Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 151753 AFDOKX Area Forecast Discussion National Weather Service New York NY 153 PM EDT Sun Jul 15 2018 .SYNOPSIS... Weak high pressure will remain in place through tonight with a couple of low pressure troughs moving across the region. A cold front will impact the area from late Monday into early Wednesday, with high pressure returning for the middle of next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Another shortwave trough axis will move across Central and Northern New England this afternoon with some associated positive vorticity advection. At the surface, the region remains in weak high pressure. The next round of convection comes with daytime heating this afternoon and models are focusing on some initiation along higher terrain in the interior and then that convection travels slowly southward. The coverage will be primarily isolated to widely scattered. Max temperatures lowered a few degrees where clouds have prevailed much of the day. Mainly low 80s for highs across the region are expected. Higher POPs for showers and thunderstorms for the interior to for mid to late this afternoon. The higher POPs will move southward and encompass the entire region again. Coastal locations will also have this chance because of potential enhanced convergence from sea breeze boundaries but coverage is not expected to be as much as before. POPs for much of the coast were dropped to below 30 percent. A moderate risk for rip current development is expected at the ocean beaches today.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
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The shortwave exits the region tonight, with some ridging aloft building into the area. Rain chance will quickly drop off this evening as some drier air briefly works into the region. The high will slide offshore on Monday allowing a surface trough and cold front to approach from the west. A south to southwest flow will develop, allowing moisture levels to increase. Monday morning should be mostly dry, however POPs do gradually increase through the day for NYC and points west as some showers and thunderstorms develop as a thermal surface trough develops across the interior. Some of these storms will be capable of producing heavy rainfall and locally gusty winds. some of these thunderstorms may continue into Monday night and gradually spread eastward. Temperatures on Monday will climb into the upper 80s to lower 90s, except across Long Island and coastal Connecticut where highs will remain in the lower to middle 80s. Overnight lows will remain in the upper 60s and 70s both Sunday night and Monday night. A moderate risk for rip current development is expected at the ocean beaches on Monday.
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&& .LONG TERM /TUESDAY THROUGH SATURDAY/... A cold front will move across the region during the early part of the long term period. PW values are expected to be close to the 97th percentile for this time of year on Tuesday, and potentially close to maximum values. Continued forcing for ascent with the approaching trough and attendant cold front will lead to at least isolated showers at any time, quickly increasing into the afternoon as the front approaches at a favorable time, diurnally. Any storms that develop in a discrete manner ahead of the front may produce locally gusty winds with a dry subcloud layer and downward momentum from heavy rainfall enhancing winds. Otherwise, flow will mainly be parallel to the frontal boundary, allowing storms to quickly spread with a line developing by afternoon. Heavy rainfall will be the primary threat until the front passes to the east Tuesday night into Wednesday morning. High pressure then follows, with a return to more seasonable temperatures and humidity levels. There is potential for an area of low pressure to approach from the southwest by the weekend, but details about placement and timing are too uncertain at this time to offer further detail. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/...
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Weak low pressure trough will remain nearby today into tonight. Mostly VFR. Iso/sct tstms mainly after 20-21z and mainly for the terminals north of the city. Winds this afternoon should be SW-S around 10 kt. Winds could be more WSW until 19-20z. A few gusts 15-18 kt possible at KEWR. .OUTLOOK FOR 18Z MONDAY THROUGH FRIDAY... .Monday...VFR to start, then chance of afternoon/nighttime showers/tstms with MVFR or lower flight cat. SW winds G15-20KT in the afternoon for coastal terminals. .Tuesday...AFTN/evening Showers/tstms likely with MVFR or lower flight cat. SW winds G20-25KT into early evening. .Wednesday...Chance of early AM showers with MVFR or lower flight cat, otherwise VFR. .Thursday-Friday...VFR.
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&& .MARINE... Winds and seas will generally remain below small craft levels through Monday. Winds and seas will gradually increase ahead of an approaching front Monday night into Tuesday, with SCA-level seas expected by Tuesday. Some 5 ft seas are expected to remain on the eastern waters through Wednesday before falling back below SCA levels Wednesday night. Thereafter, high pressure builds across the area, allowing winds and seas to subside into late week. && .HYDROLOGY...
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Additional rainfall amounts through early this evening could total up to near a quarter of an inch across the area with locally higher amounts possible. Local amounts above an inch will be possible due to the convective nature of the rainfall. Minor flooding could occur at any point in this period due to a relatively slow forward motion of potentially training cells, but overall flooding chances appear to be low. Another 3/4 to 1 1/4 inch basin avg rainfall likely with the slow moving frontal system from late day Monday into Wednesday morning. Locally heavy rainfall is possible Tuesday afternoon and night, with some potential for minor urban and poor drainage flooding.
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&& .TIDES/COASTAL FLOODING... Astronomical tides will continue to run high due to a combo of a recent new moon and onshore flow/incoming long period swells promoting tidal piling. Additional rounds of localized minor flooding are likely tonight and again Monday night along the back backs of southern Nassau. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off the air for an extended period of time. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...BC/MD NEAR TERM...BC/JM SHORT TERM...BC LONG TERM...BC/MD AVIATION...JC MARINE...BC HYDROLOGY...BC/MD TIDES/COASTAL FLOODING... EQUIPMENT...

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