textproduct: New York

SYNOPSIS

Low pressure moves eastward within Quebec as high pressure remains well southwest of the local region through today. Low pressure passes through the Canadian Maritimes tonight with high pressure building in from the south and west. This high pressure area moves across Saturday and then moves offshore for the rest of the weekend. Another frontal system approaches from the Great Lakes for Sunday. Warm front passes on Sunday with a cold front following that for Sunday night. High pressure returns thereafter for Monday before exiting and giving way to a developing wave of low pressure Tuesday into Tuesday night. Weak high pressure moves in for midweek.

NEAR TERM /THROUGH TONIGHT/

An area of low pressure will traverse Southern Quebec from west to east today while maintaining nearly the same central low pressure. Meanwhile, high pressure well south and west of the region will slightly fill in, a slight increase in central pressure. The result will still be a tight pressure gradient across the region but will trend weaker towards end of the day and into tonight.

Some mid level disturbances as diagnosed from positive vorticity maxima and some increases in low to mid level omega in addition to some elevated CAPE have necessitated an increase to the POPs in the forecast. A well mixed boundary layer and drier air moving in will be a limiting factor but after viewing several different CAMs did increase 10 to 15 percent with POPs. The highest increase in POPs was north and west of NYC, closer to the greater dynamics with more forcing for lift. With any wet bulb cooling, the primary precipitation type will be snow showers. POPs are mostly slight chance for this and in the time period of greatest daytime heating, this afternoon. This will be at a time when the coldest air at 850mb moves across the area along with the lowest 1000-500mb thickness as well. Forecast high temperatures stay mainly in the lower 40s, around 5 to 6 degrees below normal for this time of year. Air will still feel colder than the actual temperature with wind chills only in the low to mid 30s at most.

Regarding wind gusts, the forecast has lowered a small amount compared to previously forecast. Latest BUFKIT sounding show more 40kt for top of mixed layer gusts so appears the max or peak wind gust will be 45 mph, with most gusts in the 35 to 40 mph range. This will be under wind advisory thresholds which start at 46 mph and go through 57 mph. If there is a max wind gust of 46 mph, it appears it will be localized to where any moderate or heavy shower occurs and enhanced via downward momentum transfer. Otherwise, expecting most wind gusts to be under 45 mph.

For this evening, the low pressure will be moving farther northeast into the Canadian Maritimes with simultaneous closer approach of high pressure to the local region. The pressure gradient will decrease more and with this relaxation, winds will decrease more. This will really be observed late at night when the center of the approaching high pressure area will be getting into the Mid- Atlantic. With weakening lapse rates and main forcing getting displaced more north and east of the local area, any leftover snow shower activity will diminish in the evening. Clouds are expected to decrease but with enough winds and thereby mixing to prevent ideal radiational cooling. Forecast lows for tonight will exhibit less spatial range, ranging from the upper 20s to lower 30s for much of the region.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/

The short term forecast period will cover this weekend. Mid level pattern starts with ridging but eventually transition to more troughing to close out the weekend. At the surface, high pressure continues to build in from the south and west. Eventually the center of this high pressure area traverses the local area Saturday evening before exiting to the northeast late at night.

Another frontal system approaches from the Great Lakes Saturday night. Its associated warm front moves in by early Sunday and moves across later that same day. The local region becomes briefly within the warm sector as a cold front develops and approaches from the west. This cold front moves across from west to east Sunday night.

Dry conditions are expected for Saturday but with decreasing winds as vertical mixing will not be as deep, the airmass will not modify much in terms of temperature. Forecast high temperatures are pretty similar to those of the previous day and are mainly in the lower 40s Likewise, lows Saturday night will not deviate significantly from the lows the previous night, still ranging mainly from the upper 20s to mid 30s.

More warm air advection is expected for Sunday with more return SW flow developing. Rain showers back in the forecast for Sunday into Sunday night, likely afternoon into evening. At the onset, a wintry mix is forecast north of west of NYC. No significant accumulations are expected, as this looks to be a mainly rain event.

LONG TERM /MONDAY THROUGH THURSDAY/

Key Points:

* Monday should be mainly dry and colder as high pressure builds in from the west. Below normal temperatures are expected through Thursday.

* Low pressure may bring the first bout of winter weather to the area Tuesday into Tuesday night. There remains uncertainty in the low track, which will be critical in determining precipitation type.

NBM closely followed during this timeframe.

Global models are in good agreement with a shot of colder air Sunday night into Monday. However, an active southern branch of the polar jet will send Pac energy quickly across the country Sunday into Tuesday, which interacts with low pressure over the Gulf coast states. The latter tracks across the Southeast and into the Mid Atlantic states Monday night into Tuesday with the potential for secondary coastal low development. The low then passes to the south and east of LI Tuesday night. The exact track will be critical to precipitation type with only a marginally cold airmass in place. The latest 12Z GFS and ECMWF take the low close to the 40N...70W benchmark Tuesday night. This is a track that often is more favorable for snowfall and/or wintry weather across the forecast area. However, with no blocking over the north Atlantic, surface high pressure quickly lifts out to the Northeast ahead of the low. This will allow the cold air to erode over the region and allow more of a maritime influence. Right now, latest forecast calls for a snow/rain mix at the coast transitioning to all rain, and snow to a rain/snow mix inland. Ultimately, it will come down to how quickly the cold air departs and the exact track of the low passing to the southeast. Point being, it is too early to be specific with any details, but does bear watching.

High pressure then follows for Wednesday into Thursday with below normal temperatures.

OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY

Saturday: VFR. NW flow with gusts 15-20 kt.

Sunday: VFR in the morning then MVFR or lower with rain during the afternoon and at night. S flow with gusts 15-20 kt.

Monday: VFR. Slight chance of showers in the morning.

Tuesday: MVFR. Chance of rain/snow.

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

MARINE

The gale warning remains in effect for all waters until 6PM EST this evening. NY Harbor gale warning ends at 6PM EST this evening while the rest of the waters have their gale warning continuing until midnight tonight. Thereafter, would expect mostly SCA range wind gusts on the waters late tonight into early Saturday morning. Seas will eventually trend to less than SCA thresholds Saturday. A period of sub-SCA conditions for all waters follows until Sunday and Sunday night with SCA conditions returning to most of the forecast waters for wind gusts and ocean seas return to SCA levels.

High pressure will then follow for Monday with sub-SCA conditions. A coastal low could bring a return to SCA conditions on Tuesday.

HYDROLOGY

No hydrologic concerns through the middle of next week.

OKX WATCHES/WARNINGS/ADVISORIES

CT...None. NY...None. NJ...None. MARINE...Gale Warning until midnight EST tonight for ANZ331-332-335-340- 345-350-353-355. Gale Warning until 6 PM EST this evening for ANZ338.