Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 180247 AFDOKX Area Forecast Discussion National Weather Service New York NY 1047 PM EDT Tue Apr 17 2018 .SYNOPSIS... A series of surface troughs will move across through Wednesday as low pressure tracks slowly north across the Canadian Maritimes. Another deepening low will approaches from the southwest Wednesday night, move across on Thursday, and then slowly pull up into the Canadian Maritimes on Friday. High pressure will then build in this weekend into early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... A mid level shortwave trough will push east of the area around midnight with any lingering pcpn across eastern zones coming to an end. Dry weather then prevails through the overnight. Weak cold air advection behind the shortwave may result in and gusty west winds, especially in the metro area. There will be partial clearing as well, especially after midnight. Lows will drop into lower 30s across the interior, and in the mid and upper 30s elsewhere. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... Shortwave ridging and warm advection on Wednesday will result in a dry, milder day with highs in the mid to upper 50s, which is still a few degrees below normal. Gusty West winds will continue as well before weak high pressure builds across the area in the evening. This will be short-lived though as another amplifying shortwave trough over the Great Lakes and Ohio Valley states sends low pressure toward the area late. Decent thermal forcing ahead of the system will result in increasing clouds and light overrunning rain spreading in from the SW, mainly after midnight. Lows will be considerably warmer with the approach of a warm front and the cloud cover across the area, ranging from the upper 30s well inland to the upper 40s NYC metro. && .LONG TERM /THURSDAY THROUGH TUESDAY/... A somewhat blocky pattern aloft will persist through much of the forecast period. Low pressure will move across on Thursday, and with most of the thermal forcing to the north/east, expect light rain/drizzle to start the day. The associated cutoff low aloft will move slowly across New England on thu and into the Canadian Maritimes on Fri, and as it does so, first a potent mid level vort max rotating around it should produce showers from late Thu morning into Thu afternoon, followed by lower chances for rain/snow showers Thu night into Fri as low level cyclonic flow persists and additional weaker vort maxima rotate around. Temps will be on the cool side, running 5-8 degrees below average. As the cutoff low slowly releases its grip on the area, sfc high pressure will start to build in over the weekend and dominate early next week, with one more day of temps well below average on Sat, then moderation to near to slightly above average temps early next week. The combo of an approaching weak cold front and low pressure passing off to the south (and likely tracking farther north than model forecasts) may bring some initial chances for showers going into mid week. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... A surface trough moves east of the terminals through 05Z. Weak high pressure builds into Wednesday afternoon. A wave of low pressure approaches toward 00Z Thursday. VFR. A chance of MVFR ceilings with light rain and snow along the Connecticut coast and eastern Long Island through 05Z. West winds 10 KT or less outside the NYC terminals with 10-15 KT, gusting to around 20 KT at the NYC terminals through tonight. Gust overnight may be more occasional. West winds and gusts will be a few knots higher during Wednesday, winds become more SW, and diminish and gusts ending around 22Z. .OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY... .Wednesday night-Thursday night...MVFR or lower possible in rain, rain/snow showers THU night. NW winds G20-30KT Thursday afternoon. .Friday...VFR. Possible lingering rain/snow showers mainly during the day. NW winds G25-30KT. .Saturday-Sunday...VFR. && .MARINE... SCA conditions will continue across the waters into Wednesday as low pressure over the Canadian maritimes slowly lift to the north. Conditions will gradually improve from west to east on Wednesday with high pressure briefly building in the evening ahead of low pressure in the Ohio Valley. After the low passes by on Thu, NW flow with SCA conds should develop on all waters by Thu night and last into daytime Fri, and the outer ocean waters may flirt with minimal gale force Thu night. Rough ocean seas should linger into Fri night, then quiet conditions expected this weekend. && .HYDROLOGY... Rain amounts below a half inch are expected Wednesday night through Thursday evening with no hydrologic impacts anticipated. Dry weather follows thereafter. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off the air. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 6 AM EDT Wednesday for ANZ335-338. Small Craft Advisory until 4 PM EDT Wednesday for ANZ330-340- 345-355. Small Craft Advisory until 6 PM EDT Wednesday for ANZ350-353. && $$

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