Area Forecast Discussion
Issued by NWS Upton, NY

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KOKX 251804 AFDOKX Area Forecast Discussion National Weather Service New York NY 204 PM EDT WED MAY 25 2016 .SYNOPSIS... High pressure builds to the south and east through tonight followed by a weak cold front crossing the area on Thursday. This front then lifts north as a warm front Thursday night, with high pressure building in behind the front through Saturday night. A series of frontal boundaries then impact the area from Sunday into Tuesday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
With high pressure translating off the southeast coast, a sw flow is setting up across the region. The pressure gradient is weak enough and enough land sea temperature differential has led to sea breeze circulations keeping coastal locations relatively cooler than places farther inland. Temperatures are well into the 80s across the region and will reach near 90 for some locations. Sky conditions are sunny without much of any clouds with ridging and thereby subsidence aloft. Temperatures and dewpoints were slightly adjusted to better match observed trends with otherwise no other remarkable changes made to the forecast database.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
-- Changed Discussion --
Deep layered ridging remains in control tonight and Thursday. It will be dry tonight, with only some high clouds around. However, a 700-500 hPa shortwaves passes over the top of the ridge, and through the area Thursday afternoon. This, coupled with surface based CAPE of 500-1000 J/kg, Showalter Indices from -2 to 2, and 20-25kt of Bulk shear over roughly the NW 2/5 of the CWA, warrants slight chance to chance pops in that region. It should be noted that the ECMWF suggests that there should be sufficient subsidence under the ridge to keep things dry throughout the area on Thursday. The GFS however suggests fairly extensive convection over roughly the NW 2/5 of the CWA, with the NAM somewhat in between (though closer to the ECMWF than the GFS). Noting, that in addition to the passing shortwave, will also have a cold front sinking south into the region. Based on this, it appears there is enough forcing to warrant pops at this time. However, there is still the potential for no precipitation at all on Thursday. For lows tonight, a blend of MAV/MET/ECS guidance and NAM 2-meter temperatures was used, with values around 10-15 degrees above normal. A blend of MAV/ECS/MET guidance, NAM 2-meter temperatures and a mix down from 850-750 hPa, per BUFKIT soundings, was used for highs on Thursday. Highs should be around 15 degrees above normal, but probably a degree or so lower than today. If the more extensive convection suggested by the GFS plays out, highs, especially over western areas, might need to be lowered by at least 5 degrees.
-- End Changed Discussion --
&& .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Frontal boundary lifts north of the area as a warm front Thursday night. A southerly flow and ridging aloft will allow for the above normal temperatures to continue Friday and Saturday. It will also mean a noticeable increase in humidity as inland areas will see dewpoints into the lower to middle 60s by Friday afternoon, mainly away from the coast. The relatively cool ocean waters will keep temperatures and dewpoints down along coastal areas. However, temperatures across central Nassau and Suffolk may reach the upper 70s to near 80 on both Friday and Saturday. The warm front then approaches our area again late Saturday night into Sunday morning as a back door cold front. High pressure behind this cold front over southeastern Canada slips off the New England coast and into the western Atlantic during this time period. This high is weaker than in previous model runs, and thus will not push as far into our area as previously forecast. This will help to keep the frontal boundary in the vicinity through Monday morning. Sunday`s temperature may be a difficult one depending on which side of the front we will be on. We will be warm sectored on Monday. However, clouds and will keep temperatures down. A cold front then approaches for Tuesday. Something to watch is the disturbance well off the Southeast coast. Models show this disturbance moving inland over the Southeast coast and having little, if any, impact for our area through the forecast period. However, moisture from this system could make its way into our area on Tuesday, but right now it looks like a low chance of that happening. It is still a few days out with a good deal of uncertainty in the forecast. As far as rainfall, nothing looks organized for the long term. There is a fair amount of moisture available given the humid airmass and surface based CAPE values are high for the afternoons from Friday through Monday, but lift does not look overly impressive. Afternoon showers and thunderstorms are possible for areas north and west of NYC Friday and Saturday. Then there is at least a slight chance for the entire area on Sunday with the approach of the back door cold front, which will remain in the vicinity through Monday. Continued unsettled for Tuesday with the approach of the cold front from the west. None of these days are expected to be a washout, just passing showers and thunderstorms. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
High pressure builds in from the west today. VFR forecast. West winds 8-12 kt will back to the SW through this afternoon. Gusts 17-19 kt through this afternoon. SW winds 5-10 kt this evening at KNYC terminals and LGT/VRB elsewhere. Afternoon sea breezes expected on Thursday. ...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: Occasional gusts 18-22 kt this afternoon. Sea breeze also could back winds to the South through this evening. KLGA TAF Comments: Gusts might be only occasional. Winds might back closer to 250-230 magnetic this afternoon. KEWR TAF Comments: Gusts might be only occasional. KTEB TAF Comments: Gusts might be only occasional. KHPN TAF Comments: Gusts might be only occasional. KISP TAF Comments: Gusts might be only occasional. Winds might back closer to 230-210 magnetic this afternoon. .OUTLOOK FOR 18Z Thursday through Monday... .Thursday afternoon...VFR. Afternoon sea breezes. .Thursday night through Friday morning...Mainly VFR but sub-VFR possible in showers/evening thunderstorms. .Friday through Friday night...Mainly VFR, but sub-VFR possible in isolated showers and evening thunderstorms. .Saturday...Mainly VFR. Isolated showers and thunderstorms north of NYC/Long Island. .Sunday...Sub-VFR possible in afternoon showers and thunderstorms. .Monday...Sub-VFR possible in showers and thunderstorms.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
No hazards are expected today with sub SCA conditions as high pressure builds south of the waters. Outside of afternoon seabreezes bring gusts to around 20 kt to the New York Bight Region this afternoon and Thursday, a light to moderate pressure gradient over the area will keep winds to 15 kt or less through Sunday. With no significant swell forecast, these relatively light winds will keep seas below Small Craft Advisory criteria as well throughout the forecast period.
-- End Changed Discussion --
&& .HYDROLOGY... Dry through Thursday morning. Scattered to Isolated Showers and Thunderstorms, mainly from NYC on N/W Thursday afternoon/evening could bring less than 1/2 inch of rain to that area. There are no significant hydrologic impacts expected from Thursday Night into early next week. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...Maloit/JP NEAR TERM...JM SHORT TERM...Maloit LONG TERM...JP AVIATION...MPS MARINE...JM/Maloit/JP HYDROLOGY...Maloit/JP

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.