Marine Weather and Tide Forecast for Ossining, NY

KEY MESSAGES
1) The remnants of Isaias impact the area Sunday into Monday.

2) Showers possible late Tuesday into Wednesday with a chance of a thunderstorm as well.

DISCUSSION

KEY MESSAGE 1
No major changes to the fcst regarding the remnants of Isaias.

The system will bring PWATS of around 2 inches to the area, and with the deep lift exhibited in model time heights, bands of locally heavy rain along with embedded tstms are expected.
Timing is Sun, primarily in the afternoon, and Sun night. Some residual light rain or shwrs early Mon clearing out after noon per the latest guidance.

Based on the setup, would expect 1-2 inches of rain with locally higher amounts. This supports a mainly minor urban and poor drainage flood threat. WPC has made essentially no change to the excessive rainfall outlook, keeping the same area in Marginal indicating an isold flash flood threat.

The pres gradient is modeled to not be very strong with the system, so with BL wind barbs coming in around 30-35kt in both the GFS and NAM, would expect peak gusts generally around 35 mph, especially at the coast. There is the chance for embedded tstms however, so some locally higher gusts will be possible where storms are able to root in the BL. Best chances for this however are modeled to be over the ocean attm, but this could change with any slight change in the track.

With the increased onshore flow and fetch, high surf possible along the ocean as flow and swell direction is not much deviating from orthogonal to coastline.

There is a possibility of minor coastal flooding with this system as we come off a new moon, mainly for portions of the NYC Harbor, western South Shore Bays and western LI Sound for early Monday high tide cycles. To a lesser extent, early Tuesday high tide cycles could have minor coastal flooding as well, but this will be dependent on how fast winds lower and how much offshore flow there is.


KEY MESSAGE 2
Shortwave sharpens a passing longwave trough aloft late Tuesday into Wednesday. This will help push a cold front across the area probably sometime during Tuesday night/Wednesday morning, with chances for showers at that time. Low confidence at this time for potential impacts being that this is 5-6 days away, but models show enough CAPE (albeit mainly elevated) for a chance of thunder, and shear profiles would support at least a chance of strong gusts should there be enough CAPE.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
High pressure in control through tonight. Low pressure will approach Sunday morning.

VFR through tonight. Conditions lower to MVFR Sunday morning with -RA.

Winds become NE under 10 kt this morning and shift to the E then SE by the afternoon and early evening hours. There is a chance of sea breeze development for coastal terminals. Right now, best chances are for KGON and KBDR. E winds increase to around 10 kt Sunday morning.

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

Winds during the afternoon may be a bit more S than what is in the TAF should a sea breeze develop. The higher chance of this is at KJFK.

Timing of MVFR cigs and vsby may be off a couple of hours Sunday morning.

OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY

Sunday: Rain developing through the morning with MVFR/IFR likely by the afternoon and evening. Increasing E/SE winds 10-15g25kt afternoon and evening at the coast.

Monday: Showers and MVFR or lower ending early, becoming VFR late morning into the afternoon.

Tuesday: Mainly VFR. Chance of afternoon/evening showers.
Isolated thunderstorm possible.

Wednesday: VFR. 20kt N/NW gusts possible in the morning.

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

MARINE
Winds and seas will remain blw SCA lvls into Sun mrng. Winds and seas then build during the day Sun into Sun ngt. A SCA has been issued for the ocean where seas are modeled to increase to around 9 ft. Although winds may hit SCA lvls elsewhere, confidence is too low attm to issue the advy.

There is still a chance for the outer waters to hit gale, but this appears marginal attm so only kept the potential in the HWO implying a 30 percent probability.

The SCA may need to be extended thru Mon on the ocean with seas slowly subsiding, then all areas should stay blw SCA lvls on Tue. A cold frontal passage may result in SCA conditions Tue night and Wed, then winds and seas blw SCA criteria on Thu.

OKX WATCHES/WARNINGS/ADVISORIES
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from noon Sunday to 6 AM EDT Monday for ANZ350-353-355.