Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 301748 AFDOKX Area Forecast Discussion National Weather Service New York NY 148 PM EDT Fri Sep 30 2016 .SYNOPSIS... The region will remain in between high pressure to the northeast and low pressure to the southwest through the weekend. The low then slowly exits to the east through Tuesday as high pressure builds into the north. This high then continues to build down into the region through the middle of next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Looking at latest radar trends and 12z GFS appears to be having a fairly decent handle on current precipitation. Based on these have lowered pops, especially over western zone, and also gone over to areal coverage wording for chance pops or lower and intermittent for categorical pops. Based on this, have also lowered pops slightly this afternoon a well. Refer to the hydrology section of the AFD for details. Generally a cool, damp afternoon with gusty NE winds, up to 35-40 mph near the coast. Highs should mainly be in the upper 50s-lower 60s. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/... Based on latest radar trends and 12z guidance, did lower pops and qpf this evening over mainly western zones. Remainder of forecast for tonight and Saturday was left unchanged. Chances for rain continue into the short term with the cut off low remaining to the west and the frontal boundary to our south. Again, models differ on exact placement of the heaviest rain. Refer to the hydrology section of the AFD for details. Winds diminish tonight as the pressure gradient relaxes somewhat over the region. Temperatures will be a bit warmer on Saturday, but still a bit below normal for this time of year, generally lower to middle 60s. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... No significant changes made to the long term period as a stagnant and unsettled weather pattern continues for the weekend and into early next week as a stacked cutoff low remains over the Ohio Valley as a ridge over the Western Atlantic remains in place. Models continue to show the upper ridge gradually weakening and shifting south enough early next week to allow the upper low to finally start moving northeast early next week. At the surface, stacked low pressure sits over the Ohio Valley, with a stationary front running northeast from the Mid Atlantic and southeast of Long Island through the weekend. A series of weak waves running along this front will produce periods of rain this weekend. Then as the stacked low finally begins to lift northeast early next week, expect the the main moisture/lift axis to also weaken and lift NE. Lingering scattered showers could continue through early next week via cold pool instability interacting with the maritime air mass. Thereafter, potential for deep layered ridging developing for mid week as the region lies under ridging of an omega blocked pattern. The dry ridged pattern may continue into late week, but will have to monitor the evolution of Hurricane Matthew. Please refer to the National Hurricane Center forecasts for further information. Temperatures will be at or slightly below normal on Sunday, then return to near seasonable for early next week. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... The terminals will remain between high pressure to the northeast and low pressure to the southwest through the weekend. Mainly MVFR conditions this afternoon and evening. Pockets of IFR visibilities are possible in -SHRA through this evening. Ceilings likely fall to IFR late this evening and overnight with a lower chance of -SHRA. Flight categories then improve to MVFR after 12z Saturday as -SHRA redeveloping. NE winds through the TAF period. Gusts 25-30 KT at city/coastal terminals and 20-25 KT at inland terminals. Strongest gusts expected through this evening before diminishing overnight. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/ KJFK TAF Comments: IFR visibilities possible at times in -SHRA. Gusts to 30 kt possible. Low chance for IFR ceilings after 22z. KLGA TAF Comments: Brief IFR ceilings through 19z. IFR visibilities possible at times in -SHRA. Gusts to 30 kt possible. KEWR TAF Comments: IFR visibilities possible at times in -SHRA. KTEB TAF Comments: Amendments for flight categories possible. Gusts may be more occasional than indicated. KHPN TAF Comments: Amendments for flight categories possible. Gusts may be more occasional than indicated. KISP TAF Comments: IFR visibilities possible at times in -SHRA. Gusts to 30 kt possible. .Outlook for 18Z Saturday through Wednesday... .Saturday afternoon...IFR/MVFR in rain. .Saturday Night-Sunday Night...MVFR or lower possible with showers. .Monday-Tuesday...Mainly VFR with isolated to scattered showers possible. .Wednesday...VFR. NE gusts 20-25 kt near the coast. && .MARINE... Minor changes were made with this update to reflect the latest trends in observations and guidance. The forecast appears on track. Gusts to gale force are expected into this evening on all but NY Harbor, where Small Craft Conditions are expected through tonight. SCA winds are also expected on the remainder of the waters through at least 10z Saturday as well. The strong winds will drive high seas, with seas ranging from 8-13 ft on the coastal ocean waters and from 5-7 ft on the Sound. SCA criteria should continue into mid Saturday morning for the ocean waters, while everywhere else, winds will come down below 25 kt around sun rise. Waves over the Sound will also come down below 5 ft by around sun rise on Saturday. Waves will diminish on the ocean waters as well, but they will remain at or above 5 ft through the day Saturday. Conditions fall below SCA levels Sat night into early Sunday as easterly flow weakens and seas subside. These sub-SCA conditions will remain likely for early next week under a weak pressure gradient. Seas on the ocean waters start to increase mid week with small craft conditions returning. && .HYDROLOGY... There is a high degree of uncertainty on the amount of rainfall through Saturday. Around 1-1 1/2 inches of QPF possible through Saturday night, with locally higher amounts possible. The prolonged nature of the rain event should preclude any hydrologic issues. No significant rainfall for early to middle portion of next week. && .TIDES/COASTAL FLOODING... Although wind fields weaken by the high tide this evening, widespread minor flooding continues to be a concern for the south shore of Long Island and thus a Coastal Flood Advisory remains in effect for this time frame for Southern Nassau County. Additionally, a persistent easterly sweep of 6 to 10 ft surf today will likely result in minor to moderate beach erosion issues at the the ocean beachfront. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...Coastal Flood Advisory from 6 PM to 10 PM EDT this evening for NYZ179. NJ...None. MARINE...Small Craft Advisory until 8 AM EDT Saturday for ANZ338. Gale Warning until 8 PM EDT this evening for ANZ330-335-340- 345-350-353-355. && $$ SYNOPSIS...BC/Maloit/JP NEAR TERM...Maloit SHORT TERM...Maloit/JP LONG TERM...BC AVIATION...DS MARINE...BC/Maloit/JP HYDROLOGY...BC/JP TIDES/COASTAL FLOODING... is the U.S. government's official web portal to all federal, state and local government web resources and services.