Marine Weather and Tide Forecast for Woodmont, CT

KEY MESSAGES
1) A slow moving low pressure system will bring multiple rounds of heavy showers and thunderstorms to the area today through Wednesday. A Flood Watch remains in effect for most of the area, with the potential for life threatening flash flooding.

2) There is a high risk of rip currents today and Wednesday.
(See Marine section below for discussion)

3) Potential for minor coastal flooding mid to late week with a coastal low.

DISCUSSION

KEY MESSAGE 1
A shortwave within the mean upper level trough dives down towards the area today. This becomes closed off and sits over the area through Thursday. The associated surface low deepens as it approaches today and occludes, also lingering nearby the area through Thursday. This is a highly anomalous summertime pattern with much of the guidance showing a sub 1000mb low. It is noted in WPC's Day 2 Excessive Rainfall Discussion that the 500-850mb heights fall below the 1st percentile according to NAEFS by 00z Wednesday. The combination of large scale lift and PWATs peaking around 2 inches is setting the stage for a significant rainfall event. The WPC maintains a moderate risk (level 3/4)
for portions of the area.

The 7/28 00z CAMs have trended slower with the onset of the heaviest showers and thunderstorms. Have adjusted the Flood Watch timing to account for this as noted in the What Has Changed section above. Additionally, have expanded the Flood Watch to include western Suffolk County and Middlesex County.

Forecast rainfall totals have not changed all that much. The 7/28 00z HRRR had a slight northward shift, with more of a focus on the Lower Hudson Valley. Back to back runs have now shown the heaviest totals being in this area. In general, an average of 3 to 5 inches is expected for portions of northeast NJ, the Lower Hudson Valley and southwestern CT. Isolated higher amounts are expected, with the latest HRRR PMM showing a max of 7+ in the Lower Hudson Valley. For the rest of the area, an average of 2 to 3 inches is forecast, with isolated higher amounts possible. The CAMs also continue to show peak hourly rainfall rates up to 2 to 3 inches per hour. This is also focused more on the Lower Hudson Valley, but can not be ruled out anywhere in the area.

The heavy showers and thunderstorms look to move in from the west in south to north oriented bands later today. They then pivot eastward overnight as the surface low settles. Location of the heaviest rain late tonight into Wednesday will largely depend on strength and location of the surface low. There is still some spread seen in the guidance with this. For example, the 7/28 06z HRRR is showing the low displaced well offshore, which is a big change from the 00z. This is a trend worth monitoring and would mean less activity through the day on Wednesday.

As the activity moves in from the west today, there is potential for some thunderstorms to become severe, mainly for portions of northeast NJ and NYC. This is shown in SPC's latest Day 1 Convective Outlook. Shear remains very weak, but decent instability (MLCAPE values between 1000 and 2000 J/kg) could allow for an isolate damaging wind threat with some collapsing storms. The tornado threat has been shifted farther to our south. The severe threat lowers overnight tonight.

Given yesterday's rainfall, there is some concern for river flooding. While current river forecast points are not expected to go into flood and widespread river flooding is not expected, it will have to monitored through the day.

KEY MESSAGE 2
See Marine section for details on rip current risk.

KEY MESSAGE 3
With the approach of a full moon midweek and an onshore E/SE flow with low pressure passing close by, minor coastal flooding is a possibility. There is still a fair amount of uncertainty at this time. Latest forecast brings some of the south shore back bay locations of LI and western LI Sound to just below minor coastal flood benchmarks during the evening/nighttime high tide cycles.

AVIATION /12Z TUESDAY THROUGH SATURDAY/
IFR to VFR conditions across the terminals this morning. IFR in the city terminals should improve to VFR by early to mid morning, while coastal terminals may only improve to MVFR. MVFR to IFR, and even LIFR is possible again overnight tonight. The lower conditions may be brief and associated with heavy rain accompanying thunderstorms.

Any precipitation should hold off until after 15Z (and possibly later). Otherwise, isolated to scattered showers and thunderstorms develop late this morning into the early afternoon, before a more widespread area of convection gradually works east over the terminals late afternoon into the evening.
Any thunderstorm could produce wind gusts above 40 kt. The showers likely persist into Tuesday night.

Generally, S/SE under 10 kt through tonight. S/SE gusts around 15-20 kt develop into this afternoon into the evening.

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

Timing of SHRA/TSRA onsets could be off by a couple of hours, possibly occurring a few hours later than forecast. Any thunderstorm could produce wind gusts above 40 kt and large hail.

Amendments likely for changing flight categories.

OUTLOOK FOR 012Z WEDNESDAY THROUGH SATURDAY

Wednesday: Mostly MVFR improving to VFR by the afternoon likely with showers. Thunderstorms and brief MVFR or lower possible.

Thursday: MVFR or lower possible. Showers possible and a slight chance of a thunderstorm. N-NW wind G15-20kt.

Friday: Mainly VFR, chance of an afternoon shower or tstm.

Saturday: Mainly VFR.

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

MARINE
A S/SE flow increases today. A Small Craft Advisory is in effect for all waters. The flow peaks tonight with 25 to 30 kt gusts. Ocean seas are expected to build to 5 to 6 feet. By Wednesday afternoon, sub SCA conditions are expected.

Sub SCA conditions likely then continue through early next week.

Rip Currents...

The rip current risk today has been upgraded to high. While the morning may start off more moderate, a strengthening S/SE flow and building swell are expected to bring a high risk by the afternoon.
Both local guidance and RCMOS show this.

The high rip current risk continues Wednesday morning and then may lower to moderate by the afternoon. While winds will be weakening, there will be a lingering S/SE swell around 4 to 5 ft at 7s.

OKX WATCHES/WARNINGS/ADVISORIES
CT...Flood Watch from 2 PM EDT this afternoon through Wednesday evening for CTZ005>007-009>011.
NY...Flood Watch from 2 PM EDT this afternoon through Wednesday evening for NYZ078-080-177-179.
Flood Watch through Wednesday evening for NYZ067>075-176-178.
High Risk for Rip Currents through this evening for NYZ075-080-081- 178-179.
NJ...Flood Watch through Wednesday evening for NJZ002-004-006- 103>108.
MARINE...Small Craft Advisory from 6 PM this evening to 2 PM EDT Wednesday for ANZ331-332-340.
Small Craft Advisory from noon today to 6 AM EDT Wednesday for ANZ335-338-345-355.
Small Craft Advisory from 6 PM this evening to 3 PM EDT Wednesday for ANZ350.
Small Craft Advisory from noon today to 2 PM EDT Wednesday for ANZ353.