textproduct: New York

SYNOPSIS

A cold front will pass through overnight, followed by high pressure building from the west today. The high will retreat offshore tonight as low pressure develops over the southern states. A secondary coastal low forms along the Mid Atlantic coast early Tuesday, passing south and east of Long Island Tuesday afternoon and evening. High pressure largely prevails for the second half of the week with the exception of a cold frontal passage on Thursday. Another low pressure system may impact the area next weekend.

NEAR TERM /UNTIL 6 AM THIS MORNING/

A high overcast remains across Long Island and SE CT. Mostly clear skies NW of there will spread east overnight.

Winds have switched to more of a W direction and will gradually veer to WNW, then more to the NW toward daybreak. Low temps in the lower/mid 30s by daybreak are close to normal.

SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/

Key Points:

* Winter Storm Watch in effect for Orange County on Tuesday as coastal storm brings an accumulating snow to portions of the interior, and mainly rain at the coast.

High pressure builds in from the west through this evening with diminishing NW winds and clear skies. Highs will top out in the upper 30s/lower 40s.

The focus then shifts to a winter storm that is likely to bring part of the area its first accumulating snowfall of the season. Southern branch shortwave energy tracking across the central Plains and into the Mid Mississippi Valley today will link up with low pressure over Gulf of Mexico. The latter of which tracks NE across the Southeast tonight and then begins to deepen more quickly along the Mid Atlantic coast Tuesday morning. The deepening coastal low will take a track to the south and east of Long Island Tuesday afternoon and evening, passing in close vicinity to the 40N/70W benchmark. The 30/12Z ECMWF continued to track to the southeast of the benchmark as does the EPS and GEFS. The other 30/12Z operationals, NAM12 and Canadian are still inside to the NW with warmer solutions. However, solutions are converging and even though the ECMWF is farthest SE, there is quite a bit of troughing to the NE of the low track. Subtle shifts in the low track will be critical to vertical temperature profiles and how far inland the rain/snow line gets. Differences in the low track seem to be hinging on the interaction with a northern branch shortwave dropping across the Midwest and Great Lakes during this time.The system is progressive with no blocking over the north Atlantic, which is the same reason high pressure quickly retreats away from the Northeast along with the cold air supply. Thus, the airmass is only marginally cold enough for inland locations to receive a snowfall with coastal locations likely to be all rain (possible mix at the onset).

Precipitation will develop from west to east Tuesday morning with coastal locations possibly seeing a brief mix. Rain/snow line will lift northwest across the interior with the only locations expected to be mainly snow will be north and west of I-84 in Orange County NY. This of course can change with even subtle shifts in track. Coastal locations will see little if any accumulation, with as much as 4-7 inches possible across Orange County NY, especially the higher elevations. This area has been placed under a Winter Storm Watch for Tuesday. Some locations in the inland transition zone could see 2-5 inches, which is advisory level. However, confidence is too low at this time for the issuance of an advisory. Liquid equivalent amounts come to just under an inch well northwest across upper portions of the Lower Hudson Valley to as much as an 1.5 inches across far eastern Long Island.

NBM probabilities have increased to around 50 percent for meeting warning criteria (6+ inches) across western Passaic, Orange, and Putnam counties. For advisory level (3-5 inches), there is 50-70 percent probability for Northern Fairfield CT, central/northern Putnam and Westchester NY, and western Passaic NJ.

Surface temperatures will also be marginal with highs in the lower/mid 30s inland. However, in the watch area where snowfall rates of 1-2 inches/hour are possible, snow will be able to cover roadways. Coastal locations will get up into the 40s. Refreezing of any standing water is likely Tuesday night as much of the area drops below freezing.

LONG TERM /WEDNESDAY THROUGH SUNDAY/

Key Points:

* High temperatures will run 10+ degrees below normal.

* A cold front moving through on Thursday will bring in a frigid air mass for Thursday night into Friday.

* Another low pressure system may impact the area next weekend.

High pressure builds in behind the departing low on Wednesday and will be followed by a cold frontal passage on Thursday. This is expected to be a dry frontal passage. A cold air mass then builds in and could bring lows as low as the single digits to parts of the interior.

Next weekend there is potential for another system to impact the area, but at this time there is too much uncertainty for specifics on rain/snow and stuck close to the NBM during that period.

OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY

Late tonight: Mainly VFR. Low chance of MVFR ceilings just before daybreak.

Tuesday: MVFR in rain along the coast, IFR/LIFR NW in snow, with a transition zone of rain/snow NW of the NYC metro terminals expected in the morning. Widespread IFR/LIFR late morning into the afternoon with rain, moderate to briefly heavy at times. LIFR/VLIFR in snow at KSWF through the afternoon. Conditions slowly improving to VFR during the evening from west to east as precipitation ends. Winds SE-E G15-20kt, becoming N by late day with G15-25kt, highest at the coastal terminals.

Wednesday: VFR. NW winds G15-20kt

Thursday: VFR. W winds G20-30kt.

Friday: VFR.

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

MARINE

SCA conditions both ahead of and following a cold frontal passage will produce SCA conditions into the early morning for far eastern Long Island Sound and the eastern/south shore bays of Long Island, and through the morning on the ocean. Winds and seas will lower as high pressure builds in the west today.

Winds and seas increase through the day on Tuesday with the passage of an offshore low pressure system. SCA wind gusts are likely on the ocean waters by the afternoon, and by the evening for the non-ocean waters. There may also be a brief period Tuesday night with gusts reaching gale criteria. Additionally, current wind forecast has seas reaching 5-9 ft for the ocean waters. It is worth noting that there is some uncertainty given the nature of the system. A small change in forecast track of the offshore low could cause a larger change in forecast winds than usual.

The system pulls away on Wednesday and winds and seas gradually lower. SCA seas may linger on the ocean waters through the day Wednesday. The next shot at SCA criteria will be with a cold frontal passage on Thursday and then again next weekend with another area of low pressure potentially impacting the area.

HYDROLOGY

Much of the area should not have problems with the potential of 1-2 inches of liquid equivalent on Tuesday. Minor nuisance and poor drainage flooding is possible, especially with snow melt and clogged drains.

OKX WATCHES/WARNINGS/ADVISORIES

CT...None. NY...Winter Storm Watch from late tonight through Tuesday evening for NYZ067. NJ...None. MARINE...Small Craft Advisory until 1 AM EST early this morning for ANZ332-340-345. Small Craft Advisory until 11 AM EST this morning for ANZ350- 353-355.