Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 271537 AFDOKX Area Forecast Discussion National Weather Service New York NY 1135 AM EDT Tue Sep 27 2016 .SYNOPSIS... A weakening cold front moves through this morning and stalls just offshore this afternoon. This boundary remains in the vicinity during Wednesday while weak high pressure builds in from the north. Then, low pressure over the Ohio Valley and Mid Atlantic states will meander about this region into the weekend bringing an extended period of unsettled weather. The low will gradually lift through New England early next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Pops adjusted for showers across the region to better match radar reflectivity trends. Showers shift east across SE Connecticut and Eastern Long Island this morning with a weakening cold front. Rain and clouds then diminish behind the front west to east with a dry afternoon anticipated. High temperatures will be near normal but perhaps slightly above normal for the western half of the CWA where clouds will diminish earlier. There is a moderate risk of rip current development at the ocean beaches for today. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/... Looks like the frontal boundary will remain not too far offshore tonight and may begin to drift back towards the CWA by late. High pressure will also be building in from the northeast late at night into Wednesday. This ridging will limit moisture to the low levels. Isentropic lift pushing in from the east could supply enough lift for light rain or drizzle with the best overall chances appearing to be Wednesday afternoon. Will go with slight chc pops tonight, but only over the twin forks region...and then expand pops westward during Wendesday, but capping them at chance. Temperatures are a blend of Superblend, MAV and MET MOS. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... NWP guidance and ensembles are in good agreement with the overall H5 pattern across North America through the first half of the weekend...then solutions begin to diverge with the next trough/cutoff low entering the PacNW although this should not impact the local area until early next week. The long term period starts with cutoff low pres over the Ohio Valley trapped between ridging to the east and west. This will result in the system meandering about this area into the weekend before the ridge to the east finally begins to break down allowing it to track through the eastern Great Lakes and New England early next week. Confidence decreases in the finer details...although a frontal boundary extending from the sfc low in combination with strengthening isentropic lift will result in much needed overrunning rainfall Wed night into Fri morning. While the periods of heavier rainfall remain uncertain there is a signal that Thu night could be one timeframe where heavier pcpn does occur with mid level vort energy passing through. Unsettled pattern will continue into the weekend with abundant cloud cover and perhaps a transition to more showery pcpn with mid level ridging trying to build in from the east. Moisture transport will still be originating from the Gulf of Mexico under this pattern. Warm front may push through on Sun as the system begins to lift through the Great Lakes. This will also push the heaviest rainfall to the north as well...resulting in decreasing PoPs through Mon. The EC remains the western outlier...hanging tough with this soln for the past 3 runs...although it has moved somewhat closer to consensus. Based on the location of the system...heaviest rainfall is expected to fall west of the area. See hydro section for more information on expected totals locally. Removed thunder as the lower heights associated with the deep low are too far west...thus it remains too warm aloft for any elevated instability. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/...
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VFR returning to all terminals and contininung this afternoon and evening. -SHRA affecting KISP AND KGON will end by noon. W-NW flow around 10 kt becoming S-SW in the afternoon. Winds become light and variable this evening before becoming NE around 5 kt early Wednesday morning. ...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: Amendments possible to adjust wind direction timing. KLGA TAF Comments: Amendments possible to adjust wind direction timing. KEWR TAF Comments: Amendments possible to adjust wind direction timing. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: Amendments possible to adjust wind direction timing. KHPN TAF Comments: No unscheduled amendments expected. KISP TAF Comments: No unscheduled amendments expected. .Outlook for 12Z Wednesday through Saturday... .WED...Becoming MVFR late morning/early afternoon. NE gusts to 20 kt possible in the afternoon. .THU-SAT...IFR/MVFR in showers. NE winds 15-20 kt with gusts 25-30 kt possible THU-FRI.
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&& .MARINE... Pops adjusted for showers to better match radar reflectivity trends. Wind gusts on the non-ocean waters have been falling short of advisory criteria and are not expected to strengthen much if any, so have cancelled the SCA for these areas. On the ocean, marginal advisory criteria conditions are expected today. Changes were made east of Fire Island Inlet to shorten the SCA by a few hours based on guidance and trends. Sub-sca conds then prevail tonight, then the pressure gradient tightens on Wednesday with increasing winds. Will probably need another SCA for some of the waters, but with the current headline up, will wait before posting any headlines for that period. SCA conditions all waters Wed night through at least Thu night due to a tight pres gradient across the waters. There still remains a low probability of marginal gale force gusts during this time...thus will continue the mention in the HWO. It may only be confined to the ocean waters however. The GFS is indicating gusts into the 40`s but feel this is overdone. NAM looks more reasonable...but perhaps a tad light. Have used a compromise of the 2 weighted more towards the NAM. Winds subside on Fri as the gradient weakens...although seas on the ocean will remain elevated...possibly into Sat. && .HYDROLOGY... Less than 1/4 inch of rain is expected through this morning. The proximity of a low pressure system late in the week looks to be too far west at the current time for the local area to fall in the axis of heaviest QPF. Currently between 1/2 and 1 1/2 inches of rainfall is forecast between Wed night through Sat. This is not expected to cause any hydrologic impacts. && .TIDES/COASTAL FLOODING... A persistent moderate easterly flow during mid to late week may combine with increasing astronomical high tides associated with the new moon on Friday to cause minor to locally moderate coastal flooding late this week. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until noon EDT today for ANZ355. Small Craft Advisory until 8 PM EDT this evening for ANZ350. Small Craft Advisory until 2 PM EDT this afternoon for ANZ353. && $$ SYNOPSIS...JC/24 NEAR TERM...JC/JM SHORT TERM...JC LONG TERM...24 AVIATION...IRD MARINE...JC/24/JM HYDROLOGY...JC/24 TIDES/COASTAL FLOODING...

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