Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 281804 AFDOKX Area Forecast Discussion National Weather Service New York NY 204 PM EDT Tue Mar 28 2017 .SYNOPSIS... A stationary front front will remain to the south today. Low pressure will pass to the south tonight. High pressure will build in on Wednesday and Thursday, then pass east Thursday night. Low pressure approaching from the Central states will impact the region Thursday night into Saturday. High pressure will build in on Sunday and Monday. && .NEAR TERM /THROUGH TONIGHT/... Adjusted coverage of showers/tstms based on ongoing and upstream activity, which was fairly well represented in high-res guidance. Elevated instability is best correlated with 12Z NAM TT indices and indicates that a second round of showers/tstms after the first moving across Long Island, over southern NJ and SE PA, and located NE of the sfc low centered between Washington DC and Baltimore, should hold together and move into NYC metro and Long Island from late afternoon into the early evening as the low moves ENE toward or just south of the area, Fog limited attm mainly to the higher elevations and also in the valleys well NW of NYC per sfc obs. The models were in good agreement so a blend was used for temperatures through tonight. && .SHORT TERM /WEDNESDAY/... Dry weather with a northwesterly breeze. Despite a cooler airmass in place, temperatures will actually be warmer than Tuesday because of deep mixing. Mostly sunny skies are progged, although some fair weather convective clouds will be possible if they are able to overcome the subsidence. A blend of the guidance was used for temperatures. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... The extended period will feature a split flow across the continental United States with systems moving through active northern and southern streams. As a result, even through there are similarities in the longwave and overall solutions, the details of the forecast have become more uncertain, and inconsistencies from run to run have increased. Currently there is now little to no phasing of systems impacting the east, and in particular the region, Thursday night into Saturday, and yet another system Monday night into Tuesday. There are now more uncertainties as to the depth of the lows, timing, and tracks. For late Thursday night through Saturday night have long period of probabilities, and even likely probabilities from Friday into Saturday. This is likely too long a period however, with the uncertainties wanted to maintain some consistency with prior forecasts. Both the ECMWF and GFS have some lingering cold air across the northern portions of the CWA Thursday night before warm advection increases. So have kept a mix of snow and rain inland. Canadian high pressure builds in for late Saturday night into Monday, and possibly Tuesday if ridging remains as per the GFS. The ECMWF is quicker to weaken and shift the ridge off shore Tuesday. Have introduced a low chance of precipitation for Tuesday. && .AVIATION /18Z TUESDAY THROUGH SUNDAY/...
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A couple of fronts remains near the region through this evening. A cold front pushes across the region overnight. High pressure then builds into the region on Wednesday. IFR or less continues through at least 06z in low stratus, fog and periods of rain. Winds will generally be less than 10kt from the east-northeast. After 06Z, a cold front will push across the region, with winds becoming northerly, then northwesterly and increasing to 10-15kt by 12Z Wednesday. At this time, conditions will gradually improve to VFR with mostly clear skies for Wednesday. 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: Amendments likely for changing flight categories through this evening. Wind direction change may be off by an hour or two. KLGA TAF Comments: Amendments likely for changing flight categories through this evening. Wind direction change may be off by an hour or two. KEWR TAF Comments: Amendments likely for changing flight categories through this evening. Wind direction change may be off by an hour or two. KTEB TAF Comments: Amendments likely for changing flight categories through this evening. Wind direction change may be off by an hour or two. KHPN TAF Comments: Amendments likely for changing flight categories through this evening. Wind direction change may be off by an hour or two. KISP TAF Comments: Amendments likely for changing flight categories through this evening. Wind direction change may be off by an hour or two. .OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY... .Wednesday...VFR. N-NW gusts 15-20KT. .Thursday...VFR. .Friday...A wintry mix possible early north and west with IFR conditions possible before a change to rain, otherwise sub VFR conditions with rain elsewhere. .Friday night and Saturday...Chance of rain with MVFR or lower conditions. E winds G20-25KT at coastal terminals for Saturday. .Sunday...VFR
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&& .MARINE... Winds and seas will remain below advy levels through tonight, but could briefly come close on the ocean tonight as NE winds increase on the back side of departing low pressure. Patchy fog may limit visibilities to 1 NM or less at times into the first half of tonight, but it should no longer be widespread. Advy level winds are also possible on Wed, and are more likely on the ocean Wednesday night into Thursday, with strong and gusty northwest winds and seas approaching 5 ft, as high pressure builds in. Occasional gusts to 25 kt also possible Wed night on the eastern Sound and bays. The next chance of advy conditions will be late Friday through Saturday night as southerly winds increase ahead of low pressure. && .HYDROLOGY... Basin average rainfall of a half inch or less can be expected through tonight. Locally heavier amounts just over an inch plus local nuisance poor drainage flooding are possible with any heavier thunderstorms. Additional rainfall of 1/2 inch to 1 inch is possible Thursday night through Saturday. No hydrologic concerns are anticipated. && .TIDES/COASTAL FLOODING... Astronomical tides remain high due to a recent new moon. Water levels may approach minor flood thresholds during the high tide cycles Thursday night, with minor flooding possible Friday night as a low pressure system approaches. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...12/MET NEAR TERM...12/Goodman/MET SHORT TERM...12 LONG TERM...MET AVIATION...BC MARINE...12/Goodman/MET HYDROLOGY...12/MET TIDES/COASTAL FLOODING...

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