Marine Weather and Tide Forecast for Norwalk, CT

KEY MESSAGES
1) A light snowfall across parts of the region tonight may lead to hazardous travel conditions Monday morning, particularly for the NYC metro, northeast New Jersey, and much of Long Island.

2) Progressive low pressure systems will bring rain/snow/mixed precip chances mid to late week. Predictability details on precip type remain low at this point.

DISCUSSION

KEY MESSAGE 1

The forecast picture continues to sharpen for tonight into Monday.
A northern branch shortwave diving into New England attempts to phase with a southern stream low translating east through the Deep South. Despite adjustments in guidance and varying solutions over the past day or two, it's become more apparent the interaction is largely too little too late locally, though still enough to graze the region with a period of light precipitation tonight as the surface low passes east well to the south off the Mid Atlantic coast.

Thermal profiles support predominantly snow, though marginally so.
Surface air temps are likely near freezing through much of the event, and may even remain just above it around the NYC metro.
The snow looks to develop from the south and west this evening, after 8pm or so, overspreading the rest of the coast into late evening. Not out of the question a few raindrops fall to start around the NYC metro and south shore before wet bulbing cools the column. Periods of light snow are then likely for coastal areas into the night, with less coverage going north and east as soundings indicate a good deal of dry air at H925 across southern New England, likely limiting the northern extent of the precip shield. Across SE CT, and perhaps most of S CT, locales may remain entirely dry, or only see a few flurries.

Short range hires ensembles yield QPF generally around or just above a tenth of an inch along the southern coast, with less than a tenth going into S CT. Given the marginal profile, SLRs will likely be near or under 10:1. Forecast totals have not changed significantly with this update. Still anticipating around an inch for the NYC metro, NE NJ, much of Long Island, and perhaps even into the LoHud Valley, with lesser to little going north and east. Reasonable worst case (90th percentile)
remains around 2 to 3 inches. Conversely, its still possible the snow simply doesn't fall hard or steady enough to yield much in the way of accumulation.

Given the low totals, no advisory warranted with this update.

Overall not a significantly impactful event, but the light snow may lead to some icy travel conditions overnight and into Monday morning. Extra caution should be used during this time.


KEY MESSAGE 2

A warm front will approach Tue night into Wed, then a trailing cold front will pass south Wed night into Thu. PoP remains likely to categorical for Wed afternoon/night as low pressure may form along the boundary and pass over or south of the area. Some spotty light freezing rain may be possible at the onset well north/west of the area for any precip that arrives earlier during Wed morning. QPF with this system should range from 1/4 to 1/2 inch, highest inland.

PoP for Thu/Thu night only slight chance as the front should pass S and high pressure may briefly nose in from ern Canada, then increases to likely on Fri as the front returns N as a warm front as the high retreats and as parent low pressure moves from the N Plains to the upper Great Lakes, and as another low forms along the boundary to our south. QPF with this system will be a little over 1/2 inch area-wide.

Daytime highs should be in the lower/mid 40s, with nighttime lows mostly in the 30s closer to the coast and 20s to lower 30s inland.

AVIATION /00Z MONDAY THROUGH FRIDAY/
High pressure over the Northeast will retreat some as low pressure passes well south and east of the terminals late tonight into Monday. This will place the area on the northern periphery of the low with a chance for some light snow. The best chance will be across the NYC terminals and KISP.

MVFR/IFR conditions develop in light snow overspreading the area from SW to NE. IFR conditions will likely be confined to the NYC and KISP terminals where there is a better chance to see the snow. MVFR is more likely elsewhere with KGON possibly remaining VFR for the entirety of the event due to drier air associated with the aforementioned high over the Northeast. Snow tapers and ends from the west 09-11Z.

Snow accumulations are expected to around 1 inch at the NYC and KISP terminals. Less than an inch elsewhere, especially for far north and northeast terminals.

E/NE winds during tonight. Winds generally around 10 kt at the coast, and less than 10 kt elsewhere. N / NE winds Monday, generally settling in around 5 to 10 kt during the afternoon. A few gusts 15-18kt possible at the coastal terminals overnight into Monday morning.

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

Amendments of 1-2 hours are likely for category changes due to onset and ending of light snow.

OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY

Monday Night-Tuesday: Low chance of MVFR or lower in a light wintry mix after midnight into Tuesday AM.

Wednesday: MVFR or lower possible in mainly rain.

Thursday: Mainly VFR.

Friday: MVFR and lower possible in mainly rain, mix possible north.

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

MARINE
Low pressure passes south of the waters tonight into Monday, and could lead to occasional 25 kt gusts on the ocean during the morning hours.

Otherwise, sub SCA conditions on all waters until Monday evening, as ocean seas build toward 5 to 6 ft. SCA conditions then likely persist on these waters through at least Tuesday evening, if not into midweek.

OKX WATCHES/WARNINGS/ADVISORIES
CT...None.
NY...None.
NJ...None.
MARINE...None.