Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 180909 AFDOKX Area Forecast Discussion National Weather Service New York NY 409 AM EST Mon Feb 18 2019 .SYNOPSIS... Low pressure passes to the south and east during the day today. High pressure then builds across the area tonight through Wednesday, followed by another low pressure system for Wednesday night into Thursday. High pressure then returns for Thursday night into Friday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Radar returns early this morning show the most persistent precipitation across the Lower Hudson Valley and southern Connecticut, with another batch generally remaining south of Long Island. At this time, any snow is largely confined to far northern portions of the interior, where temperatures remain in the upper 20s. Closer to the coast, a mix of snow, sleet, freezing rain, and rain is occurring with temperatures a degree or two either side of freezing. While additional snowfall accumulations through this morning will generally remain an inch or less, the Winter Weather Advisory remains in effect across the northern half of the area due to the potential for a trace to a few hundredths of an inch of ice accumulation in any freezing rain. Pockets of freezing rain are possible early this morning across portions of Long Island as well, although temperatures there should rise above freezing in the next several hours. A SPS has been issued to address this concern. Otherwise, as low pressure passes south of the area this morning and then off to the east this afternoon, precipitation will come to an end from west to east across the area today. With temperatures warming into the mid 30s to around 40 by noon, the wintry mix will gradually transition to all rain as precipitation comes to an end. Cold air advection on the back side of the system will result in gusty northwest flow this afternoon, making highs in the upper 30s to mid 40s feel several degrees colder. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... High pressure begins to build into the region tonight, with northwest winds gradually diminishing overnight. Under clearing skies, lows will fall into the teens and 20s, with highs on Tuesday only rebounding into the 30s despite plenty of sunshine. These temperatures are about five degrees below normal for this time of year. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Progressive and active pattern expected mid week through the weekend. Two systems to watch this time frame, with western shortwave energy passing well NW of the area. For the mid week system, sfc high not favorable for cold air damming per latest 00Z model suite with high passing to the east. Dry weather with passing high pressure Tuesday night gives way to next low passing across the Great Lakes, with mid Atlantic low development passing near or just south Wed night-Thu. Although forcing with this system does not look to be overly strong, deep layered lift ahead of shortwave combined with gulf tap, would anticipate a moderate precip event for late Wed into Thu morning. Thermal profiles appear cold enough to start as all snow Wed/Wed eve, then transitioning to wintry mix interior and all rain city/coast Wed night into Thu morning, before tapering off Thu afternoon as mid-level shortwave passes. General potential for light snow accum of 1-3 inches and a few hundredths of ice accum, but this could change. Obviously higher accums expected across the interior. Thereafter, generally zonal PAC influenced upper flow for late week into the weekend, lending to slightly above seasonable temps. Similar if not stronger shortwave passes well NW, with perhaps deeper sfc low passing well to the west late next weekend. With available gulf moisture, this energy will likely bring the next chance of significant precip from low pressure/s. At this point too much uncertainty in evolution to diagnose p-types, but would general lean toward liquid vs frozen attm. && .AVIATION /09Z MONDAY THROUGH FRIDAY/... Low pressure passes southeast of Long Island today with high pressure then building in tonight into Tuesday. Light winds under 10 kt will become E-NE early this morning. The flow will become NW by afternoon and increase into the evening with gusts developing, mainly 20-30 kt, highest near the city terminals. Gusts will gradually weaken tonight. Conditions will be mainly IFR to LIFR. The predominate precipitation type at NYC and Long Island terminals will be rain with Long Island still having some pockets of light freezing rain before 10Z. The precipitation should taper off to a drizzle at the coast and freezing drizzle inland after day break. Conditions gradually improve this afternoon. The more wintry precip of snow, sleet, and freezing rain will be across KSWF, with mainly freezing rain for KHPN, KBDR, and KGON. For KSWF there remains potential for 1 to 3 inches of snow/sleet early this morning and up to around 1 inch at HPN, BDR, and GON with a glaze of ice for KSWF, KHPN, KBDR and KGON. ...