Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 290549 AFDOKX Area Forecast Discussion National Weather Service New York NY 1249 AM EST Sat Feb 29 2020 .SYNOPSIS... Low pressure will gradually weaken over Canada through Saturday. High pressure over the area on Sunday gives way to a slow moving frontal system that will impact the area with multiple waves of low pressure through mid week. High pressure will then briefly follow for Thursday with a possible area of low pressure impacting the area next Friday. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Winds should abate late tonight, with gusts more occasional. There will be intervals of clouds, but generally a partly cloudy to mostly clear night is expected. Lows will generally be in the lower to mid 20s, except upper 20s NYC metro. This is a bit below normal. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/... Dry weather continues Sat and Sat ngt. Time heights suggest clouds developing in the 5000-6000 ft range. A weak cold front should pass in the late aftn, resulting in an increase in nwly winds. Moisture is limited with the front so no pcpn is expected attm. All models keep pcpn relegated to the higher elevations N and W of the fcst area. The NBM was used for temps both Sat and Sat ngt. Clouds are expected to decrease late Sat ngt, but winds again area expected to stay up at least a little. There is a narrow late ngt window for clearing and calm winds, and if this does occur, temps will be several degrees colder than fcst. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Warmer and wetter will be the theme as we head into next week with tons of uncertainty for the second half of the week. The upper low retreats east of the Canadian maritimes with both ridging aloft and at the surface building across the Northeast on Sunday. This will be short-lived though as a nearly zonal flow to start the week will send warmer Pac air into the region with temperatures rising to 10 to 15 degrees above normal by mid week. Global models start off in some resemblance of agreement as a frontal system works into the area Monday into Tuesday, but progresses slowly in response to a deepening northern branch upper trough over the upper Mississippi Valley. Several waves of low pressure will bring periods of showers, mainly from Tuesday night into Wednesday. How much rain is uncertain, due to the complexity of interaction between the two branches of the polar jet. The 12Z GFS takes the closed low over the northern Baja at the start of next week and phases it with the northern branch by mid week. This results in a stronger frontal system and deeper low developing across New England Wednesday into Wednesday. The GGEM and ECMWF never allow this phasing, sending a weaker system through the area Tuesday night into Wednesday morning. The southern branch closed low then lifts off to the NE with a variety of solutions as it precedes the next digging northern branch shortwave trough. Complex interactions such as wavelength separation will determine whether that low shoots off well to the south like the ECMWF, or is farther north on Thursday like the GGEM with a potential winter weather event. The GFS just takes that northern branch energy across the area Friday as a clipper low with some light snow. Bottom line, there are lots of solutions with low confidence for the second half of the week. Thus, will keep chances of precipitation low for the second half of the week. In fact, temperatures also will be problematic depending upon which solution verifies. A colder second half of the week is possible. One would think that the nature of the pattern this winter would lend credence to a more progressive pattern. However, there are no signs of a pattern change in the long term. Stay tuned. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... Low pressure centered over southeastern Canada gradually weakens overnight into Saturday afternoon as weak surface troughs move through the terminals. Meanwhile, high pressure will slowly build in from the west through Saturday night. VFR through the TAF period. Winds will be mainly west to northwest through the forecast, with slight varying direction as surface troughs move across the terminals. Overnight winds will be west 10 kt or less, with occasional gusts at the NYC metro terminals to around 20 kt. Winds and gusts increase Saturday morning to around 15 kt with gusts 20 to 25 kt, and then increase a few more knots during the afternoon as winds veer to NW. Northwest winds then diminish Saturday evening, with the gusts coming to an end. .OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY... .Late Saturday night...VFR. .Sunday...VFR. NW/W winds G15-20kt. .Monday...VFR expected. .Tuesday and Wednesday...MVFR or below with a chance of rain. && .MARINE... SCA conditions will remain on the ocean through at least Saturday and will likely need to be extended into part of Sunday. Elsewhere, marginal SCA conditions are possible. High pressure moves east of the waters Sunday night into Monday with an approaching frontal system through mid week with multiple waves of low pressure. An extended period of SCA conditions are forecast on the ocean waters in a SW flow from Monday night into Wednesday. Conditions are more marginal elsewhere. && .HYDROLOGY... No hydrologic impacts are expected thru the middle of next week. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO35 (162.55 MHz) is still operating at reduced power. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 6 PM EST this evening for ANZ350- 353-355. && $$ SYNOPSIS...DW NEAR TERM...DW/PW SHORT TERM... LONG TERM...DW AVIATION...JE MARINE...DW/PW HYDROLOGY...DW EQUIPMENT... is the U.S. government's official web portal to all federal, state and local government web resources and services.