak Thu AM, rapidly develop surface low pressure with an abrupt jog about 150 miles close to the coast THU AM compared to rest of model guidance. Interestingly this is not seen in the high- res 3km NAM CAM. A possible reason for the outlier NAM 12km/32km NAM surface solutions may be the convective parameterization schemes used in these runs (and not the 3km NAM) firing off abundant convection as the 150kt+ upper jet streak overspread the gulf stream and general low position.
The 12z 32/12km NAM solutions, for reference bring close 1/4" to 1/2" liquid to the coast (around 4 to 7" snowfall), but for the above mentioned reason and lack of support this scenario is considered an outlier.

The 18z NAM has trended further south and less intense with the surface low, but still indicating potential for a widespread 1/10th to 1/4" qpf along the coast. This downward trend, in line with consensus guidance, is anticipated to continue over the next 24 hrs, but it is worth noting that this solution falls in line with other reasonable worst case scenarios. The source of enhanced snowfall appears to be coming from enhanced lift from the left front exit region of a more cyclonically curved jet streak and NW enhancement of offshore low pressure precip shield. Outside of the 18z NAM 12km/32KM, a few 12z SREF NMMB, GEFS, and ECE members indicate some snowfall solutions in the 3 to 5" range for eastern LI and extreme SE CT, in line with a reasonable worst case scenario.

So, current thinking is potential for a period of light snow or snow showers Thu afternoon into Thursday evening in response to the deepening closed low and weak inverted trough in vicinity.
Snow accumulation generally less than an inch areawide, with potential for an inch or so for extreme SE portions of the area where fringe of offshore snow shield may glance. Reasonable worst case WPC WSE and NBM (1 in 10 chance of occurrence), capturing 18z NAM 12/32km and other outlier ensemble members, would be a 2-5" snowfall across eastern LI and SE CT.

Remaining cold, region largely sub freezing with highs in the mid 20s interior and upper 20s to around 30 city/coast on Wed and Thu.
Winds are expected to be lighter than previous days with the high more established and a relaxed pressure gradient in response.

LONG TERM /FRIDAY THROUGH TUESDAY/
Remaining somewhat breezy on Friday as high pressure continues to build in from the west. Dry conditions with high temperatures 5-10 degrees below normal - in the lower and middle 30s. The high pressure ridge is expected to reach the east coast on Saturday.
Winds will be light and shift west to southwest, allowing for milder high temperatures, but still a little below normal.

A weak trough aloft shifts through the region late Saturday night into Sunday with perhaps some weak surface reflection. Moisture is lacking, and will go with a dry forecast for this period, however a sprinkle or flurry isn't completely out of the question. High temperatures on Sunday finally returning to normal at 40-45.

Weakening low pressure shifts east from the Great Lakes Region, likely passing to our north at some point Monday night into Tuesday.
A leading warm front and trailing cold front may support enough lift to bring us some precip. Capped PoPs at slight chance for the time being. Precip would be mainly rain for coastal areas and a mix of rain and snow inland.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
VFR as high pressure builds to the southwest.

WNW-NW winds mostly left of 310 magnetic 15-20 kt with gusts up to to 25 kt will hang on into this evening, then slowly diminish overnight. There could be a few hours' lull where winds diminish to either side of 10 kt and gusts abate before resuming around 13Z and continuing into at least the first part of the afternoon. Winds gradually diminish late as BKN mid level clouds move in.

...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...

No unscheduled AMD expected.

OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY

Wednesday night: VFR.

Thursday: Chance MVFR or lower in light snow mainly for the terminals E of the NYC metros, otherwise VFR. NW winds G20-25kt at night.

Friday: VFR. NW winds G20-25 kt.

Saturday and Sunday: VFR.

Detailed information, including hourly TAF wind component forecasts, can be found at: https:/ www.weather.gov/zny/n90

MARINE
Winds expected to fall below Gale across eastern ocean waters later this evening, with conditions falling below SCA late tonight on nearshore water and Wed AM for the ocean waters.
Ocean seas (NW Wind wave dominated) expected to follow suit and fall below SCA Wed AM as well.

Light freezing spray possible everywhere through Wednesday morning as well, but not anticipating it to be heavy enough to necessitate an advisory.

Next chance of SCA conditions late Thursday into Friday in wake of rapidly deepening offshore low pressure as it tracks northeast up into the North Atlantic.

Advisory conditions continue through Friday for all waters, then will be limited to mainly the ocean through Friday night.
Sub advisory conditions then prevail through the upcoming weekend with a weaker pressure gradient as a high pressure ridge is followed by a weak trough.

HYDROLOGY
No hydrologic impacts are expected through the week.

TIDES/COASTAL FLOODING
Low water conditions expected to improve for the evening low tide ( 1 to 1.5 ft below MLLW) as offshore winds weaken a bit. Further improvement expected with Wed high tides with continued weakening of winds and rising of astro low tides.

OKX WATCHES/WARNINGS/ADVISORIES
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 7 AM EST Wednesday for ANZ331-335- 338-345.
Small Craft Advisory until 10 AM EST Wednesday for ANZ332-340.
Gale Warning until 10 PM EST this evening for ANZ350.
Small Craft Advisory until 1 PM EST Wednesday for ANZ353-355.