Area Forecast Discussion

WHAT HAS CHANGED

Small craft advisories have been discontinued for the western and central ocean zones.

KEY MESSAGES

1) Quick moving low pressure passes to the north Tuesday into Wednesday.

2) Minor coastal flood benchmarks could be briefly reached along some vulnerable portions of the coastline during the Tuesday morning/early afternoon high tide cycle.

3) A strong frontal system could produce thunderstorms on Friday, then strong winds and much colder temperatures over the weekend.

DISCUSSION

.KEY MESSAGE 1...

As the low that impacted the area yesterday continues to move east, high pressure over SE Canada will try to nose in from the northeast into tomorrow, providing for a backdoor cold front that pushes into the area Tuesday morning. The cloud cover and cooler air associated with this airmass will keep temperatures over the easternmost areas cooler than the western areas where mostly sunny to partly cloudy conditions should persist under a lighter and more SE flow. Highs for the western CWA on Tuesday will be into the low to middle 70s with eastern locations likely not breaking out of the 60s.

The backdoor cold front likely halts its progression into the late morning as a progressive moving low pressure system slides to the north of the area. This will bring a more S/SE flow into much of the area through the afternoon. The low quickly moves north of the area with a cold front eventually moving through by late Wednesday. Much of the region should remain dry as the greatest forcing remains to the north, though a stray shower or thunderstorm isn't entirely ruled out, especially for the northern and eastern most tiers of the CWA.

.KEY MESSAGE 2...

Elevated water levels driven by a recent new moon and low pressure that passed through over the weekend may allow some coastal locations to briefly enter minor flood stage during Tuesday's late AM/early PM high tide cycle. Inundation up to a half foot is possible. Best chances of occurrence are along vulnerable spots in S Nassau and along portions of the western LI Sound in SW CT. Some of the eastern bays of LI may also approach minor flood benchmarks. A Coastal Flood Statement was issued for southern Nassau and southern Fairfield. Water levels then look to fall enough to preclude any further flooding beyond this cycle.

.KEY MESSAGE 3...

Global models have been consistently indicating a strong cold frontal passage for the end of the week.

The 12Z GFS, CMC, ECMWF, EC-AIFS, and the AI-GFS all have the timing of the front sometime between Friday afternoon and very early Saturday morning. There will be good shear with the system, however the amount of instability will depend on the timing of the front and any maritime cloud cover. As a result, confidence in strong to severe thunderstorms is low at this time. However, due to the setup, especially with a potential 170+ kt H3 jet over ON/QC, it will need to be watched.

Confidence is higher for strong winds and colder temperatures behind the fropa and into the weekend. Deep mixing on nwly flow could push winds to advy levels. In addition, some subfreezing temps will be possible as thicknesses plummet. For Sat night, the NBM has lows in the 30s for almost the entire area. The MEX however is even colder with widespread upr 20s despite the wind. Because the cold airmass appears to be highly transitory, did not stray from the NBM at this time.

AVIATION /03Z TUESDAY THROUGH SATURDAY/

There will be an approaching back door cold front late tonight into early Tuesday. This front stalls within the region briefly thereafter on Tuesday and then shifts back northeast as a warm front.

For NYC terminals and KSWF, a VFR TAF period is expected. For KHPN and to the east of NYC terminals, MVFR and in the case of KGON, even IFR ceilings are expected for some time on Tuesday with otherwise a VFR TAF period expected for those terminals. For all terminals, there is a possibility for MVFR to IFR fog late tonight into Tuesday morning but did not include in TAFs at the moment due to lower probability.

Winds for TAF period, NW flow initially becomes more variable direction tonight with wind speeds mainly less than 10 kts. NYC terminals will hold to near 10 kt winds this evening before diminishing late this evening into overnight. More southerly flow expected Tuesday with wind speeds near 7-10 kts, more easterly component east of NYC terminals.

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

Low probability of MVFR stratus early Tuesday and late in the TAF period.

OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY

Tuesday Night: MVFR possible with a brief rain shower, mainly east of NYC terminals. Occasional SW gusts 15-20 kt.

Wednesday: Mainly VFR. Westerly gusts 15-20 kt mainly during the day.

Thursday: Mainly VFR. Late at night, possible MVFR or lower with increasing likelihood of showers.

Friday: MVFR or lower with showers. S-SW wind gusts near 20-25 kt with some peak gusts near 30 kt. NW gusts near 30 kt at night.

Saturday: VFR. NW gusts near 25-35 kt.

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

MARINE

Winds will continue to diminish as low pressure tracks further away from the waters. The SCA has been discontinued for the western and central ocean waters as seas have fallen closer to 4 feet. The SCA is in effect for the eastern ocean thru tonight for lingering high seas at around 5 ft.

Winds and seas may hit SCA criteria on the ocean late Tue into Wed with a weak frontal system moving by. The remaining waters are expected to remain below SCA levels at this time.

A strong frontal system will then impact the waters Friday and Saturday. SCA conditions are likely on all waters for Friday, then NW gales are possible on all waters behind the system Friday night and into the weekend.

OKX WATCHES / WARNINGS / ADVISORIES

CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 6 AM EDT Tuesday for ANZ350.