Area Forecast Discussion
Issued by NWS Upton, NY

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388 FXUS61 KOKX 252041 AFDOKX Area Forecast Discussion National Weather Service New York NY 341 PM EST Sat Feb 25 2017 .SYNOPSIS... Showers and scattered thunderstorms with a cold frontal passage this evening. Cool high pressure then builds south of the area through Monday. A slow moving warm front will approach from Monday night into Tuesday night, the lift north on Wednesday. Low pressure passing to the north will drag a trailing cold front through late Wednesday night or early Thursday. Another cold front will pass through on Friday. && .NEAR TERM /UNTIL MIDNIGHT TONIGHT/... Need to check the calendar. I can`t recall the last time I`ve seen a line of storms extend from Quebec south to North Carolina in February with nearly 2000 CG in the past hour. Impressive to say the least. Anyway, SVR Watch 40 up until 02Z (which we`ll be able to cancel around 00Z) for west of the Hudson - as well as Putnam, NY. There`s plenty of shear which has prompted the inclusion of a possible tornado in the Watch. The best thermodynamics are over SE PA where the 20Z SPC Meso Analyses shows 1000 J/Kg of SBCAPE and LI`s of -4 C. Thus, expect storms to get well into the western zones before they weaken rapidly as they start to ingest the marine air. For the NY Metro - the loss of daytime heating and the marine air support not extending the watch to the east. That being said, still expect a gust to 30 to perhaps 40 KTS in the 00Z time frame. The rain ends quickly overnight and northwest winds usher in a more seasonal airmass. && .SHORT TERM /MIDNIGHT TONIGHT THROUGH SUNDAY NIGHT/... Seasonable weather returns for Sunday. NW winds gust up to 30 mph through the day and then diminish at night. With clear skies and light winds, expect decent radiational cooling Sunday night. Temperature guidance remains consistent and was accepted. && .LONG TERM /MONDAY THROUGH SATURDAY/... NWP guidance fairly close through the period, though did side with slower NAM at first with approaching weak mid level shortwave moving through a flat upper longwave ridge. After that, went with a 00Z ECMWF/12Z GFS blend, with increasing chances of rain in large scale WAA, and likelihood of rain Tue night through Wed night ahead low pressure passing to the north and an approaching trailing cold front. As mild/humid air streams northward with dewpoints in the 50s, fog likely Wed night that could be dense along the coast. Cold fropa late Wed night could be accompanied by brief heavier showers. After cold fropa on Thu, drier/colder air will arrive on a gusty W then NW flow, with wind gusts 30-40 mph possible especially NYC metro and coastal sections. Another cold frontal passage expected late Friday, and kept fcst dry but did increase clouds with its approach/passage. Temps should remain on the mild side through Thu, with at least 50s each day and lower 60s for NYC metro/NE NJ on Wed. Much colder for Thu night and beyond, with lows in the lower 30s NYC metro and 20s elsewhere Thu night and Sat night, and even colder Fri night, with teens and 20s. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... A cold front moves across this evening with high pressure building in from the west thereafter. Mainly MVFR to VFR conditions this afternoon and some isolated IFR with some lingering low level stratus. Low level stratus will eventually scatter out leaving MVFR/VFR stratus. With the cold front for city terminals and terminals KHPN and KSWF, expecting a brief period of showers and embedded thunderstorms while to the east, just a brief period of showers is expected in a general timeframe from west to east of 22Z-03Z. After this, mainly VFR conditions are expected. Winds will be SE veering to S with wind speeds near 10 kt gusting at times to 15-20 kt. After the cold frontal passage, an abrupt shift in wind direction and speed is expected as winds veer to W-WNW near 15 kt gusting 25-30 kt. Winds could occasionally peak a few kts higher than forecast. .OUTLOOK FOR 18Z SUNDAY THROUGH THURSDAY... .Sunday...VFR. NW winds G20-25KT likely. .Sunday night-Monday evening...VFR. W-SW winds G15-20KT Monday. .Late Monday night-Thursday...Chance of MVFR or lower at times with any showers. W-NW winds G20-30 KT Thursday. && .MARINE... Small craft advisory (SCA) on the coastal waters for through the day on Sunday in the wake of a cold frontal passage this evening. SCA conditions will linger through Sunday night on the Ocean waters as winds slowly subside, but seas will remain at or above the 5 FT criteria. Mon into Mon Eve: SCA for the eastern ocean waters via favorable WSW fetch of 15-20 kt wind on northern periphery of offshore high pressure. Wed afternoon/night: SCA conds on the ocean waters via increasing S- SW flow ahead of an approaching low pressure system. Dense fog likely to develop as very moist air moves over the colder waters. Thu into Thu night: Cold fropa followed by W-NW gales on the ocean and SCA conds elsewhere. && .HYDROLOGY... Around a half inch of rain with locally higher amounts can be expected through tonight. Rainfall of 1/2 to 3/4 inch possible from Tue night into Thu morning. No hydrologic issues expected. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory from 6 PM this evening to 6 PM EST Sunday for ANZ330-335-338-340-345. Small Craft Advisory until 6 PM EST Sunday for ANZ350-353-355. && $$ SYNOPSIS...Goodman/Tongue NEAR TERM...Tongue SHORT TERM...Tongue LONG TERM...Goodman AVIATION...JM MARINE...Goodman/Tongue HYDROLOGY...Goodman/Tongue

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