Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 171449 AFDOKX Area Forecast Discussion National Weather Service New York NY 1049 AM EDT Wed Oct 17 2018 .SYNOPSIS... A strong cold front passes through the region this afternoon and evening. Canadian high pressure then builds across eastern States through Thursday. High pressure along the Mid Atlantic coast Friday gives way to another strong cold front approaching from the Upper Midwest. The front passes through the area Saturday afternoon with high pressure to follow through early next week. A weaker cold frontal passage is forecast for Tuesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A vigorous middle level vort max approaches the area this morning and passes overhead in the afternoon. The vort max is associated with a digging longwave trough that will help to send a strong cold front into the Tri-State today. A cold front enters the NW early this afternoon and then should move offshore this evening. Forecast soundings show a deepening mixed layer with a gusty W-SW flow of 30 to 40 mph this afternoon. Temperatures will warm close to normal levels in the upper 50s and lower 60s ahead of the front. While overall moisture return is not impressive, the strong dynamics aloft with the vort max and approaching upper trough should be enough for a few to sct showers to develop. Some high resolution models indicate a broken line of showers along the front, which could produce a brief downpour and wind gusts to 45-50 mph. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/... The cold front moves offshore this evening with strong cold advection occurring behind its passage. The pressure gradient will tighten tonight as Canadian high pressure builds towards the local area. Winds will stay gusty through the night, but will usher in the coldest airmass of the fall season. 850 mb temperatures drop to around -10C, which is more then -15C below normal for this time of year. Temperatures will fall into the 30s for most locations with the possibility of readings near 32 across the interior. There will not be frost development due to the winds staying elevated and dew points dropping into the low 20s early Thursday morning. Have issued a freeze watch for western Passaic county, interior Lower Hudson Valley, and interior southern Connecticut for early Thursday morning. The strong winds should prevent temperatures from falling much below freezing and confidence is not high enough at this point for a warning. If future trends indicate temperatures will fall lower or winds will be weaker, than a freeze warning may be needed for these zones. The strong NW flow may also bring in some lake effect moisture into the Lower Hudson Valley tonight. While the chance is very low, it is not impossible to see a streamer make it down in the NW flow with a few snow flurries or light rain showers. The anomalously cold temperatures will continue on Thursday. Cold advection continues through much of the day. It will still be breezy as the core of the high remains to our west. Temperatures will struggle to reach 50 degrees, with most locations in the middle and upper 40s for highs. These temperatures are close to the normal lows for this time of year and may end up very close to the current record minimum high temperatures for October 18th. See climate section below. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... With a high amplitude ridge remaining across western North America through the period, a series of upper troughs will drop southeast across eastern Canada and Northeast. Each of which will send a series of cold fronts across the region with a prolonged stretch of unseasonably cool weather from Saturday night into Tuesday. The first cold front will pass through the area Saturday afternoon with a low chance of showers from late Friday night into Saturday. A few showers may linger into Saturday night, mainly north and west of NYC with the passage of the upper trough. Pre- and post-frontal wind gusts up to 30 mph are expected Saturday into Sunday. High pressure will then build to the south and west Sunday into Monday with weaker cold frontal passage to follow for Tuesday. A dry frontal passage is forecast at this time. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... A strong cold front will move across the region this afternoon. Mainly VFR conditions expected. Some possible showers late this afternoon into early this evening may present brief MVFR conditions. Probabilities too low to include in TAFs at this time. Main issue will be gusty W-WNW winds through tonight. Gusts start out 20-25 kt into the start of this afternoon and then increase to near 30 kt during the afternoon. Peak gusts expected mid afternoon into early evening with gusts in the 30-35 kt range. Winds decrease tonight with gusts near 24-28 kt and then closer to 20 kt for Thursday. ...NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component fcsts, can be found at: http:/www.weather.gov/zny/n90 KJFK TAF Comments: Amendments possible this afternoon and evening with possibility of brief MVFR and timing of highest gusts. The afternoon KJFK haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KLGA TAF Comments: Amendments possible this afternoon and evening with possibility of brief MVFR and timing of highest gusts. The afternoon KLGA haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KEWR TAF Comments: Amendments possible this afternoon and evening with possibility of brief MVFR and timing of highest gusts. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: Amendments possible this afternoon and evening with possibility of brief MVFR and timing of highest gusts. KHPN TAF Comments: Amendments possible this afternoon and evening with possibility of brief MVFR and timing of highest gusts. KISP TAF Comments: Amendments possible this afternoon and evening with possibility of brief MVFR and timing of highest gusts. .OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY... .Thursday...VFR. NW winds 10-15G20-25KT. .Friday...VFR. .Saturday...Chance of showers and accompanying MVFR conditions. SW winds 10-15G20KT. .Sunday...VFR. W-NW winds G15-20KT. && .MARINE... The pressure gradient increases today ahead of an approaching cold front. Winds and seas will increase through the day and there has been no change made to the current SCA hazards in effect. The cold front moves to the east of the waters this evening and this will bring another increase to the winds to gale force tonight into early Thursday morning with steepening lapse rates over the waters. The gale warning will continue to run until 10z Thursday. Gales may linger a few hours beyond that time east on the waters east of Moriches Inlet, but did not have confidence on extent and duration to extend the warning here. Otherwise, Small craft conditions are expected on all waters Thursday as the pressure gradient remains tight. A prolonged period of strong SCA conditions will occur Friday into Sunday with the approach and passage of a strong cold front. The front moves through the waters Saturday afternoon with high pressure building in from west on Sunday. && .HYDROLOGY... No widespread significant hydrologic issues are expected through the weekend. && .CLIMATE... Here are the record Minimum High Temperatures for Oct 18th. Location.................Temp/Year Central Park...............45/2009 John F Kennedy Airport.....49/2009 LaGuardia Airport..........47/2009 Newark, NJ.................47/2009 Bridgeport, CT.............47/2009 Islip, NY..................47/2009 && .EQUIPMENT... NYC NOAA Weather Radio Station KWO35 (162.55 MHz) remains off the air for an extended period of time. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Freeze Watch from late tonight through Thursday morning for CTZ005>008. NY...Freeze Watch from late tonight through Thursday morning for NYZ067-068. NJ...Freeze Watch from late tonight through Thursday morning for NJZ002. MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ330- 335-338-340-345. Gale Warning from 6 PM this evening to 6 AM EDT Thursday for ANZ330-335-338-340-345-350-353-355. Small Craft Advisory until 6 PM EDT this evening for ANZ350- 353-355. && $$ SYNOPSIS...DS/DW NEAR TERM...DS/NV SHORT TERM...DS LONG TERM...DW AVIATION...BC/JM MARINE...DS/NV/DW HYDROLOGY...DS/DW CLIMATE... EQUIPMENT...

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