textproduct: New York

SYNOPSIS

A coastal low pressure system passes southeast of the region today and tonight, and into the Canadian Maritimes by Wednesday. High pressure then returns for Wednesday and Thursday, with a cold frontal passage Thursday afternoon. Low pressure will then pass to the south and east Friday night into Saturday, with weak high pressure returning Saturday night into Sunday, followed by another cold front Sunday night.

NEAR TERM /THROUGH TONIGHT/

What's Changed: No significant changes to the forecast. Onset of precipitation delayed by a few hours.

Key Points:

*Winter Weather Advisories remain in effect until 10pm for Orange, Putnam, Rockland and Western Passaic Counties today.

*Coastal storm will bring an accumulating snow to interior portions of the local Tri-State, mainly north and west of I-287 in NJ and NY, and I-84/I-684 in S CT. After a brief start as wet snow or a rain/snow mix, plain rain for NYC and coastal areas.

High pressure continues to move offshore this morning with light winds. Current surface analysis showing most of the area has been able to radiatively cool to at or below freezing but is beginning to warm slowly under light easterly flow, with upper 20s across the interior and coastal CT, with low to mid 30s NYC and LI. Back to the west, sfc analysis and radar places precipitation shield associated with the eventual coastal low complex across eastern WV and eastern VA in the form of rain and mixed precipitation as of 06Z. Radar also shows some returns as far east as Central PA this hour, though only some scattered light snow being reported given the mid level dry air still in place across much of the east.

All this said, expecting the surface low, and attendant precipitation to head northeastward over the next several hours, and model guidance continues to be in good agreement with this. Precipitation looks to have a difficult time starting here initially given the dry air still in place per 00Z KOKX sounding, with model soundings not showing good saturation until around, or after 15Z. So given all this, thinking any precipitation may not start locally until the 12- 15Z timeframe from west to east, with the bulk of precip falling in the 15-00Z timeframe across the area. A wet snow may mix in briefly across NYC, LI and coastal CT this morning, though accumulations are not likely here.

The low deepens as it traverses northeast, and ends up southeast of Long Island this afternoon, and there is good model agreement on this. However, the ptype forecast evolution continues to be a challenge. Given the later precip start which should allow additional time for PBL warming, and less overall QPF, think the changeover may be quicker and the rain/snow line pushes further inland this afternoon. So have opted to maintain all snow across Orange County for much of the event, though areas south of there will likely transition by early afternoon, with NYC, Long Island and coastal CT remaining all cold rain. So any accumulations of a very wet snow across the forecast area have to occur on the early side of the system (save for Orange County) before the eventual changeover to rain. In addition, as the low departs this evening, some wet snow may mix in across especially across the interior.

Temperatures should rise to above freezing for all but Orange County by early afternoon, the upper 30s/lower 40s for NYC/NJ metro, and as high as the upper 40s. Winds pick up in wake of the departing low this afternoon/tonight, with NW winds 15-25 gusting up to 35 mph. The combo of snow load and winds could result in a few downed tree branches/power outages mainly across Orange County this afternoon/tonight. Refreezing of any standing water is likely tonight as much of the area drops below freezing.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/

Key Points:

*Dry conditions for the period.

*High temperatures in the upper 30s and low 40s, which is about 10 degrees below normal.

For Wednesday, high pressure over the OH Valley moves slowly east, with the local area caught between it and the departing coastal system. The pressure gradient looks to relax by midday Wed, so any lingering gusts should subside. Thursday looks similar as the high remains to our southwest and a cold front approaches from the northwest. It looks to pass through the area Thursday afternoon dry and with little fanfare, other than some increased cloudiness.

LONG TERM /FRIDAY THROUGH MONDAY/

Key Points:

* Below normal temperatures expected through the period, running as much as 10-15 degrees below normal Friday and again Sunday night/Monday.

* Low pressure passing to the south may give a glancing blow late Friday night into Saturday.

Very cold on Friday as a 1030 mb high (supported via strong mid level confluence behind the departing upper trough over eastern Canada) slides across, with highs from the upper 20s well inland to mid 30s metro/coastal sections. The high will retreat Fri night, with a srn stream low passing to the south in progressive quasi- zonal flow aloft. Polar jet may be modeled too strongly and ridging off the SE coast too weakly, so think the sys will at least give a glancing blow late Fri night into early Sat afternoon, with 30 PoP for all but the lower Hudson Valley. Thermal profiles supportive of light snow late Fri night/early Sat morning, then a transition to a light rain/snow mix for interior SE CT and all rain across ern Long Island and coastal SE CT for late morning/early afternoon.

Cold frontal passage Sunday night as a closed low swings across ern Canada will usher in yet another very cold air mass for early next week, with lows in the teens/20s and highs in the upper 20s/lower 30s for Monday. This shot of cold air looks to be longer lasting than the one for Thu night/Fri of this week.

OUTLOOK FOR 06Z WEDNESDAY NIGHT THROUGH SATURDAY

Late tonight: Becoming VFR. Wednesday: VFR. NW winds G15-20kt before 15Z.

Thursday: VFR. W winds G20-25kt in the afternoon/evening.

Friday: VFR.

Friday night: Chance of MVFR in light snow late.

Saturday: Chance of MVFR in light snow/rain, mainly in the morning and mainly E of the NYC metros.

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

HYDROLOGY

Minor nuisance/poor drainage flooding is possible with 0.5-1.5 inches of precipitation likely, especially with snowmelt and any clogged drains with fallen leaves. Rainfall rates however are not expected to exceed 0.5"/hr. This would be for a period from mid morning to Tuesday evening. Otherwise, there are no significant hydrologic concerns expected through next weekend.

OKX WATCHES/WARNINGS/ADVISORIES

CT...None. NY...Winter Weather Advisory until 10 PM EST this evening for NYZ067>069. NJ...Winter Weather Advisory until 10 PM EST this evening for NJZ002. MARINE...Small Craft Advisory from 1 PM this afternoon to 10 AM EST Wednesday for ANZ331-332-335-338-340-345. Small Craft Advisory from 7 AM this morning to 1 PM EST Wednesday for ANZ350-353-355.