121 FXUS61 KOKX 111418 AFDOKX Area Forecast Discussion National Weather Service New York NY 1018 AM EDT Thu Oct 11 2018 .SYNOPSIS... Tropical moisture will surge northward from North Carolina and Virgina today, well in advance of a cold front over the Ohio Valley. The front will move across late tonight and pass offshore on Friday while the post-tropical remnant low of Michael passes southeast of Long Island. High pressure will build in this weekend, while an upper level disturbance moves across on Saturday. The high will pass east late Sunday into Monday, followed by a cold front Monday night, Please refer to National Hurricane Center products for further details on Michael. && .NEAR TERM /THROUGH TONIGHT/... Forecast on track this morning with just some minor adjustments to reflect latest observations. Bands of heavy showers will ride up the coast today, reaching the metro area by afternoon. Ingredients for flash flooding will be in place, namely anomalously high PW 2.25", tall/skinny CAPE, a deep warm cloud layer of 14kft more typical of late summer than of autumn, plus deep layer SW flow and short Corfidi vectors suggesting potential for training of cells. Thus the flash flood watch remains in effect for the entire CWA. Isolated severe wx will be another concern late this afternoon. MLCAPE increases to 500-1000 J/kg later today in NE NJ, NY and areas just north as sfc temps rise to 75-80 in those areas, and model fcst soundings indicate enough low level shear and 0-3km CAPE to make for some rotating storms that could produce brief damaging winds or an isolated tornado. By tonight, the heaviest rain should focus along a mid level baroclinic zone and upper level jet streak setting up just S of Long island, due in part to the approach of the sfc cold front, also due to the approach of what should be then post-tropical storm Michael moving off the Mid Atlantic coast. Rainfall of 1-2 inches is possible during that time across eastern Long Island, with lesser amounts of 1/2 to 1 inch for NYC, western Long Island, and coastal CT. The front should move through late tonight, with NW winds picking up in the NYC metro area just before daybreak. && .SHORT TERM /FRIDAY/... As the cold front moves farther offshore and as post-tropical storm Michael makes its closest approach, rain out east should come to an end in the morning. We should also see noticeably cooler/drier air moving in on brisk NW winds, gusting as high as 30-35 mph, possibly 40 mph for a time in the NYC metro area and across Long Island, and as high as 25-30 mph inland. Temps may rise only a few degrees from overnight lows, with highs remaining in the 60s. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... A rather progressive pattern for the long term period as a number of shortwaves rotate through a long wave trough in the upper levels. The first of these shortwaves will affect the area on Saturday, which will approach quickly from the west on the western side of a high pressure system centered over the mid-West. With only a weak surface reflection, rain amounts will be light. High pressure from the mid-West then builds in Saturday night and quickly pushes off the East Coast on Sunday. This will allow a cold front to approach from the west on Monday, pushing off the East Coast Monday night. There are some timing differences with the operational models. An area of low pressure may develop along this frontal boundary over the mid-Atlantic states, then ride the boundary, tracking northeast Monday night into Tuesday morning. This low is much deeper in the ECMWF than the GFS and completely lacking in the Canadian model. If the ECMWF is right, a quick moderate rain will impact the area late Monday night into Tuesday, with only light rain seen in the GFS. However, the GFS develops another more potent low Tuesday night and is more unsettled as another more significant trough over south central Canada becomes negatively tilted as it moves into the Northeast. As for temperatures, given a trough over the Eastern US for the long term, temperatures will be at or below normal for this time of year. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... An approaching frontal system will interact with tropical moisture to produce periods of hvy rain today and tngt. The system will track out to sea on Fri. Cigs varying mostly 700-1500 ft through this evening. Shra thru approx 19-20z, then less likely until evening, although an isolated TSTM cannot be ruled out even before this time period. Increase in shra coverage expected this evening ahead of a cold front that passes through around midnight, and iso TSTM still possible. S-SW winds 10-15kt with some gusts up to 20kt possible. Winds in the 40-45kt range about 2000 ft at KGON so LLWS included for this afternoon, although it is mrgnl. ...