Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 210457 AFDOKX Area Forecast Discussion National Weather Service New York NY 1157 PM EST Tue Feb 20 2018 .SYNOPSIS... High pressure will remain anchored over the western Atlantic through mid week as a slow moving frontal system approaches from the Mississippi Valley into Wednesday. A cold front will move though Wednesday night and stall to the south late Wednesday night, with a series of weak lows moving along it through Saturday night. A stronger frontal system will eventually pass well to the northwest on Sunday, with its trailing cold front passing through late Sunday. High pressure will then dominate most of early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... Have expanded the dense fog advisory into Nassau, southern Queens, northern New London, and northern Middlesex. The GOES-16 fog product and nighttime microphysics RGB show the expansion of the fog nicely. Surface observations continue to show lowering visibilities, supporting the expansion of the advisory. The dense fog advisory across the remainder of Long Island and SE coastal Connecticut remains unchanged. There may be further expansion N and W overnight if the fog advects further inland. Once challenge with this is larger temperature and dew point spread, especially across NYC and into portions of SW interior CT and the Lower Hudson Valley. Some outlying locations have been able to radiate quicker and have started to see fog development, but this remains isolated for now. The NARRE-TL probabilities for dense fog early Wednesday morning north and west of the current advisory are less than 30 percent. This lines up well with current observations. Fog may still develop but visibilities may not be as low and it could end up being more stratus. Will continue to highlight the potential across the rest of the forecast area in the hazardous weather outlook. Patchy drizzle is also possible tonight. Otherwise, The observed 500 mb height from our 00z RAOB was 5880m, which well above the max observed values for this time of year per SPC Sounding Climatology page. In fact, it is higher than any observed value for January, February, and March. Lows will be well above seasonal norms with a chance of setting record high low temperatures. See record reports and climate section for details. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... With the pattern remaining into Wednesday morning stratus and fog expected to persist into the morning and will carry fog and patchy dense fog 14Z to 15Z, and linger longer across the southeastern zones. With the warm air mass remaining in place record high temperatures will be possible once again. See climate section for more details. A weakening cold frontal boundary begins to move toward the inland region late in the afternoon Wednesday and into the region during the evening. There will be little moisture through the atmospheric column and little lift, so will have only slight chance probabilities, except for western Orange county. The front stalls in the vicinity with the western Atlantic ridge remaining in place. Canadian high pressure to the north will determine how far south the front moves. Then a shortwave will move along the frontal boundary late Wednesday night. && .LONG TERM /THURSDAY THROUGH TUESDAY/... An active weather pattern will last into the weekend. An upper ridge to the south will help steer a number of upper level disturbances across, that should interact with a stalled frontal zone to the south to produce episodes of light to moderate precip one Thu into Thu evening, another late Thu night into Fri evening, and the last this weekend, with a warm front slowly approaching Sat night into Sunday, then a cold front passing through late Sunday afternoon or Sunday night. As strong high pressure builds to the north Thu night into Fri, enough low level cold air should filter in to help produce a mix of rain/sleet across the interior (and sleet/freezing rain in the higher elevations) late Thu afternoon into Thu evening per blended GFS/ECMWF partial thickness profiles, then a more widespread light freezing rain/sleet potential late Thu night into Fri morning ahead of the next wave of low pressure. High pressure should follow for early next week, with a passing upper level disturbance possibly producing a snow or rain shower late Mon night into Tue morning. Temps should be above normal through the period. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... High pressure remains anchored over the western Atlantic through midweek. A slow moving frontal system approaches on Wednesday. VFR conds, gradually deteriorating to IFR or lower for coastal terminals through midnight, possibly working into inland terminals overnight. Moderate potential for LIFR/VLIFR ceilings and visibilities for NYC terminals and coastal terminals late tonight into morning push. Lower confidence on whether these conditions work into KEWR/KTEB/KSWF. Gradual improvement to MVFR/VFR expected through the morning into early afternoon. Improvement may be slightly quicker than today. Chance of showers with MVFR for the evening push. SW wind G15-20KT possible Wed afternoon for KLGA, KEWR, KTEB, KHPN, KSWF. Winds shift to the NW between 01z and 03z with gusts 15 to 20 kt for NYC/NJ terminals. .OUTLOOK FOR 00Z THURSDAY THROUGH SATURDAY... .Wed Night...Chance of showers with MVFR in the evening. Wind shift to the NW with g15-20 kt between 01z and 03z. VFR and subsiding winds overnight. .Thu...MVFR in rain likely for city/coastal terminals, IFR possible. Snow or wintry mix for interior terminals. NE wind G15-20 KT possible. .Fri...IFR possible in rain. Wintry mix possible interior terminals. .Sat and Sun...CHC MVFR in rain. && .MARINE... A dense fog advisory remains in effect on all the waters into Wednesday morning. With a persistent the southwest flow ocean seas east of Fire Island Inlet remain 5 feet or a little higher through Wednesday night. Also, Wednesday into Wednesday night there may be several hours of minimal SCA levels gusts on the eastern ocean waters. So will have a SCA in effect into late Wednesday night. Minimal SCA conds mainly in the form of higher ocean seas should continue from Thu into Thu night, possibly into Fri morning. Another round of SCA conds expected on Sunday, once again in the form of higher ocean seas, as E then SE flow increases ahead of an approaching warm front. These conds could continue into early next week via post-frontal NW flow. && .HYDROLOGY... A series of lows will bring episodes of light to moderate rainfall from Wednesday night into the weekend. Total rainfall of 1 to 1.5 inches over a long duration should preclude any hydrologic impact. && .CLIMATE... Temperatures may approach or break record highs in a few spots Tuesday and Wednesday. Record High Minimum Temperatures for Tuesday February 20, 2018 Location........Record/Year Newark..............46/1939 Bridgeport..........39/2016 Central Park........48/1939 LaGuardia...........44/2002 JFK.................46/1981 Islip...............47/1981 Record Highs for Wednesday February 21, 2018 Location........Record/Year Newark..............69/1953 Bridgeport..........59/2002 Central Park........68/1930 LaGuardia...........68/1953 JFK.................63/2002 Islip...............63/2002 Record High Minimum Temperatures for Wednesday February 21, 2018 Location........Record/Year Newark..............49/2002 Bridgeport..........44/2002 Central Park........50/2002 LaGuardia...........47/2002 JFK.................47/1981 Islip...............45/1996 && .EQUIPMENT... NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) is off the air for an extended period of time. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Dense Fog Advisory until 10 AM EST Wednesday for CTZ007-008- 010>012. NY...Dense Fog Advisory until 10 AM EST Wednesday for NYZ078>081- 177>179. NJ...None. MARINE...Dense Fog Advisory until 10 AM EST Wednesday for ANZ330-335- 338-340-345-350-353-355. Small Craft Advisory until 5 AM EST Thursday for ANZ350-353. && $$ SYNOPSIS...Goodman/19 NEAR TERM...MD/19/DS SHORT TERM...19 LONG TERM...Goodman AVIATION...NV MARINE...Goodman/19 HYDROLOGY...Goodman/19 CLIMATE... EQUIPMENT...

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