Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 270255 AFDOKX Area Forecast Discussion National Weather Service New York NY 1055 PM EDT Mon Jun 26 2017 .SYNOPSIS... Weak high pressure builds farther offshore tonight as a cold front approaches from the Great Lakes. The front moves through the area Tuesday evening. High pressure will then briefly follow for the middle of the week. Another frontal system approaches for the end of the week. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
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A weak surface trough was across the region from the Hudson Valley into eastern Pennsylvania and into north central Maryland. This was the focus of a few light showers, along with a shortwave rotating through an upper trough. Put probabilities, slight chance, into the forecast for areas across the far western zones initially and then slowly east through the overnight. The HRRR was also supporting the chance of showers overnight, just a couple of hours too quick. Lower levels are dry and any precipitation reaching the ground is expected to be light. Anomalously strong upper trough across the Great Lakes and Ohio Valley states pivots eastward the next couple of days with gradual height falls and increasing daytime instability.
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&& .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... Airmass gradually destabilizes on Tuesday with height falls and approaching cold front over the Great Lakes. However, dry low- levels and lack of strong surface trigger will be limiting factors for the development of showers/thunderstorms. The best chance will be across the interior during the afternoon hours. Wind shear is also weak, limiting any organization. Cold front works across the area in Tuesday evening with high pressure to follow. Daytime highs will once again be near or just below seasonable levels. There is a moderate risk for the development of rip currents Tuesday. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... High pressure will be in control Wednesday through Thursday night, bringing dry conditions and near normal temperatures across the area. As high pressure moves offshore, warmer temperatures and increasing chances of showers and thunderstorms will develop Friday through Sunday. High pressure builds back on Monday, bringing more seasonable temperatures and dry conditions across the area. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/...
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A weak trough of low pressure over the area will move east late tonight...followed by another one on Tuesday. VFR through the TAF period. An area of showers over SE PA may impact KSWF between 05z and 06z. Latest hi res guidance weakens this activity as it tracks NE next few hours...so will watch and amend as needed. Also a few showers have popped up in northern MD, but is not as much widespread as some of the earlier guidance was indicating. Thus, have decided to hold off on adding showers to other terminals for now. S-SW winds 5-10kt will become light and vrb outside of NYC terminals overnight. Winds will increase 10-15kt Tue aftn with gusts in the upper teens to lower 20s...becoming W-NW around 00z as the trough pushes through. Could be some isold showers/tstms Tue aftn associated with upper disturbance and sfc trough moving through. .OUTLOOK FOR 00Z WEDNESDAY THROUGH SATURDAY... .Tuesday Night-Wednesday...VFR. .Thursday...VFR. Chance of a late day shower/thunderstorm. .Friday and Saturday...Sub-VFR in showers and thunderstorms.
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&& .MARINE...
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Winds and seas forecast on track. With an overall weak pressure gradient remaining across the region, winds and seas are expected to remain below small craft advisory criteria (25kt winds, 5 ft seas) through Tuesday. Below small craft advisory conditions expected Wednesday as High pressure moves south across the area waters. Winds and seas increase, and small craft advisory conditions are possible later Thursday and into Saturday.
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&& .HYDROLOGY...
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No hydrologic impacts expected through the beginning of next week.
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&& .TIDES/COASTAL FLOODING... Astronomical tides are still running high with a low chance of any minor coastal flooding across the south shore back bays of Nassau county with this evening high tide cycle, approximately between 10pm and 12am. The water levels would only be expected to touch the minor benchmarks few just a couple of gages so no statement has been issued. && .EQUIPMENT... Observations from KFRG (Farmingdale, NY) are not available. Observations from KHPN (White Plains NY) and KHVN (New Haven CT) are being disseminated through backup methods. All is due to an FAA communication line outage. Return to service time is unknown. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...Fig/DW NEAR TERM...MET/DW SHORT TERM...DW LONG TERM...Fig AVIATION... MARINE...Fig/MET/DW HYDROLOGY...Fig/DW TIDES/COASTAL FLOODING... EQUIPMENT...

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