Area Forecast Discussion
Issued by NWS Upton, NY

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312 FXUS61 KOKX 241635 AFDOKX Area Forecast Discussion National Weather Service New York NY 1135 AM EST Fri Feb 24 2017 .SYNOPSIS... High pressure will remain steady over the western Atlantic through tonight. A frontal system will approach on Saturday, and move across Saturday Night, followed by building high pressure Sunday into Monday. A couple of fast moving disturbances may bring unsettled conditions beginning Monday night. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... East coast ridging and western Atlantic high pressure control the region today, with mostly sunny skies. With region in warm sector, another early springlike day today, with highs in the 60 to lower 70s. A moist air mass advecting over cold ocean waters could lead to advection fog/stratus developing along the NJ coast and working northward toward the south shore of Long Island late. With SW flow aloft and plenty of sunshine, most areas from NYC north/west should reach the lower 70s. Elsewhere, temps away from south facing shores should climb well into the 60s. Marine influence will likely limit temps to the 50s for most of the south shore areas. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... East Coast ridging tonight will give way to a Central Plains upper low shearing toward Hudson Bay on Saturday, with associated trough and frontal system swinging toward the region late in the day and then though Sat night. Coastal stratus/fog development are favored in a second night of mild/moist southerly flow tonight. Models soundings and high- res/SREF guidance strongly indicating more widespread stratus/fog development across much of the region tonight, which may then linger across CT/Long much of the day with low level flow backing more to the S-SE. Temps will likely be cooler on Sat with more of an onshore flow and cloud cover, with temps ranging from well into the 60s for areas well NW and W of the Hudson, to 50s for south and east coastal areas. Not much in the way of forcing or focus for rain overnight into Sat morning, so shower threat looks isolated at most. Can`t rule our some patchy drizzle later tonight into Sat morning as well if low levels saturate sufficiently. Main rain activity will be along and immediately behind an approaching frontal system. A narrow band of convection will likely approach from PA/NY along the leading edge of the front late Sat into Sat eve, with strong convergence of a moist (PW 2-3 std above avg) and marginally unstable air mass advecting in via a 40-kt LLJ, plus lift via an approaching shortwave. There is potential for brief heavy rain/thunder/30-40 mph wind gusts with this line mainly west of the Hudson, where there should be some weak surface/elevated instability. This line should weaken as it encounters the stable marine layer along the coast. Otherwise, expect lighter post-frontal activity Sat eve ahead of approaching shortwave axis, shifting offshore by around midnight. In the wake of the shortwave/cold front Sat night, a dry and cooler air mass will build in on breezy NW flow. With strong CAA and deep mixing, wind gusts of 30-40 mph possible. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... High pressure builds towards the area on Sunday and Sunday night. Temperatures on Sunday will be in the low to mid 40s with low temperatures Sunday night in the low to mid 30s along the coast and upper 20s inland. High pressure moves offshore Monday, as a storm system moves out of the mid Atlantic states Monday night and Tuesday. A chance of rain and snow are possible with the storm system. Light rain is possible again on Tuesday night and into early Wednesday as a warm front pushes north of the region Wednesday, followed by a cold front later Wednesday. High Pressure builds behind the cold front on Thursday. Temperatures during this period should be 5 to 10 degrees above normal. && .AVIATION /16Z FRIDAY THROUGH TUESDAY/... Late spring-like pattern with a warm front north over central NY State and New England with convection along it. A cold front approaches from the west on Saturday. VFR today with a light south-southwest flow. The forecast question of the day is the development of Fog and Stratus this evening along the coast. Latest thinking is 00Z or later for this to occur. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/www.weather.gov/zny/n90 KJFK TAF Comments: Lots of uncertainty on development of fog and status this evening. Timing could be as early at 21Z, but more likely is around 00Z. KLGA TAF Comments: High confidence in VFR through the day. Uncertainty with development of fog and status late this evening. KEWR TAF Comments: High confidence in VFR through the day. Uncertainty with development of fog and status late this evening. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: High confidence in VFR through the day. KHPN TAF Comments: High confidence in VFR through the day. KISP TAF Comments: Lots of uncertainty on development of fog and status this evening. .OUTLOOK FOR 12Z SATURDAY THROUGH TUESDAY... .Saturday...Mainly IFR or lower in the morning before possibly improving to MVFR or VFR. .Saturday night...MVFR or lower likely with rain. .Sunday...VFR. .Monday...VFR. .Tuesday...Possible MVFR in showers. && .MARINE... Persistent S-SW flow around western Atlantic high pressure and long period easterly swells should have seas hovering around 3-4 ft much of tonight, and up to 5 ft Saturday morning. Will hold off of SCA due to marginal nature of hazard. Potential for dense fog over the near shore waters late today into Saturday morning, which may linger until a cold frontal passage Sat evening. Ocean seas should gradually build to SCA levels Saturday afternoon ahead of a cold front, with marginal SCA gusts possible. Higher confidence is in SCA gusts in the wake of frontal passage Sat Night, with even potential for a brief period of gale force gusts. SCA conditions expected to continue across the ocean waters on Sunday. Winds and waves will then gradually subside Sunday night into Monday as high pressure moves south of the area. The next chance of SCA conditions will be Monday night into Tuesday as winds strengthen following a warm frontal passage. Winds and seas may remain at or near SCA conditions through late week ahead of a cold front. && .HYDROLOGY... Basin avg rainfall of 1/4 to 1/2 inch is likely on Saturday, with local amounts up to an inch that could cause associated nuisance ponding. && .CLIMATE... The following are record high temperatures for today February 24, 2017 along with the forecast high temperature. Record High Temperature Forecast High ----------------------------- ------------- Central Park........75 (1985) 70 LaGuardia...........73 (1985) 71 Kennedy.............60 (1984) 65 Islip...............59 (2000) 65* (record broken earlier) Newark..............73 (1985) 71 Bridgeport..........60 (2016) 62 The following are record high minimum temperatures for Saturday February 25, 2017 along with the forecast minimum temperature. Record High Min Temperature Forecast Min ------------------------------ ------------ Central Park........51 (1930) 53 LaGuardia...........49 (1996) 54 Kennedy.............46 (1996) 50 Islip...............47 (1996) 50 Newark..............47 (1996) 54 Bridgeport..........44 (1996) 49 && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...Fig/NV NEAR TERM...Goodman/NV SHORT TERM...NV LONG TERM...Fig AVIATION...Tongue MARINE...Fig/Goodman/NV HYDROLOGY...Fig/NV CLIMATE...

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