textproduct: New York

SYNOPSIS

A winter storm impacts the region late today through Saturday morning. High pressure then briefly returns before a strong frontal system impacts the area late Sunday through Monday. The region will then remain between high pressure to the southwest and strong low pressure over southeast Canada Tuesday into Wednesday. A clipper low may track nearby next Thursday.

NEAR TERM /THROUGH SATURDAY/

What's Changed: Winter Weather Advisory has been upgraded to a Winter Storm Warning for Middlesex and New London counties in CT.

Key Messages:

* Winter storm impacts the area late today through Saturday morning, with a plowable snowfall likely.

* Heaviest snow is expected to occur this evening, with significant travel impacts expected due to reduced visibilities and snow covered roads.

* Snowfall accumulations range from 6 to 10 inches across the area. Localized areas could reach 1 foot of snowfall accumulation where heaviest banding sets up.

No significant changes to forecast thinking with this update aside from increased confidence in high snowfall rates and a slight increase in total snowfall accumulation.

A winter storm is expected to impact the region later this evening and tonight, producing one of the larger snowfalls in the past several years for some areas.

Mid level shortwave rounds ridging centered over the Central US, with associated surface low pressure tracking east through the OH Valley. Strong frontogenetic forcing, coupled with ideal jet positioning, develops widespread snow across the area by this evening. Continue to think this will be a primarily all snow event for most, though still a low chance that sleet mixes in across portions of the area with WAA aloft. Soundings depict a warm nose above H7 that if slightly undermodeled, could allow for more in the way of ice pellets, particularly for NYC and points south and west. This potential is currently not expected to impact snow accumulations, as any sleet looks to occur after the period of heaviest snowfall and occur intermittently rather than a complete changeover.

Bulk of the accumulation looks to occur this evening and into the first half of the night when the strongest thermal forcing, omega, and synoptic lift coincide, leading to heavy snow banding. Hi res 12Z guidance has narrowed in on the most likely corridor for the heavy snowband to set up, which appears to be starting in LowHud & N Fairfield, then extend southeast down into Central and Eastern Long Island. There is still some wiggle room for this to change, but this appears to be the most likely location for the snowfall band to set up. Under this snowband is the risk for the highest snowfall rates. continues to wiggle this axis around, but consistently signaling it sets up over the local area, with the 12z HREF offering notable 10- km neighborhood probabilities (80-100%) of greater than 1 inch per hour rates from around 6-9 PM for NYC metro on NW, then shifting south and east through midnight. Localized pockets even exceed 50% for 2 inches per hour in this window. This leads to growing confidence in heavy snowfall rates for several hours after sunset into the first part of the night.

The heavy snow band will gradually subside overnight as the lift weakens and saturation aloft begins to wane. Light snow accumulation is still expected through early to mid Saturday morning, although the rates will likely be much lower, more on the order of a quarter to half inch per hour.

Upgraded the Winter Weather Advisory to a Winter Storm Warning in Middlesex and New London counties in CT. The overall axis of heavy snow has shifted slightly northward, which means snow totals will be higher in these locations. While snowfall totals reach 6-8" in parts of Union, Essex, Hudson, and NYC, these areas could only reach borderline warning criteria given the axis of heavier snow being shifted northward.

Snowfall Accumulations: Overall, 6 to 10 inches are forecast with localized amounts nearing 1 foot, possible. The higher amounts are possible if banding were to put down a bit more snow or linger longer over specific areas than currently anticipated.

If the forecast verifies, Central Park will receive its first snowfall of greater than 4 inches since January 2022. In the January 28-29, 2022 storm 8.3 inches was observed.

Snowfall rates: Peak rates of 1-2 inch per hour are expected in heavier snow bands. Rates could briefly exceed 2 inches per hour in heaviest snow banding, which appears to be very localized.

Snow characteristic: Likely going to be variability with snow ratios throughout the event, but the snow may begin a bit drier and become wetter as the event wears on. The banding potential also complicates this as within the band ratios will likely be high but in areas surrounding the band could be lower.

