Marine Weather and Tide Forecast for Mamaroneck, NY

NEAR TERM /THROUGH TONIGHT/
For this midday update, dewpoints were adjusted to account for current observations being slightly lower than forecast. Winds were also adjusted to account for the latest guidance timing on today's sea breeze. Otherwise, the forecast remains on track.

High pressure is expected to gradually draw closer today and settle over the region tonight. This should lead to large scale subsidence overall. The upper level jet is progged to remain over Northern New England and into the Saint Lawrence River Valley up to the north. With the area on the southern side of the polar jet temperatures should continue to run above normal temperatures wise. Overall the synoptic flow will be NW based, but will be weaker than yesterday. Thus, by late this afternoon the expectation is for localized sea breeze development for most coastal locations. There remains some uncertainty to the extent of sea breeze advancement to the N and NW for the late afternoon and early evening. Maximum temperatures should get well into the 70s in most places. There will be 60s across coastal, especially eastern coastal communities. Went with NBM 90th percentile as far as max temperature forecast which is a few degrees above the deterministic and above a MAV / MET blend in most places.

High pressure settles over the area tonight with mostly clear skies and light winds. Temperatures are expected to bottom out in the 40s in the outlying areas, with some lower and middle 50s across the metro.

SHORT TERM /THURSDAY THROUGH FRIDAY/
High pressure slowly gets further east on Thursday. A return flow of sorts attempts to get going. With the synoptic flow expected to be fairly light, look for a hybrid sea breeze to develop with a southerly flow off the cooler ocean, especially for the afternoon.
By late in the afternoon a wide spread in temperatures should be anticipated, with mainly 60s and a few middle and upper 50s across coastal and eastern coastal sections, with 70s across western and interior locations. Temperatures are expected to be considerably cooler across eastern coastal sections for the late day and early evening with a wind off the colder ocean.

Subtle height rises are indicated by global NWP through Thursday night as the upper jet remains north of the region. Temperatures at 850 mb will remain around 10 C. However, with high pressure at the sfc over the Western Atlantic the low level winds will be southerly and this will bring in noticeably cooler air off the ocean. Winds will be light and more out of the SW and thus temperatures should remain quite mild Thursday night. However, more of an easterly component to the southerly flow likely kicks in during Friday. This will drive down max temperatures from the previous couple of days, especially further east. Temperatures to the west remain in question where 70s to perhaps up to 80 are a possibility for western and some interior locations, otherwise mainly 60s closer to the coast and to the east. If the sfc winds go more SE then temperatures even inland would be cooler than currently indicated. At this point there appears to be enough mid and upper level ridging taking place into Friday to keep the region dry, although a warm front back to the southwest may start to draw closer late in the day. This should lead to an increase in mid level clouds through the day.

LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
Some better agreement in the global models and their ensembles for the frontal system that impacts the area Friday night into Saturday.
Still though, the GFS is the faster of the operational members, but the gap is closing. Still staying close to the NBM as a consensus approach remains the best option. The focus still seems to hinge on the interaction of multiple pieces of northern branch energy dropping across central Canada toward the end of this week.

Expect the frontal system to bring showers into the area Friday night, with the most likely timeframe after midnight Friday through the first half of Saturday. Marginal instability could result in isolated thunderstorm, however, onshore flow and weak lapse rates should limit coverage. High pressure then builds in from the west Sunday into Monday. The next frontal system approaches from the mid section of the country on Tuesday.

Rainfall amounts at this time are likely to stay below an inch with NBM probabilities about 20 to 30 percent for an inch or more. The mean and median amounts are closer to half an inch.

Temperatures remain above normal into Saturday (5 to 10 degrees). A return closer to normal is expected Sunday, with a gradual warmup Monday into Tuesday ahead of the next system.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/
High pressure builds in from the west today and across the area tonight.

VFR through the TAF period.

NNW-N winds around 10kt this morning with a few gusts of 15-18kt.
The flow will then gradually back around to the WNW, with seabreeze or hybrid seabreeze development late morning into the afternoon at the coastal terminals. There is still some uncertainty with the seabreeze timing due model differences in the depth and strength of the westerly flow during the afternoon hours. Wind will then become light and variable Wednesday night.

...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
A few gusts this morning of 15-18kt possible.

Seabreeze timing could vary by 1-3 hours as there is some uncertainty with the depth and strength of the westerly flow in the afternoon hours. At this time, seabreezes are forecast to make it into KJFK and KLGA. Confidence is increasing for a late day seabreeze at KEWR (22Z-23Z).

OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY

Thursday: VFR.

Friday: VFR during the day.

Friday Night-Saturday: MVFR or lower in showers. An isolated thunderstorm possible Saturday. SW gusts 15-20 kt, becoming W-NW in the afternoon/evening.

Sunday: VFR. N gusts 15-20 kt possible.

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

MARINE
With high pressure nearby sub advisory conditions will prevail through Friday with ocean seas not much above 2 ft throughout. By late Friday a southerly flow increases with gusts potentially approaching 20 kt for some of the southern coastal waters.

The next chance for SCA conditions will be on the ocean waters Friday night into Saturday night with a frontal system moving across the waters. Winds and seas subside heading into Sunday morning, remaining below SCA criteria into the beginning of next week.

HYDROLOGY
At this time there are no hydrologic concerns through early next week.

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