Marine Weather and Tide Forecast for Mastic Beach, NY

NEAR TERM /UNTIL 6 PM THIS EVENING/
The forecast is on track. Showers are moving in from the west across the Lower Hudson Valley and northern New Jersey in association with approaching low pressure from the west.

A warm front to the south will slowly move northward today, stalling over the region by mid to late this morning. At the same time, an upper level trough dives south from the western Great Lakes region and aids in some intensification of this low over the Northeast.
Most of the deterministic models show the low intensifying as it rounds the base of the trough and heads into northern New England. A period of light rain showers is therefore in the forecast today through tonight. Much of the rain will generally be limited to northeast NJ, the Lower Hudson Valley, and southern CT as the stalled front bisects the area. Slightly more stable air to the south of the warm front will mean less in the way of showers until the cold front approaches and moves through tonight. In fact, some models show mainly dry conditions for NYC and much of Long Island today through tonight, so it's quite possible that some areas remain dry. There is also a brief period window for the possibility of thunder for the first half of Sunday night as instability aloft increases to a couple hundred J/kg, so continue to carry a slight chance for thunder from 2 am to 8 am Sunday night into Monday morning.

There continues to be a bit of a temperature gradient across the forecast area today, with area north and west of NYC seeing highs in the lower 60s, while the city and coastal areas see highs in the upper 60s to middle 70s. This is because the frontal boundary is expected to be within the forecast area today. However, there is a large spread in temperatures seen in the NBM for today (as much as 11 degrees in some cases) as there is uncertainty in where the frontal boundary will be. If it ends up farther north than is currently forecast, then temperatures will likely be warmer than what is currently in the forecast. If it remains to the south, then cooler temperatures can be expected.

SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/
A slight chance for showers Monday morning with a cutoff low over the Northeast providing some weak lift and some steep lapse rates noted in the forecast soundings in the lowest levels of the atmosphere, but much of any showers will occur north of the area, closer to the cutoff low. As the low treks farther northeast, chances for showers fall, so dry conditions expected everywhere by Monday afternoon.

Highs on Monday will be seasonable, ranging from the upper 50s inland, to the upper 60s along the coast. With the strengthening low pressure to the north and the high building in, a strong pressure gradient will set up over the area, and breezy conditions are expected, with gusts of 20 to 30 mph.

Continued cold advection through Tuesday as the upper low spins over northern New England and southeastern Canada will mean even cooler temperatures for Tuesday. Highs are not expected to climb above the 50s, with overnight lows Monday night into Tuesday in the middle to upper 30s away from the coast, and in the lower to middle 40s along the coast. Winds remain above 5 kt at night, so this will preclude the formation of frost.

LONG TERM /WEDNESDAY THROUGH SATURDAY/
A slow moving, positively tilted upper trough will linger over the region on Wednesday, then start to pull away on Thursday. This will induce sfc cyclogenesis well offshore, and also prevent high pressure to the west from building in too quickly. Once the trough pulls away and heights rise aloft, the high to the west should build in more strongly and settle over the area later this week.

This pattern will usher in the coolest air mass of the season, with well below normal temperatures on Wednesday (highs only in the 50s)
and then gradually moderating daytime temps after that under mostly clear skies. With that plus fairly light winds, most nights will radiate well, with lows in the 30s inland and 40s coastal/metro areas, and frost inland especially Wed night and Thu night.

AVIATION /12Z SUNDAY THROUGH THURSDAY/
A warm front will approach from the south. This will bring in bkn VFR cigs which may linger for much of the day especially inland, and there could be a few showers early this morning and again this afternoon near KSWF, then late today into this evening throughout.

E-NE winds less than 10 kt should become SE 5-10 kt at the metros by afternoon, then S around 10 kt late, with some uncertainty whether gusts up to 20 kt will materialize when winds become S. LLWS likely at the metros as SW winds increase to 40-45 kt at FL020.

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

No unscheduled AMD expected.

OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY...

Monday: VFR with any showers ending in the morning. NW winds 10-15G20kt in the morning, becoming W-NW 15-20 kt with gusts 25-30kt in the afternoon, then NW 10-15G20kt by late eve.

Tuesday and Wednesday: VFR. W-NW winds 10-15G20-25kt.

Thursday: VFR.

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

MARINE
With an increasing southerly flow behind the warm front and an increased pressure gradient as the low approaches and tracks across the region Sunday night and northeast Monday, wind gusts and ocean seas are expected to reach SCA levels by midday today. Also, the southerly wind gusts across the south shore Long Island bays will be near 25 kt. Gusts diminish on the back bays by around midnight or just after midnight Monday and SCA is in effect until 2 am Monday morning.

With a strong and gusty northwest flow developing Monday behind the cold front and low, small craft gusts are likely across all the forecast waters, therefore issued SCA for all waters from mid morning Monday through 11 pm Monday night. Ocean waters will continue to see wave heights above 5 ft through at least 2 am Tuesday, so extended the SCA for the ocean waters until then.

Quiet for Wed and Thu as high pressure slowly builds eastward toward the waters and the pressure gradient gradually relaxes.

HYDROLOGY
There are no hydrologic concerns through the start of next weekend.

OKX WATCHES/WARNINGS/ADVISORIES
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory from 11 AM to 11 PM EDT Monday for ANZ331- 332-335-338-340-345.
Small Craft Advisory from noon today to 2 AM EDT Monday for ANZ345.
Small Craft Advisory from noon today to 2 AM EDT Tuesday for ANZ350-353-355.