Area Forecast Discussion
Issued by NWS Upton, NY
Issued by NWS Upton, NY
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439 FXUS61 KOKX 250248 AFDOKX Area Forecast Discussion National Weather Service New York NY 948 PM EST Sun Nov 24 2024 .SYNOPSIS... High pressure will be in control through Monday. A cold front then approaches Monday night and passes through on Tuesday. Low pressure will likely impact the area during the end of the week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Forecast remains on track with only minor adjustments to account for the latest observations. Gusts are beginning to subside but still may linger for a few hours. The pressure gradient over the region continues to weaken this eve as low pressure over the Canadian Maritimes shifts east and a weak high pressure ridge moves in from the west. Leaned toward the warmer side of guidance for low temperatures, more so over coastal sections where a mixed boundary layer will have greater influence. Lows near 30 well inland to around 40 NYC metro. && .SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY/... High pressure ridge at the surface and aloft shifts into the area on Monday. Winds will be lighter from the west, and high temperatures will be near normal at 50-55. A longwave 500mb becomes negatively tilted as it moves across the Upper MS Valley/Great Lakes Monday night. This will strengthen a surface low that will track through Great Lakes and head into Southern Quebec during Tuesday. Models suggest that a secondary low center develops over us or southern New England on Tuesday. Rain begins to be possible after midnight Monday night ahead of an attendant warm front, but will be most likely during Tuesday as a trailing cold front passes through late morning/midday. Conditions should at least improve in the afternoon. High temperatures will still manage to climb above normal levels with the help of SW to W winds. Highs 55-60 for most spots. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... The main fcst challenge is the storm sys for the end of the week. High pres builds in S of the cwa for Wed. This produces fair wx with temps near normal and a wly component breeze. The NBM was used for most fields. The modeling does not produce a high confidence fcst thereafter. The 12Z ECMWF continues the idea of a fairly deep, organized low tracking thru the cwa on Thanksgiving. Depth is in the low 990s. This soln is very similar to the 00Z run, and a trend sewd from the 12Z run yesterday. The 12Z GFS has rebounded back to an offshore but close track with a weaker low, similar to many previous runs minus the outlying 00Z and 06Z runs. Incorporating the GFS persistence with the ECMWF trend, went with a colder than NBM fcst based off a track S of LI, with rain or snow for the nwrn interior and rain elsewhere. The MEX guidance was used for temps Thu-Fri, with the NBM too warm based on the conceptual model of the warm sector staying mainly S of the area. If the storm does end up further N, the temps will likely soar thru the 50s at the coasts and all areas will see rain until perhaps the very end when the low exits. A track S of the area with the right intensity could bring a snow event, particularly across the interior, so there is room to adjust either way with this fcst. Wind impacts are possible if the ECMWF track, timing and intensity verify. A strong sely flow Thanksgiving mrng into the aftn is possible if the low does track invof or N of NYC during that period. Pops are still in the fcst for Fri, although the 12Z runs suggest most of the pcpn will be over. Lowered the NBM numbers but did not eliminate altogether this far out. NBM pops were reduced to dry Sat-Sun however. The models may be picking up on too much ocean effect as a cold airmass builds in. There could be chances for some flurries or shsn at times, but probs/timing/coverage confidence all too low attm to include. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... High pressure slowly builds in from the west tonight as low pressure over the Canadian Maritime weakens and moves east into early Monday. The high builds over the region Monday. VFR. W to NW wind gusts have diminished a bit across the NYC metro area as high pressure builds slowly toward the area. Gusts will continue to subside through the overnight hours with most locations subsiding entirely by 6Z. A lighter, 10kt or less, WNW flow then continues into Monday. ...NY Metro (KEWR/KLGA/KJFK/KTEB)TAF Uncertainty... No unscheduled amendments expected. OUTLOOK FOR 03Z TUESDAY THROUGH FRIDAY... Monday night: VFR. Tuesday: Showers with MVFR, periods of IFR possible. Showers ending late in the afternoon into the evening, becoming VFR. SW winds gusting 20-25kt along the coast.. Wednesday: VFR. Thursday: MVFR/IFR with a chance of showers. Friday: VFR with a chance of showers. MVFR with rain and snow showers at KSWF. NW/W wind gusting 20-25kt. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... A SCA is in effect for all ocean zones through tonight, and might need to be extended a little into Monday morning east of Moriches Inlet. SCA remains elsewhere except for the Harbor. There could be some ocnl gusts to 25kt there so was included in the cwf. In addition, there`s a chance that gusts could still reach advisory criteria on eastern LI Sound and Peconic/Gardiners Bays for a fews hours after that advisory expires at 1 AM late tonight. High pressure and a weak pressure gradient will otherwise bring relatively tranquil conditions on all waters Monday and Monday night. Winds and seas then increase Tuesday with the passage of a cold front. Advisory thresholds will probably be reached on the ocean during Tuesday. Winds and seas blw sca lvls on Wed, then cond deteriorate on Thanksgiving as low pres impacts the waters. Gales possible into Fri, with sca cond likely on Sat. && .HYDROLOGY... No hydrologic impacts are expected through the weekend. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 1 AM EST Monday for ANZ331-332-335- 340-345. Small Craft Advisory until 6 AM EST Monday for ANZ350-353-355. && $$ SYNOPSIS...JMC/JC NEAR TERM...JC/MW SHORT TERM...JC LONG TERM...JMC AVIATION...MW MARINE...JMC/JC HYDROLOGY...JMC/JC