Area Forecast Discussion
Issued by NWS Upton, NY

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KOKX 261141 AFDOKX Area Forecast Discussion National Weather Service New York NY 741 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/... As of 730 am, current radar shows a line of convective showers over the Twin Forks of Long Island and into Southern Connecticut. This band will head north over the next few hours. Therefore, have added a slight chance of moderate rain for these areas through 10 am. Otherwise, forecast is on track. A low-level easterly jet ahead of weakening low pressure over the Delmarva this morning will pass east before daybreak putting an end to the steadiest rain across eastern CT and Long Island. 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, especially this morning across CT and LI. 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 /08Z WEDNESDAY THROUGH SUNDAY/... Low pressure tracks slowly toward the area from the south today. Generally expect IFR ceilings today. Cannot rule out LIFR/VLIFR ceilings this morning. Visibilities should remain MVFR to IFR this morning. During the afternoon, visibilities likely improve to MVFR or even VFR for a short time before falling again by sunset. IFR, LIFR or even VLIFR ceilings and visibilities are forecast for this evening. Any moderate to heavy rain departs early this morning, with on and off light rain and drizzle continuing thereafter. Northeast winds begin to lighten this morning, and speeds of 10 kt or less are expected through much of the day today. Winds will be light and variable by 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: Amendments are possible for low ceilings and visibilities this morning. Timing for slight improvement may be off an hour or two this afternoon. KLGA TAF Comments: Amendments are possible for low ceilings and visibilities this morning. Timing for slight improvement may be off an hour or two this afternoon. KEWR TAF Comments: Amendments are possible for low ceilings and visibilities this morning. Timing for slight improvement may be off an hour or two this afternoon. The afternoon KEWR haze potential forecast is YELLOW...which implies slant range visibility 4-6SM outside of cloud. KTEB TAF Comments: Amendments are possible for low ceilings and visibilities this morning. Timing for slight improvement may be off an hour or two this afternoon. KHPN TAF Comments: Amendments are possible for low ceilings and visibilities this morning. Timing for slight improvement may be off an hour or two this afternoon. KISP TAF Comments: Amendments are possible for low ceilings and visibilities this morning. Timing for slight improvement may be off an hour or two this afternoon. .OUTLOOK FOR 06Z THURSDAY THROUGH SATURDAY... .Late tonight...Potential for LIFR/VLIFR in fog. .Thursday...IFR/LIFR potential to start...with gradual improvement to VFR. .Friday...Chance of MVFR in showers/thunderstorms. .Saturday...VFR. && .MARINE... 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. && $$ SYNOPSIS...JP/DW NEAR TERM...DW SHORT TERM...DW LONG TERM...JP AVIATION...PW MARINE...JP/DW HYDROLOGY...JP/DW TIDES/COASTAL FLOODING...DW

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.