Light snow or flurries likely persist through much of Saturday morning before tapering off by midday or so. Additional accumulation after 12z continues to look insignificant. Clouds may linger into the afternoon, but clearing does start to take place later in the day from the north. With the fresh snowpack, temperatures likely struggle to rise above freezing on Saturday.

SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/

Saturday night, high pressure noses in from the north, then settles over the area early on Sunday before retreating to the south later on Sunday. Dry weather is expected during this period.

It remains cold Saturday night with lows in the teens inland to low 20s along the coast.

A strong frontal system begins to impact the area late Sunday into Sunday night. Temperatures will be below freezing in the interior prior to a warm front passing. Its possible that there may be a period of time for freezing rain to occur in the interior parts of the Lower Hudson Valley and southern Connecticut Sunday evening into early Sunday night before temperatures warm up enough to see a transition to all rain. There is still some variablity around just how much of this ice could accumulate before temperatures rise above freezing. Other areas of the CWA will start and remain rain Sunday evening into Sunday night.

LONG TERM /MONDAY THROUGH FRIDAY/

Key Messages:

* A strong cold front moves across the area on Monday with continued high probabilities of rain, especially in the morning.

* Gusty winds develop behind the cold front Monday night through Tuesday, with potential of gusts approaching or exceeding 40 mph.

* Mild temperatures on Monday (Upper 40s to lower 50s) will trend much colder for the rest of the week with highs in the lower to mid 30s, potentially not rising above freezing on Tuesday and then again at the end of the week.

Plain rain is expected everywhere on Monday morning. The systems warm front lifts north of the area and there is chance the precip diminishes in the afternoon. Continued to go with the NBM for now, but any precip Monday afternoon may become showery and scattered. A few showers are also possible with the strong cold front passage late in the day.

The cold front moves offshore Monday night ushering in much colder air and gusty winds as the region will lie between building high pressure to the south and west and strong low pressure to our north and east. This tight pressure gradient will remain in place through Tuesday. Wind gusts 40-45 mph are possible Monday night through Tuesday. Given recent NW flow events in strong cold and dry advection, it would not be surprising to see gusts peak up to 50 mph. Will continue to monitor trends over the next few days. Winds begin weakening Tuesday night, but breezy conditions are likely to remain for much of the week.

The larger scale pattern after the cold front passage favors upper troughing over the eastern US which will help keep colder air in place to start 2026. Dry conditions are currently forecast. There is a chance of a clipper system passing sometime late week, but the latest model consensus keeps conditions dry at this time.

OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY

Saturday PM: Improving to VFR, likely by sunset.

Sunday: VFR during the day. IFR and rain at night, possibly starting as a wintry mix north of the city terminals in the evening.

Monday: IFR with rain/showers, Improving to VFR late day/early evening. SW winds G20-25kt.

Tuesday: VFR. W winds G25-30kt.

Wednesday: VFR. W winds G20-25kt.

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

MARINE

Seas remain below SCA-criteria through much of tonight. Early tomorrow morning SCA conditions return on ocean waters as seas reach 5 ft under a gusty 25 kt flow. Conditions fall below SCA- levels by the evening. Sub-SCA conditions are then expected Saturday night through Sunday night.

SCA conditions are likely on Monday on all waters ahead of a cold front passage. Gales are becoming increasingly likely on all waters Monday night through Tuesday night. Conditions begin to improve into midweek, but SCA conditions may linger through much of the week.

HYDROLOGY

No hydrologic impacts are expected through mid next week.

OKX WATCHES/WARNINGS/ADVISORIES

CT...Winter Storm Warning until 1 PM EST Saturday for CTZ005-009. Winter Storm Warning from 7 PM this evening to 1 PM EST Saturday for CTZ006>008-010>012. NY...Winter Storm Warning until 1 PM EST Saturday for NYZ067>075- 078-080-176>179. Winter Storm Warning from 7 PM this evening to 1 PM EST Saturday for NYZ079-081. NJ...Winter Storm Warning until 1 PM EST Saturday for NJZ002-004- 006-103>108. MARINE...Small Craft Advisory from 5 AM to 10 PM EST Saturday for ANZ350-353-355.