Area Forecast Discussion
Issued by NWS Upton, NY

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245 FXUS61 KOKX 270901 CCA AFDOKX Area Forecast Discussion...CORRECTED National Weather Service New York NY 401 AM EST Mon Feb 27 2017 .SYNOPSIS...
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High pressure centered south of Long Island will continue to drift out to sea today. A warm front will lift north of the area on Tuesday. A cold front approaches on Wednesday, then crosses the area Wednesday night. This returns cold, but seasonable weather for the end of the week, with the chance for light snow for early Friday. It`s a dry weekend and warming up on Sunday.
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&& .NEAR TERM /THROUGH TONIGHT/... Clear skies this morning will give way to rapidly increasing mid and high clouds today. Based on satellite, the leading edge over southwestern Pennsylvania gets here around 12-13Z, with the thickest stuff over the Ohio Valley arriving by noon. It should be an overcast afternoon as a result. Subsidence today weakens by 00Z with some weak lift developing thereafter. At this point however the deepest moisture will be exiting, so the forecast has been kept dry right through tonight. Temperatures will rebound quickly as the inversion breaks this morning. The Pine Barrens on Long Island could be the big winner, where temperatures in the teens should shoot up around 20 degrees in a matter of minutes as the inversion mixes out. The guidance was in good agreement and reasonable based on temperatures aloft and southwesterly flow, so a blend was used through the period. && .SHORT TERM /TUESDAY/... The main question is whether it actually rains. The models continue to back off, as they are just not supplying any moisture to the region. With the Gulf of Mexico opening up, there is a concern the models are not pumping enough moisture into the flow. As a result, chances for precipitation have been essentially been kept the same, with high chances by the end of the day. With regard to temperatures, it will be mild again with southerly flow. This temperature structure is likely to result in enhanced sea breeze flow particularly across southern portions of Queens and Nassau counties, as well as Brooklyn. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
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NWP appears fairly clustered and consistent with the overall pattern, but not without lots of local forecast problems this week. 1. Tuesday - Wednesday. WAA advection pattern will likely bring light RA by late AFTN TUE there persists on and off into WED AFTN. We have likely POPs, but expect these to go to categorical as timing of PCPN becomes clearer. There`s lots of spread in the temperature guidance for Tuesday and have gone with the cooler side (GFS) due to the onset of PCPN and the extensive cloud cover. That being said, Temps should get well into the 60s by WED away from the coast - of course with a strong gradient at the coast. Advection fog also becomes a forecast problem and can see repeat of a few days ago. 2. Wednesday AFTN/EVE. Instability is once again present along with very strong shear in excess of 60 KT. LI`s of -2 C and Total Totals in the lower 50s are not to be ignored this time of year as we saw Saturday night. Thus have included TS in the forecast. No enhanced wording, but that may come as we get closer. 3. Thursday. Windy with steady or slowly falling temps. Think 40 mph should do it for the winds, but we could get close to wind advisory criteria. 4. Friday. Clipper system passes the region. Looking at the GEFS suggest much of the energy passes across up State and across New England. Thus, keeping just a 30 POP for light snow. The operation GFS is on the higher end of the QPF across the OKX Forecast area. On the other hand, the Operational ECMWF is south of the area. Temps are FCST slight below normal for Saturday, but rebound to the lower 50s for Sunday.
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&& .AVIATION /09Z MONDAY THROUGH FRIDAY/... VFR through the TAF period as high pressure off the Mid Atlantic coast moves east. High confidence in SW flow less than 10 kt and increasing to 10-15G20KT by late morning and into the afternoon. ...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: Start time of gusts may be off by +/- 2 hours. KLGA TAF Comments: Start time of gusts may be off by +/- 2 hours. KEWR TAF Comments: Start time of gusts may be off by +/- 2 hours. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: Start time of gusts may be off by +/- 2 hours. KHPN TAF Comments: Start time of gusts may be off by +/- 2 hours. KISP TAF Comments: Start time of gusts may be off by +/- 2 hours. .OUTLOOK FOR 09Z TUESDAY THROUGH FRIDAY... .Late Monday night...VFR. .Tuesday...Chance of light rain/MVFR conds. .Tuesday night-Wednesday morning...Areas of fog with light rain continuing. MVFR/IFR and possibly lower. LLWS possible with SW winds 45-55 kt at 2kft. SW winds G15-20KT Wednesday morning. .Wednesday afternoon-Wednesday night...Showers and a chance of thunderstorms. MVFR or lower possible. SW winds G20-30KT. Winds become westerly late Wednesday night. .Thursday...VFR. W-WNW winds G20-25KT. .Friday...MVFR/IFR possible with a chance of light snow. WNW winds G20KT. && .MARINE...
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Southwest winds will produce Small Craft Advisory conditions on the eastern two thirds of the ocean today and tonight. Elsewhere, winds and waves are expected to remain just below criteria at this time. For Tuesday, light flow will allow seas on the ocean to remain below 5 feet. The region will be in between the high pressure well offshore and a low pressure area moving into the Midwest. The pressure gradient gradually tightens through midweek with a strong cold front eventually approaching from the west. The resulting increasing SW flow will build seas to SCA range beginning Tuesday night and continuing through midweek. Ahead and just behind the cold front will be potentially the highest of winds, when gales will be possible for the eastern waters and the ocean Wednesday through Wednesday evening with otherwise SCA winds for all waters. After this cold front moves across Wednesday night, there will be gusty NW flow and cold air advection. The ocean will likely remain at SCA levels through the rest of the marine forecast period through Friday. SCA level winds will persist Wednesday night through Thursday and come to a brief lull below SCA Thursday night before returning to around SCA levels Friday.
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&& .HYDROLOGY...
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Rainfall from Tuesday afternoon through Wednesday night should run from 0.5 to 0.75 inches, with locally higher amounts possible. Release from spring snow melt is occurring down the Connecticut and Housatonic Rivers.
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&& .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 6 AM EST Tuesday for ANZ350-353. && $$ SYNOPSIS...12/Tongue NEAR TERM...12 SHORT TERM...12 LONG TERM...Tongue AVIATION...JE MARINE...12/JM HYDROLOGY...12/Maloit

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