Area Forecast Discussion
Issued by NWS Upton, NY

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938 FXUS61 KOKX 200257 AFDOKX Area Forecast Discussion National Weather Service New York NY 957 PM EST Mon Feb 19 2018 .SYNOPSIS... High pressure remains anchored over the western Atlantic through mid week as a slow moving frontal system approaches from the Mississippi Valley. The associated warm front will work north across the area this evening. A cold front moves across Wednesday night. A series of lows will be moving through the Northeast late this week into the weekend. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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Fog continues to move into the area, with visibilities of 1/2 mile noted in some obs. Have issued an SPS for patchy dense fog for portions of northeast NJ, Lower Hudson Valley, and southwest CT. Will continue to monitor trends with the possibility of issuing a Dense Fog Advisory later tonight. A more likely scenario would be to issue an SPS over other areas of the CWA where patchy dense fog develops later tonight. Otherwise, forecast is on track. A record warm pattern sets up as an anomalously strong upper ridge over the western Atlantic strengthens through mid week. At the same time, a slow moving frontal system associated with an upper trough over the western states work east from the Mississippi Valley. This will place the region in a warm, deep- layered SW flow. A warm front will move across the area tonight preceded by light overrunning rain. Much of the rain will exit the area by midnight with areas of fog and patchy drizzle forming. Temperatures will remain steady if not slowly rise overnight. Lows will be about 15 to 20 degrees above normal, in the 40s.
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&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... Low clouds, fog, and patchy drizzle will likely start the day on Tuesday with some clearing expected in the afternoon as some warmer, drier air mixes down from aloft. The high res NAM (3km) maintains a strong low-level inversion across the area and maintains saturated low-levels for all but the far interior. This is likely overdone based on past performance and the preference is to go with some improvement. There is though more uncertainty near the immediate coast. Temperatures in this type of airmass will also be tricky with an onshore flow keeping coastal areas much cooler than the interior, where highs will be near record levels. Preference was toward the a MET/MAV MOS along the coast, and the warmer MAV across the interior. Some interior locations will approach 70. Areas of fog and drizzle are likely to develop Tuesday night in the warm, moist airmass, as dew points get into the lower 50s. This will be due to both an advection fog off the cooler marine waters, and radiation fog inland where the SW flow becomes light. Lows Tuesday night will approach 30 degrees above normal, generally in the 50s. These readings will likely break record warmest lows. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... The very active and mild weather pattern will remain in place but will become less mild late this week into the weekend. This is due to a strong Southwest Pacific jet that will remain north of the region through the long term period. It`s quite strong looking at model projections of this jet which convey 190+kt extending from Great Lakes northeast through Canadian Maritimes Wednesday through Thursday. Thereafter, the jet structure remains the same but the magnitude decreases. At the surface, a very busy weather period is in store with several systems moving across. Some notable features include areas of fog going into Wednesday especially along the coast and very warm temperatures continuing Wednesday. Forecast highs Wednesday upper 50s for the Twin Forks of Long Island to lower 70s N/W of NYC. The warmth is not as much for the rest of the forecast period but highs most days looking at Thursday through early next week are forecast to be about 5-10 degrees above normal. The other remarkable feature will be chances of rain which is forecast Wednesday afternoon into Wednesday night as well as Thursday and then again Friday afternoon through the weekend. The periods of rain look to be mostly light to perhaps moderate at times. Early next week, drying conditions are forecast. High pressure moves farther southeast into the Western Atlantic Wednesday. A cold front moves across Wednesday night. The front moves south of Long Island Thursday but stalls with an area of low pressure developing along it. The low and front move farther offshore southeast of Long Island Thursday night with high pressure briefly building in from the north. The high will be moving quickly off the New England coast Friday with another frontal system moving in from the west. Once again, there will be a lingering front behind the system and another low developing along it for the weekend. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/...
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A warm front approaches the area tonight, then lifts north of the terminals on Tuesday. Conditions expected to deteriorate to IFR or lower overnight into morning push. Gradual improvement to MVFR then VFR during later in the morning into afternoon for NYC/NJ and NW terminals, but eastern terminals may remain IFR all day. S/SW gusts to 20 kt possible for KEWR/KTEB/KSWF in the afternoon if VFR conditions develop. Late day S15g20kt coastal jet development possible for JFK into LGA. Elsewhere occasional SW gusts of 15 to 20 kt possible. LLWS possible for SW winds around 2 kft at 35-40 kt. 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: Timing of improvement to MVFR in the morning and then VFR in the afternoon may be 1 to 2 hrs slower than forecast. Possible southerly coastal jet of 15g20kt in the late afternoon. KLGA TAF Comments: Timing of improvement to MVFR in the morning and then VFR in the afternoon may be 1 to 2 hrs slower than forecast. Possible southerly coastal jet with g15-20kt in the late afternoon. KEWR TAF Comments: Timing of improvement to MVFR in the morning and then VFR in the afternoon may be 1 to 2 hrs slower than forecast. SW gusts to 20 kt possible in the afternoon. KTEB TAF Comments: Timing of improvement to MVFR in the morning and then VFR in the afternoon may be 1 to 2 hrs slower than forecast. SW gusts to 20 kt possible in the afternoon. KHPN TAF Comments: Timing of improvement to MVFR in the morning and then VFR in the afternoon may be 1 to 2 hrs slower than forecast. KISP TAF Comments: IFR conditions may persist through the day. .OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY... .Tue Night...IFR or lower in stratus/fog possible at night. .Wed...Improving to VFR. Chance of showers with MVFR in the evening. SW wind G15-20KT possible. Winds shift to the N at night. .Thu...MVFR in rain. NE wind G15 KT possible. .Fri...CHC MVFR in rain. .Sat...CHC MVFR in rain.
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&& .MARINE... Patchy fog is possible over the waters tonight. Will have to watch for the possibility of dense fog developing later tonight with abundant low level moisture. A prolonged period of S-SW winds ahead of a slow moving frontal system approaching from the Mississippi Valley will produce marginal SCA conditions later tonight into Wednesday night on the ocean waters east of Fire Island Inlet. However, current SCA only goes out through the day Wednesday as confidence at this time is too low to extend into Wednesday night. Aside from Wednesday into Wednesday evening with some seas of 5 ft on the ocean, sub-SCA conditions are forecast across the waters for the rest of the week into the weekend. It`s a relatively quiet period with the pressure gradient remaining weak. && .HYDROLOGY... Less than 1/4 inch of rainfall is expected through tonight. Several rounds of rain are possible late this week into the upcoming weekend, but no significant hydrologic impacts are anticipated at this time. && .CLIMATE... Temperatures may approach or break record highs in a few spots Tuesday and Wednesday. Record Highs for Tuesday February 20, 2018 Location........Record/Year Newark..............70/1939 Bridgeport..........54/1991 Central Park........69/1939 LaGuardia...........63/1943 JFK.................61/1949 Islip...............62/2016 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 && .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...
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CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 6 PM EST Tuesday for ANZ350-353.
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&& $$ SYNOPSIS...JM/DW NEAR TERM...JP/DW SHORT TERM...DW LONG TERM...JM AVIATION...BC MARINE...JM/DW HYDROLOGY...JM/DW CLIMATE... EQUIPMENT...

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