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 for changing of categories today, particularly the timing of improving conditions which could be a few hours different from TAF. The afternoon KJFK haze potential forecast is YELLOW, which implies slant range visibility 4-6SM outside of cloud. KLGA TAF Comments: Amendments likely for changing of categories today, particularly the timing of improving conditions which could be a few hours different from TAF. The afternoon KLGA haze potential forecast is YELLOW, which implies slant range visibility 4-6SM outside of cloud. KEWR TAF Comments: Amendments likely for changing of categories today, particularly the timing of improving conditions which could be a few hours different from TAF. The afternoon KEWR haze potential forecast is YELLOW, which implies slant range visibility 4-6SM outside of cloud. KTEB TAF Comments: Amendments likely for changing of categories today, particularly the timing of improving conditions which could be a few hours different from TAF. KHPN TAF Comments: Amendments likely for changing of categories today, particularly the timing of improving conditions which could be a few hours different from TAF. KISP TAF Comments: Amendments likely for changing of categories today, particularly the timing of improving conditions which could be a few hours different from TAF. .OUTLOOK FOR 09Z TUESDAY THROUGH FRIDAY... .Tuesday...VFR. NW winds G20-25kt diminishing Tuesday morning. .Wednesday...Snow possible with MVFR or lower conditions in the afternoon and evening, changing to a wintry mix at night. .Thursday...MVFR or lower in a wintry mix inland and rain at the coast in the morning. NW gusts 15-20 kt possible in the evening. .Friday...VFR. && .MARINE... Quiet conditions on the waters this morning will give way to SCA conditions by afternoon, as winds and seas increase in the wake of a departing area of low pressure. The SCA was expanded to include all of the non-ocean waters this evening through the overnight hours. Conditions will quickly fall back below SCA levels Tuesday morning as high pressure builds over the waters. High pressure continues to build Tuesday night and passes east Wednesday. Tranquil winds and seas are expected. Winds shift around to the E/SE and will increase Wed night ahead of low pressure and associated frontal system. Seas build as a result. The low moves east Thursday and winds will shift around to the W. The westerly fetch will result in rougher seas over eastern waters. Conditions improve Thu night and Friday as high pressure builds. && .HYDROLOGY... There are no hydrologic concerns through Tuesday. A wintry mix to rain occurs later Wednesday through Wednesday night. No hydrologic issues are expected. Another system may result in more wet weather later next weekend. Too early to tell if this system will result in any hydrologic issues. && .TIDES/COASTAL FLOODING... A full moon Tuesday along with easterly winds early this morning will result in localized minor coastal flooding with this high tide cycle. Affected areas will be the most vulnerable locales of the south shore bays of Queens and Nassau County, W Long Island sound, and along lower NY/NJ Harbor. Surge of 1 to 1 1/2 ft and, locally 2 ft, is needed for minor flood thresholds to be reached. Feel several locations just reach minor coastal flooding benchmarks. && .EQUIPMENT... NYC Central Park winds are out of service until further notice. Loss of data is due to a severed cable. Parts are on order. NYC NOAA Weather Radio Station KWO35 (162.55 MHz) will remain off the air for an extended period of time. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Winter Weather Advisory until 10 AM EST this morning for CTZ005>012. NY...Winter Weather Advisory until 10 AM EST this morning for NYZ067>071. NJ...Winter Weather Advisory until 10 AM EST this morning for NJZ002-004-103>105. MARINE...Small Craft Advisory from 5 PM this afternoon to 7 AM EST Tuesday for ANZ330-335-338-340-345. Small Craft Advisory from noon today to 7 AM EST Tuesday for ANZ350-353-355. && $$ SYNOPSIS...FEB/PW NEAR TERM...FEB SHORT TERM...FEB LONG TERM...PW AVIATION...JM MARINE...FEB/PW HYDROLOGY...FEB/PW TIDES/COASTAL FLOODING... EQUIPMENT...

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