Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 232009 AFDOKX Area Forecast Discussion National Weather Service New York NY 409 PM EDT Fri Jun 23 2017 .SYNOPSIS... A cold front will slowly approach tonight, eventually moving across Saturday morning into Saturday afternoon. A secondary cold front moves across Saturday night. High pressure builds to our southwest Sunday into Monday. A weak cold front will move through our area later Monday. High pressure builds towards the Mid Atlantic coast Tuesday and Wednesday, before moving offshore Thursday. Unsettled weather return for the end of the week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... The main forecast concern tonight into early Saturday will be the heavy rain associated with any showers and thunderstorms ahead of an approaching cold front. More details on this in the hydrology section but there will essentially be a low chance of flooding because of the heavy rain potential. This is from the remnant low of Cindy that will be traveling along the cold front and this moves in by early Saturday. Elevated instability as diagnosed from Showalter indices only slightly negative so have isolated thunderstorm wording in forecast. Shear further increases with low level jet tonight as SW winds increase to 45-55 kt between 3 and 4 kft, so any thunderstorm that develops could be strong with gusty winds with a marginal threat that thunderstorms could be severe. Lows tonight were a blend of NAM12/GMOS and adjusted slightly higher. Overall, temperatures will not drop much from this evening through the night. Boundary layer moistens overnight with patchy fog developing, especially in areas that are outside the rain showers. The moderate risk of rip current development continues through this afternoon, due to building southerly winds waves and a 2 ft long period SE swell. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Starting out Saturday morning, the remnant low of Cindy with the showers and thunderstorms will be near to just southwest of the region. Heavy rain threat remains early in the morning with patchy fog early especially in areas outside of rain showers. It moves south of Long Island Saturday afternoon as the cold front moves across. The showers and thunderstorms move offshore in the afternoon as winds become more westerly. Depending on how fast clouds decrease, the surface temperatures could warm up quickly. Expecting an above normal day regarding temperatures with boundary layer mixing giving highs mid to upper 80s most places with some lower 90s in Northeast NJ. For Saturday night, a secondary cold front moves across which will result in winds becoming more northerly late Saturday night after its passage. Dry conditions, light winds and continued mostly clear conditions will result in radiational cooling. A vast range of lows will be seen in the region from upper 50s in rural inland sections to lower 70s in parts of NYC from the MET guidance. A high risk of rip current is likely Saturday with building southerly swells and wind waves. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Dry conditions expected on Sunday as a ridge of high pressure builds towards the Mid Atlantic coast. Expect high temperatures to be in the low to mid 80s on Sunday. A weak surface cold front will affect the local area Monday afternoon into Tuesday. The system will not have a great deal of moisture associated with it, but cooler temperatures aloft may spark off a shower or t-storm late Monday into early Tuesday. High temperatures on Monday and Tuesday are expected to be in the mid to upper 70s to lower 80s. High pressure continues to build towards the area on Wednesday and slowly moves offshore on Friday. A few showers are possible Friday afternoon. Temperatures will start out in the upper 70s to near 80 on Wednesday then slowly increase to mid to upper 80s by Friday. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... Low pressure tracks through eastern Canada this afternoon into Saturday morning with an associated cold front approaching this evening and moving through the terminals 12Z to 16Z Saturday. Winds will be generally from the southwest 220 true, with gusts to around 20 kt. Sea breeze influence will keep the winds more southerly along the coastal areas this afternoon. With the passage of the cold front winds shift to west to northwest, to the left of 310 true, and become gusty Saturday morning. Generally VFR with occasional MVFR ceilings this afternoon. Restrictions in fog and showers develops after 06Z, isolated to scattered thunder is possible late this afternoon and this evening. Another round of showers develops late tonight with the chance of heavy rain and IFR visibilities. 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 possible late this afternoon and this evening for developing thunderstorms. KLGA TAF Comments: Amendments possible late this afternoon and this evening for developing thunderstorms. KEWR TAF Comments: Amendments possible late this afternoon and this evening for developing thunderstorms. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility greater than 6SM outside of cloud. KTEB TAF Comments: Amendments possible late this afternoon and this evening for developing thunderstorms. KHPN TAF Comments: Amendments possible late this afternoon and this evening for developing thunderstorms. KISP TAF Comments: Amendments possible late this afternoon and this evening for developing thunderstorms. The chance of thunder is less likely east of the NYC terminals. .OUTLOOK FOR 18Z SATURDAY THROUGH WEDNESDAY... .Saturday...VFR. WNW winds gusting around 20 kt. .Saturday night-Sunday Night...VFR. .Monday-Tuesday...VFR. A chance of shra/tsra Monday afternoon into Tuesday. .Wednesday...VFR. && .MARINE... Conditions on the waters are becoming more rough. Sub SCA winds on non-ocean waters are expected through Saturday night. Ocean stays in SCA through much of Saturday night. Less SCA winds Saturday night with an overall weak pressure gradient. Conditions across the area waters are expected to remain below small craft advisory levels Sunday through the middle of the week. && .HYDROLOGY... The potential for minor urban and poor drainage flooding with localized possible flash flooding will remain with the showers and thunderstorms forecast through early Saturday. The precipitable waters increase to near 2.3 to 2.4 inches early Saturday with tropical moisture from the remnants of Cindy getting entrained along the front. There is a threat for flash flooding late tonight through Saturday morning from a likely complex of showers and thunderstorm associated with a frontal wave (remnants of Cindy) moving through the areas. Uncertainty exists on the exact track of this wave...which could be from the Northern Mid- Atlantic to Southern New England. There are no hydrologic impacts expected Sunday and through the end of the week. && .TIDES/COASTAL FLOODING... Astronomical tides are running very high, especially during the evening high tide cycles tonight and Saturday. Less than 1 ft of surge is needed during these evening high tide cycles for minor flooding, and in some cases less then 1/2 ft. The expected S/SW flow is not favorable for surge, but a background anomaly will likely be enough for minor coastal flooding of the most vulnerable coastal locales along the south shore bays of Western Long Island, along Jamaica Bay, and along western Long Island Sound during this time. && .EQUIPMENT... KOKX weather radar is scheduled for maintenance starting today June 23rd for a period of 3 days. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 2 AM EDT Sunday for ANZ355. Small Craft Advisory until 6 AM EDT Sunday for ANZ350-353. && $$ SYNOPSIS...Fig/JM NEAR TERM...JM SHORT TERM...JM LONG TERM...Fig AVIATION...MET MARINE...Fig/JM HYDROLOGY...Fig/JM TIDES/COASTAL FLOODING... EQUIPMENT...

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