Area Forecast Discussion
Issued by NWS Upton, NY

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090 FXUS61 KOKX 232337 AFDOKX Area Forecast Discussion National Weather Service New York NY 737 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/...
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A severe tstm watch has been issued for nern NJ until 10pm with a primary threat of damaging winds. Made minor update to temps and dewpoints to reflect current observations. Otherwise, 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. There is more instability this evening with less overnight. 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 lowered coverage of thunderstorms overnight to isolated in forecast overnight. 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.
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&& .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 using GMOS with slight adjustments. 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 moderate risk of rip currents is forecast for Saturday. && .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 /00Z SATURDAY THROUGH WEDNESDAY/...
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A cold front approaches this evening, then slowly moves through the terminals by around 12 to 16Z tomorrow morning. Initial area of thunderstorms will gradually decrease in intensity as they approach the western-most terminals this evening - including the NYC metro area. Additional showers and thunderstorms are expected overnight with the approach of the cold front, with heavy rain and reduced visibility possible at times. Winds for most of the night will be from the south-southwest with occasional gusts to around 20 kt possible. A low level jet will move up the coast, with a brief period of LLWS possible primarily at LGA/JFK/ISP and to a lesser extent elsewhere. Following the front tomorrow morning, winds will shift to west- northwest with increasing gusts through the day and decreasing cloud cover. 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 for showers and thunderstorms. Wind gusts may be stronger than forecast for tomorrow. KLGA TAF Comments: Amendments possible for showers and thunderstorms. Wind gusts may be stronger than forecast for tomorrow. KEWR TAF Comments: Amendments possible for showers and thunderstorms. Wind gusts may be stronger than forecast for tomorrow. KTEB TAF Comments: Amendments possible for showers and thunderstorms. Wind gusts may be stronger than forecast for tomorrow. KHPN TAF Comments: Amendments possible for showers and thunderstorms. Wind gusts may be stronger than forecast for tomorrow. KISP TAF Comments: Amendments possible for showers and thunderstorms. Low chance of IFR conditions developing overnight. Wind gusts may be stronger than forecast for tomorrow. .OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY... .Saturday night-Sunday Night...VFR. Gusty WNW flow diminishing in the evening. .Monday-Tuesday...VFR. A chance of shra/tsra Monday afternoon into Tuesday. .Wednesday...VFR.
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&& .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 with residual higher seas. 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. Total rain expected is 0.5 to 1 inch with locally higher amounts. 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...JMC/JM SHORT TERM...JM LONG TERM...Fig AVIATION...MD MARINE...Fig/JM HYDROLOGY...Fig/JM TIDES/COASTAL FLOODING... EQUIPMENT...

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