Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 280307 AFDOKX Area Forecast Discussion National Weather Service New York NY 1107 PM EDT Thu Apr 27 2017 .SYNOPSIS... A series of weak fronts cross the region Friday through Sunday. A more significant cold front will pass through from the west Monday night, followed by weak high pressure into Wednesday. Another weak frontal system may begin to approach on Thursday. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... 1030 PM Update - Dense fog over central Suffolk on Long Island, but that`s is as of now. Will hold off on a Dense Fog Advisory despite the very moist south southeast flow. The lack of fog at KFOK makes me think that the fog will not become widespread along with the modified Richardson`s number suggesting more stratus. As for PCPN, latest HiRes NWP is not supporting much and have thus dropped POPs to 20. Activity over VA is weakening as well. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... The cold front washes out across the region Friday. The more SW flow continues as the airmass will continue to get warmer. Ridging aloft occurs. Fog burns off in the morning. More sun is expected. Highs Friday in the upper 60s out east where rain showers and low clouds could linger to lower 80s for western locations where there will be more sun. A chance of showers and thunderstorms early but drier conditions move in the afternoon with more of a westerly component to wind. Next system approaches Friday night from the NW. Ridging will make it more difficult for thunder. Showers chances increase late at night into early Saturday. Lows in the low 50s to low 60s Friday night. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Forecast for this time frame remains rather consistent. First, a weakening front nearby and a passing mid level shortwave may generate some showers and possibly an elevated tstm mainly inland Sat morning. Then Bermuda type high pressure setting up over the western Atlantic will set up a favorable flow for warm temperatures on Sat, even across coastal areas, as winds shift to the southwest and then west. Have continued to trend warmer, with some places in NE NJ reaching the upper 80s, on the higher end of guidance. If the slightly warmer NAM were to verify, with full mixing to 850 mb and late day downslope flow, Newark could make a run at the first 90- degree reading of the year. Many places away from south facing shorelines should get into at least the lower 80s, with 70s along the coastlines and in the hither elevations inland. Capping inversion will keep afternoon precip at bay. A back door cold front dropping from the north should come through at night, with some showers and possibly an elevated tstm, as low levels stabilize but mid and upper levels remain marginally unstable. It will be noticeably cooler for Sunday with near average temps in the 60s. Not much change for the long term with a warm front approaching Sunday night and lifting through on Monday, accompanied by showers and possibly an elevated tstm. Temps on Mon will be above average, with upper 60s across Long Island and most of southern CT, and 70s from NYC north/west. Some showers could come in late day ahead of an approaching cold front, but the main push should come at night, with only slight chance for a tstm as instability looks rather marginal. Any remaining showers out east on Tue should end by late morning, with fair wx and temps once again slightly above average for both Tue and Wed as weak high pressure slides south, with upper 60s and lower 70s. Increasing clouds on Wed ahead of the next weak frontal system should limit high temps on Thu to the lower and mid 60s. && .AVIATION /02Z THURSDAY THROUGH TUESDAY/... A weakening cold front approaches from the west tonight and moves into the NYC area around 12Z Friday. The front moves slowly east of the NYC terminals and dissipates Friday morning. High pressure over the western Atlantic builds toward the southeast coast Friday morning. IFR/LIFR should remain through the night. Winds shifting from SE to SW between 07z and 10z could improve conds slightly...but should still remain IFR until at least 12z at the metro terminals. Conditions then gradually improve W-E although exact timing of the cold front and dissipation remains uncertain. SHRA/TSTMS approaching from the S and W have been weakening as they move towards the area. Thus will keep any mention of pcpn out of the TAFs. E-SE winds becoming S-SW late at the metro terminals and light and variable elsewhere. Winds shift to west with the passage of the cold front then come back around to southwest as the front dissipates. Sea breezes are likely Friday afternoon. .OUTLOOK FOR 00Z SATURDAY THROUGH TUESDAY... .Friday night-Sunday...VFR. There is a chance of isolated thunderstorms north and west of the metro terminals Saturday morning into the afternoon. .Sunday night-Monday...MVFR to IFR with light rain and fog. .Monday night-Tuesday...MVFR with showers and isolated thunderstorms. Improving to VFR with a cold front passage Tuesday. && .MARINE... SCA for ocean seas goes through Friday. Otherwise, sub SCA for other waters. The SCA will be more marginal for ocean Friday night. Dense fog redevelops tonight on the waters and lasts until late Friday morning. Fairly high confidence in increasing S-SW flow pushing ocean seas above 5 ft by Mon afternoon ahead of a cold front, with gusts up to 25 kt and seas 5-8 ft Mon night. Ocean seas over 5 ft will likely linger into Tue. && .HYDROLOGY... No widespread hydrologic impacts foreseen through the next 7 days. && .TIDES/COASTAL FLOODING... High tide cycle is occurring now and will allow Advisory to expire at 03Z. Due to high astronomical tides and an easterly swell the next couple of days, water levels may approach minor coastal flood benchmarks, in particular across the south shore back bays of western LI during the evening high tide cycle. Only 1/3 to 3/4 of a foot of surge is needed for minor flooding. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Dense Fog Advisory until 10 AM EDT Friday for ANZ330-335-338- 340-345-350-353-355. Small Craft Advisory for hazardous seas until 6 PM EDT Friday for ANZ350-353-355. && $$

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