Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 261556 AFDOKX Area Forecast Discussion National Weather Service New York NY 1156 AM EDT Wed Apr 26 2017 .SYNOPSIS... Weakening low pressure near the Delmarva this morning tracks very slowly northeast today, passing southeast of Long Island tonight. The low dissipates along the New England coast on Thursday. A weakening cold front will approach from the northwest Thursday and Thursday night, then also dissipates over the area on Friday. Another cold front pushes south of the area Saturday night. This front then moves back toward the area as a warm front Sunday night into Monday with the associated cold front moving through Monday night into Tuesday morning. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Main area of moderate rain showers across parts of Southern CT into the Western Lower Hudson Valley with otherwise light rain showers across other parts of the region. There is some patchy fog mainly across Southeast CT and Eastern Long Island, which is locally dense this morning. Temperatures and dewpoints are pretty much right on track. A closed upper low near the Delmarva this morning will lift slowly NE today, in tandem with the surface low. This will keep the area under a weak NE flow. Weak lift and saturated low levels will result in light rain and/or drizzle for much of the day. In addition, with the diminishing NE flow and saturated low-levels, there will be some patchy fog. Highs today will be near normal in the lower 60s. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... Weakening low pressure passes to the south and east of Long Island tonight and dissipates along the New England coast on Thursday. Low-levels will remain moist with light NE winds. Widespread fog and drizzle is forecast tonight. The fog may even become dense overnight before gradually lifting on Thursday. With a subsidence inversion on Thursday and the development of a weak return SE flow, low clouds are likely to persist through the day. Overnight lows tonight will be mild in the lower to mid 50s, with highs a bit warmer on Thursday, in the 60s to around 70. The warmest readings will be across the interior Thursday. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... A surface cold front will approach the area Thursday night and weaken as it does so. Although there does seem to be some lift and instability in association with the front, it is not impressive and only a slight chance of showers and a passing thunderstorm is possible. Bermuda type high pressure will set up over the north central Atlantic. This will bring in some warmth and humidity to the area. Temperatures away from the coast will reach the upper 70s to lower 80s, while temperatures near the coast will remain in the lower to middle 70s, with perhaps some upper 60s along the immediate coast. Dew points will rise into the upper 50s to perhaps some lower 60s. The next cold front approaches from the northwest Saturday and pushes south of the area late in the day. This front looks to be a bit stronger than the previous one, with some lift noted in the middle and upper levels, but again, nothing too impressive. Most unstable CAPE values however are in the 1000-2500 J/kg range, mainly away from the coast, where conditions will be warmest. Lifted index values of -3 to -5 noted in the 00Z GFS. So, showers and a passing thunderstorm is once again possible Saturday. If further model runs continue with these values, some strong to severe storms are possible, but its too early right now. High pressure builds in for Saturday night and Sunday, with the cold front settling to our south. The front will then move back north as a warm front Sunday night into Monday, with a return to unsettled conditions starting Sunday. The warm front lifts north on Monday, with the cold front quickly approaching and moving through Monday night into Tuesday. && .AVIATION /16Z WEDNESDAY THROUGH SUNDAY/... Low pressure approx 50 miles SSE KJFK will meander in the vicinity before slowly shifting east this afternoon and evening. Mostly IFR expected, however some prevailing or tempo MVFR cigs expected mainly west of the Hudson River. SHRA becomes less likely this afternoon. NE winds around 10 KT becoming a little lighter this aftn. Winds eventually bcmg light and variable this evening. 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: CHC cigs tempo 1000-1500 FT or prevailing a couple hours this afternoon. KLGA TAF Comments: CHC cigs tempo 1000-1500 FT or prevailing a couple hours this afternoon. KEWR TAF Comments: Timing of beginning/end of MVFR cigs may be off by an hour or two. The afternoon KEWR haze potential forecast is YELLOW...which implies slant range visibility 4-6SM outside of cloud. KTEB TAF Comments: Timing of beginning/end of MVFR cigs may be off by an hour or two. KHPN TAF Comments: Timing of beginning/end of MVFR cigs may be off by an hour or two, or MVFR might be only tempo or not happen at all. KISP TAF Comments: Slight improvement in cigs might not occur or at least may be off by an hour or two this afternoon. .OUTLOOK FOR 12Z THURSDAY THROUGH SATURDAY... .Thursday...IFR/LIFR potential to start...with gradual improvement to VFR. .Friday...Chance of MVFR in showers/thunderstorms. .Saturday...VFR. && .MARINE... Dense fog has developed across the eastern waters this morning. This could potentially linger into the remainder of the day and spread westward. SCA for hazardous seas remains up on the ocean waters through Thursday night due to an easterly swell as weakening low pressure slowly lifts NE from the Delmarva this morning to the New England coast on Thursday. Waves remain above SCA criteria through Friday and much of Friday night. Waves remain below 5 ft through Sunday night, though there may be a brief period of 5 ft waves on the ocean as south to southwesterly flow builds ahead of an approaching cold front. Better chances of seeing SCA criteria on the ocean and back bays Monday into Monday night as a stronger frontal system impacts the region. Waves on the ocean build to 5 ft Monday, and up to 8 ft by Monday night. Gusts of 25 to 30 kt are possible for the ocean and back bays Monday into Monday night, diminishing late Monday night. && .HYDROLOGY... An additional tenth to quarter inch is possible across eastern LI/SE CT this morning. No significant rainfall expected in the long term. However, there may be isolated brief heavy downpours in any thunderstorms that develop during this time period. && .TIDES/COASTAL FLOODING... 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. Only 1/3 to 3/4 of a foot of surge is needed for minor flooding. A coastal flood statement has been issued for this evening`s high tide cycle for these locations. In addition, the elevated water levels combined with a prolonged period of 5-9 ft breaking surf tonight into Thu will result in beach erosion issues and may cause some localized dune toe erosion during the high tides. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory for hazardous seas until 6 AM EDT Friday for ANZ350-353-355. Dense Fog Advisory until noon EDT today for ANZ330-340-350. && $$ SYNOPSIS...JP/DW NEAR TERM...JM/DW SHORT TERM...DW LONG TERM...JP AVIATION...JC/PW MARINE...JM/JP/DW HYDROLOGY...JP/DW TIDES/COASTAL FLOODING...

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