textproduct: New York

SYNOPSIS

High pressure retreats north today as low pressure in the Midwest moves east. The winter storm impacts the region late today through Saturday morning. High pressure then briefly returns before a strong frontal system tracks through the Great Lakes, impacting the local area Sunday through Tuesday. A clipper low may track nearby into midweek.

NEAR TERM /UNTIL 6 PM THIS EVENING/

Key Messages:

* Arctic air mass settles in ahead of incoming winter storm.

Colder start than recent mornings with temperatures in the teens and 20s to begin the day thanks to CAA behind a fropa last night. Dry conditions persist through mid afternoon with light northerly surface flow. Afternoon temperatures top out at or below the freezing mark, with highs ranging from mid 20s well inland to lower 30s along the coast.

The Canadian high that ushered in this colder air mass retreats further north today as surface low pressure drives east through the Midwest. Thickening and lowering cloud deck expected into afternoon ahead of snow onset.

SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/

What's Changed: Winter Weather Advisory has been issued for New London County 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 5 to 9 inches in the Warning area and 3 to 5 inches in the Advisory. Localized areas could exceed 10 inches where heaviest banding sets up.

No significant changes to forecast thinking with this update. 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, but will have to be monitored.

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 guidance continues to wiggle this axis around, but consistently signaling it sets up over the local area, with the 00z HREF offering notable probabilities (50-80%) of greater than 1 inch per hour rates from around 7-10 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.

Expanded the Winter Weather Advisory into New London where snow amounts have increased slightly. Considered upgrade to Warning in Middlesex as well, though held off with lingering uncertainty on sufficient rates/amounts occurring so far east, and collaboration with neighbor. That said, an expansion of the Warning can't be ruled out should subtle shifts in the banding occur.

Snowfall Accumulations: Overall, 5 to 9 inches are forecast in the Warning area, with localized amounts exceeding 10 inches possible. In the Advisory area across SE CT, 3 to 5 inches is expected, with potential for a few locales to exceed 6 inches. 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. It remains cold Saturday night with lows in the teens inland to low 20s along the coast.

LONG TERM /SUNDAY THROUGH THURSDAY/

Key Messages:

* Strong low pressure brings rain to the region late Sunday through Monday, with a brief period of freezing rain possible across the interior at the onset Sunday evening.

* Gusty winds develop behind the storm on Tuesday, and gusts could approach or exceed 40 mph.

Strong frontal system continues to be the main story early next week, impacting the area late Sunday through Tuesday. The center of the low is progged to move over the Great Lakes region and rapidly deepen as it tracks into northern New England. Soundings indicate sufficient warm air advecting in aloft to preclude any snow from the system, but could see a period of ZR at precip onset with low level cold air in place initially. Area of concern for this is across parts of the interior, north and west of NYC. As the warm front approaches and milder air works in aloft, the ground across the interior likely stays right around freezing for some time, especially after being primed by a cold air mass for a several days. Guidance isn't signaling a significant ice threat from this event however, with accretion values well under a tenth of an inch. Plain rain is expected everywhere by the early morning hours of Monday, with rain continuing into the day.

As the system departs into eastern Canada, gusty NW winds develop behind it and speeds could approach or exceed 40 mph by Tuesday morning. Given a markedly colder air mass advecting in, wind chills likely fall into the teens at the least as well. Thereafter, a fast moving clipper low could pass near the region by Wednesday, though this system looks relatively weak and transient, and significant impacts don't appear likely.

OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY

Saturday: Snow ends in the morning. Improving to MVFR by noon, then to VFR during the afternoon day.

Sunday: MVFR/IFR with rain developing in the afternoon, continuing overnight.

Monday: MVFR/IFR with rain AM, improving in the afternoon. SW/W winds G25-30 kt.

Tuesday: VFR. W winds G25-30 kt.

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

MARINE

Small Craft Advisory remains on non ocean waters until 4 AM this morning, with ocean zones continuing until 10 AM. Winds and seas lighten through this time.

Winds and seas may approach SCA criteria on the ocean once again Saturday with gusts up to 25 kt and seas near 5 ft. Conditions improve Saturday evening, and then remain sub SCA through Sunday night.

Small Craft Conditions are likely Monday through Tuesday night on all waters as a low pressure system impacts the region. Gales are becoming increasingly likely Monday night through Tuesday. Gusts to 40 kt and ocean seas range 8-12 feet, with waves on the LI Sound reaching 5-7 feet during this time.

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 from 4 PM this afternoon to 1 PM EST Saturday for CTZ005-009. Winter Storm Warning from 7 PM this evening to 1 PM EST Saturday for CTZ006-010. Winter Weather Advisory from 7 PM this evening to 1 PM EST Saturday for CTZ007-008-011-012. NY...Winter Storm Warning from 4 PM this afternoon to 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 from 4 PM this afternoon to 1 PM EST Saturday for NJZ002-004-006-103>108. MARINE...Small Craft Advisory until 10 AM EST this morning for ANZ350- 353-355.