Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 261847 AFDOKX Area Forecast Discussion National Weather Service New York NY 247 PM EDT Sun Mar 26 2017 .SYNOPSIS... High pressure centered over eastern Canada and extending into New England and the northeast will gradually slide east today. A stationary front well to the southwest will approach as a warm front tonight and move into the area Monday. Another frontal system affects the region Tuesday and Tuesday night. High pressure builds to the west Wednesday and Thursday. Another low pressure system approaches Friday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Center of Canadian high pressure gradually slides to the coast by late in the day. Temps will run a good 5 to 10 degrees below seasonable today with cold air damming and cloud cover. Max and hourly temp trends have been adjusted down slightly. A swath of light rain over SE CT will push east by mid afternoon, coincident with an elevated warm front and corresponding zone of positive theta-e advection. The threat for icing has ended. Some spotty light rain activity possible across the region this afternoon associated with some weak vort energy...but overall coverage and probabilities look slight under shortwave ridge axis.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/... The closed and nearly cut off low that was over Missouri will continue to open and weaken as the shortwave gets picked up by a weak southern stream flow, and the wave moves into the eastern ridge. There remains some timing difference with the movement of the warm front and low tonight into Monday. Also, with weak forcing unsure how much precipitation will occur. So have lowered probabilities into the likely category, with the higher chance west and north late tonight into Monday. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... With the wave continuing to dampen late Monday into Monday night with weak ridging ahead of the next shortwave, there may be a break in the precipitation. However, with the uncertainty, and to keep continuity have continued with slight chance probabilities Monday night. Yet another shortwave approaches in the weak southern stream as this wave also dampens as wave approaches the mid Atlantic. There are timing differences and whether or not the shortwave will phase with a digging northern stream shortwave Tuesday. With uncertainties will keep probabilities at low chance Tuesday into Tuesday night. Wednesday and Thursday look to be dry with high pressure building in. Cold air advection appears to be delayed enough to the point where highs on Wednesday end up above normal, then near-normal for Thursday. Friday could be completely dry as well, but perhaps some rainfall sneaks into the western zones by the end of the day. High temps again near normal. Global models then disagree with the track of an area of low pressure that could bring rainfall on Saturday. Have capped PoPs at 40% for now. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/...
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High pressure over the area this afternoon will weaken and move northeast tonight as a warm front approaches. This front will then lift slowly through during Monday morning. Drier air making a westward push into the NYC metros should raise ceilings into the VFR category until after sunset. Then expect conditions to gradually lower through MVFR to IFR this evening, and then LIFR toward daybreak. The timing for these worsening conditions will be later farther north/east, and may not occur until well after midnight at KSWF/KBDR/KGON. Timing of warm frontal passage, with accompanying wind shift to S and subsequent improvement of ceilings is uncertain. The front is more likely to lift through later rather than sooner, which would delay onset of forecast improvement--in that case IFR conditions could last through the end of the TAF period, with wind direction remaining more E-SE rather than S. .OUTLOOK FOR 18Z MONDAY THROUGH THURSDAY... .Monday...Gradual improvement in flight category, though MVFR may hang on into the afternoon especially NE of the NYC metro terminals, and IFR at KGON. .Monday night-Tue night...IFR likely, LIFR possible with rain/low clouds/fog. .Wednesday...VFR. NW winds G20KT. .Thursday...VFR. .Friday...Chance of rain with MVFR or lower conditions, especially at night. E winds G20KT along the coast.
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&& .MARINE... Marginal easterly SCA gusts are expected on the ocean waters through tonight. The resultant easterly fetch will allow for ocean seas to build to 4 to 7 ft. Winds are expected to weaken and veer se on Monday as a warm front works into the waters...but e/se swells will likely keep seas at SCA levels through the evening. Otherwise, sub-sca conditions are expected across all waters briefly on Tuesday before gradually building through the evening in strengthening southerly flow ahead of a low pressure approaching from the west. Strong west-northwesterly flow with gusts to 25 kt will develop on Wednesday as a cold front passes which will initially allow seas to stay elevated at SCA levels before gradually shifting east of the ocean waters. Stronger winds may persist into Thursday before weakening by late week as high pressure briefly builds over the area. && .HYDROLOGY... One quarter of an inch to one half an inch of rainfall is possible today through Tuesday night. No hydrologic issues are anticipated through Tuesday. && .TIDES/COASTAL FLOODING... Latest surge guidance indicating that water levels should stay safely below minor flood thresholds for tonight and Monday Morning high tide. As astronomical tides rise through the week...water levels may come close to minor levels during high tides in the most vulnerable spots on Tue/Tue Night ahead of approaching low pressure. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 7 PM EDT Monday for ANZ350-353-355. && $$ SYNOPSIS...MET NEAR TERM...MET/NV SHORT TERM...MET LONG TERM...JC/MET AVIATION...Goodman MARINE...MD HYDROLOGY...MET TIDES/COASTAL FLOODING...

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