Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 241534 AFDOKX Area Forecast Discussion National Weather Service New York NY 1134 AM EDT Sun Jun 24 2018 .SYNOPSIS... A cold front crosses the area this afternoon and evening followed by high pressure building in through mid-week. A warm front then approaches from the southwest Wednesday, then slowly lifts to the northeast into Thursday. A weak cold front will then approach on Thursday and possibly dissipate over the region Friday into Saturday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Northern stream shortwave ridging will exit to the east by around midday, as a stronger 700-500 hPa shortwave trough approaches late in the day. This feature will interact with an atmosphere that should destabilize fairly rapidly this afternoon, especially to the N/W of NYC. CAPE is progged to reach 1000-1500 J/kg by late afternoon over NE NJ/Lower Hudson Valley interior SW CT, so should have sufficient dynamics and thermodynamics to produce mainly scattered showers and thunderstorms this afternoon. In addition with 40-45 kt of bulk 0-6km shear progged over this region by late afternoon, plus the region being progged in the left front quadrant of an 85 kt 300 hPa jet streak, could see some strong to possibly severe thunderstorms as well. The question then becomes for areas outside of the Lower Hudson Valley/NE NJ/SW Ct is how well do the storms hold together as they head east into areas under a marine influence. This will determine impacts elsewhere. Storms moving into NYC or coastal CT by 21-22Z have a greater likelihood to be strong or severe than those moving in around 0Z or later. Still appear on track for highs mainly from around 80 to the mid 80s, except mainly mid-upper 70s near the immediate coast. There is a high rip current risk at the eastern Suffolk County beaches, and a moderate rip current risk elsewhere. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... A cold front passes across the area from west to east early tonight. Weakening showers and thunderstorms will accompany this front and h5 shortwave. Along the coast, patchy fog is possible in the evening ahead of the front, but should scour out overnight as drier air filters in behind the front. Lows tonight will range from the lower 60s to the upper 60s per mos blend. On Monday, sunshine returns, with perhaps a few more clouds across eastern locations (SE CT and Eastern LI). A few showers are possible over these eastern locations, but the bulk of the shower activity should pass from NW to SE over eastern New England. This activity will be associated with cyclonic flow as trough axis pushes east. Temperatures will rise to the upper 70s to lower 80s. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... High pressure builds Monday night, and NW winds will diminish. With clear skies and lighter winds, some radiational cooling will take place across the usual locations. The high pressure center moves through on Tuesday with sunny conditions and highs slightly cooler, but still close to normal. The high will be to our east on Wednesday, and a return SW flow will bring warmer and more humid conditions. It appears the daytime hours for most areas will be dry as showers ahead of an approaching warm front remain to the west. The warm front moves through, then a cold front slowly approaches Thursday into Friday. A surface trough likely forms over the area ahead of the cold front. It`s beginning to look more likely that the front never makes it through the entire region and instead dissipates nearby sometime Friday into Saturday. Will maintain slight chance to chance PoPs Wednesday night through Friday, then go with a dry forecast thereafter. Rising temperatures aloft will allow for highs around 90 in the city and some inland areas Thursday. 90s then become more widespread across the tri-state area for Friday and Saturday. A south to southwest flow along with sufficiently high dewpoints through the top of the mixed layer would limit the magnitude of surface dewpoints mixing-out each afternoon. Heat advisory criteria could therefore be met in this period, particularly Friday and Saturday. && .AVIATION /16Z SUNDAY THROUGH THURSDAY/...
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A warm front will slowly move through the terminals this morning, followed by a cold front this evening. Gradual improvement occurring mostly as anticipated, except out east at KISP/KGON where VFR not expect until afternoon. Scattered showers/tstms should accompany the cold frontal passage late this afternoon into early this evening. Most likely time frame appears to be 20Z-23Z KSWF, 21Z-01Z KHPN and most of the NYC metros, 22Z-02Z KJFK/KBDR. Confidence level has increased enough to mention vicinity impact and CB, but not enough to get specific in terms of flight cat reductions or wind gusts. Reasonable worst case direct impact would be brief IFR vsby and W-NW winds G35-40KT. SW to S winds will strengthen through the afternoon, then become NW following the cold frontal passage tonight. Gusts will be possible by Monday morning, with flow gradually decreasing through the day. .OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY... .Monday-Wednesday...VFR. NW-N winds G15-25KT Monday-Monday night. S-SW winds G20-25KT possible Wednesday. .Wednesday night-Thursday...MVFR or lower probable. Showers are also probable and there is a chance of thunderstorms as well. SW winds G15-25KT possible.
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&& .MARINE... Sub-Small Craft Advisory (SCA) conditions are expected on the waters this afternoon. Isolated gusts to near SCA-levels are possible tonight (outside of any thunderstorms). Conditions are then expected to remain tranquil Monday through Tuesday with a relaxed pressure gradient developing over the waters. Thereafter, the pressure gradient tightens resulting in a strengthening S-SW flow and SCA-level gusts possible on all waters Wednesday afternoon through Thursday evening. Ocean seas will increase to SCA- levels in response to the strengthening and prolonged south-southwest flow. && .HYDROLOGY... There could be a few locally heavy downpours this afternoon and evening. However, no hydrologic impacts are anticipated. Areal average rainfall totals will be under 1/2 inch, but heavier storms could still produce locally up to an inch. No hydrologic impacts are expected from Monday through the rest of the forecast period. && .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...High Rip Current Risk until 9 PM EDT this evening for NYZ081. NJ...None. MARINE...None. && $$ SYNOPSIS...PW NEAR TERM...Maloit/PW SHORT TERM...PW LONG TERM...JC/PW AVIATION...MD/Goodman MARINE...MD/Maloit HYDROLOGY...PW EQUIPMENT...

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