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 likely today. Exact height that cigs settle is a bit uncertain. The afternoon KJFK haze potential forecast is YELLOW...which implies slant range visibility 4-6SM outside of cloud. KLGA TAF Comments: Amendments likely today. Exact height that cigs settle is a bit uncertain. The afternoon KLGA haze potential forecast is YELLOW...which implies slant range visibility 4-6SM outside of cloud. KEWR TAF Comments: Amendments likely today. Exact height that cigs settle is a bit uncertain. The afternoon KEWR haze potential forecast is YELLOW...which implies slant range visibility 4-6SM outside of cloud. KTEB TAF Comments: Amendments likely today. Exact height that cigs settle is a bit uncertain. KHPN TAF Comments: Amendments likely today. Exact height that cigs settle is a bit uncertain, although IFR or lower is expected. KISP TAF Comments:Amendments likely today. Exact height that cigs settle is a bit uncertain, although IFR or lower is expected. .OUTLOOK FOR 12Z FRIDAY THROUGH MONDAY... .Friday...MVFR with a chance of -RA, mainly in the morning, then becoming VFR. Winds NW 15-20KT G25-30KT. Gusts to 35 kt possible mainly early. .Saturday-Sunday...Mainly VFR. A few showers possible Saturday into Saturday evening as well as Sunday night. .Monday...Chance of MVFR in showers. && .MARINE... SCA conds should develop this afternoon on the ocean and the eastern Sound/Bays. Ocean seas will build to 5 ft during this time. After a lull in conditions for part of tonight, winds and seas should increase quickly as a cold front moves through and as then post-tropical storm Michael passes SE. Gale warning in effect for the ocean waters as N-NW winds gust to 35-40 kt from about 8 AM through 2 PM. SCA in effect for all other waters daytime Fri for gusts up to0 30 kt, possibly also touching 35 kt briefly in NY Harbor and on the south shore bays. Ocean seas could reach 7-11 ft Fri afternoon. Ocean seas will quickly diminish Fri night, and by Saturday morning, all waters should be below 5 ft as the remnants of Michael track away from the waters. Thereafter, waves should remain below 5 ft as the flow will be predominantly NW. Wind gusts Friday night will start off 25-30 kt on the ocean waters, but will diminish and come below 25 kt around midnight or thereafter. Wind gusts of 25 kt on the ocean waters are possible on Tuesday as a potential area of low pressure impacts the waters. && .HYDROLOGY... Rain today into tonight may be heavy at times as a southerly LLJ transports a deep tropical moisture plume into the area ahead of a cold front. While total rainfall should range from 1.5-2 inches, localized amounts of 2-4 inches can not be ruled out. Flash Flood Watch remains in effect. && .TIDES/COASTAL FLOODING... Astronomical tides, running about 1 to locally 2 ft above normal, may result in minor coastal flooding around the times of high tide this morning into early afternoon. && .CLIMATE... The following are record high minimum temperatures for today, along with the 24-hour forecast lows prior to Midnight LST. SITE............RECORD/YEAR.....FCST Central Park....68/1949.........67 LaGuardia.......69/1990.........66 Kennedy.........67/1990.........68 Islip...........66/1990.........69 Newark..........69/1990.........68 Bridgeport......63/2011.........66 && .EQUIPMENT... NYC NOAA Weather Radio Station KWO35 (162.55 MHz) remains off the air for an extended period of time. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Flash Flood Watch through late tonight for CTZ005>012. NY...Flash Flood Watch through late tonight for NYZ067>075-078>081- 176>179. NJ...Flash Flood Watch through late tonight for NJZ002-004-006- 103>108. MARINE...Small Craft Advisory from 6 AM to 6 PM EDT Friday for ANZ330- 335-340-345. Small Craft Advisory from 2 PM this afternoon to 8 PM EDT this evening for ANZ330-340. Small Craft Advisory from 4 AM to 6 PM EDT Friday for ANZ338. Small Craft Advisory until 6 AM EDT Friday for ANZ350-353-355. Gale Warning from 6 AM to 6 PM EDT Friday for ANZ350-353-355. && $$ SYNOPSIS...Goodman/JP NEAR TERM...BC/Goodman SHORT TERM...Goodman LONG TERM...JP AVIATION...JMC/JC MARINE...Goodman/JP HYDROLOGY...Goodman/JP TIDES/COASTAL FLOODING... CLIMATE... EQUIPMENT...