Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 270613 AFDOKX Area Forecast Discussion National Weather Service New York NY 213 AM EDT Mon Mar 27 2017 .SYNOPSIS... A warm front will approach overnight and then waver near the Tri-State region Monday into Monday night. Weak low pressure passes through on Tuesday followed by a cold front moving through during Tuesday night. High pressure then builds in for Wednesday and Thursday, and shifts offshore Thursday night. A low pressure system then potentially impacts the region Friday and Saturday. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Widespread drizzle and fog has overspread the NYC metro, LI, and the souther portions of the Lower Hudson Valley and will continue work across the remainder of the area through the overnight. Minor updates were made to account for latest observations. Isentropic lift is increasing from south to north over the area ahead of an approaching warm front. More widespread rain development expected across W/NW portions of the Tri-State late tonight into Mon Morning with approach of the shortwave energy aloft and 40-45kt llj overrunning a +2-3 stds PWAT airmass over an approaching warm front. Additionally...moistening easterly flow and a strengthening low- level flow ahead of the approaching warm front point towards an increasing probability for fog to become more widespread during the late night hours. Temps will run slightly above seasonable with cloud cover and onshore flow. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... Shortwave energy pivots through Northern NY into Northern New England on Monday...with surface warm front likely struggling to lift north of the area as low pressure weakens over Southern Ontario. With a weak wave development along the front...and a 45kt llj bringing in PWATS 2-3 stds above normal ahead of it...would expect a band of overrunning rain to work w to e across the area in the morning into early afternoon. The exact location of the warm front/surface low will determine where the heaviest overrunning rain axis will occur on Monday...with highest probs across interior closer to shortwave forcing. Stratus and fog are expected to hold tough to the north of the warm front in the morning...and possibly into the afternoon for parts of the area. There are some hints of weak elevated instability across NW zones Monday afternoon in the wake of the surface low as the shortwave energy is coming through. This should support some residual shower activity...and cant rule out an isolated tstm across NE NJ/Lower Hudson River Valley if warm front can work north. Temps forecast is tricky on Monday...conditional on warm frontal progress. Potential for temps to get into the lower 60s across NE NJ and surrounding if warm front moves north...while temps across interior CT could remain in the 40s if warm front hangs to the south. Coastal areas will likely see temps rise to around 50 degrees with onshore flow. Any rain/shower activity should taper off from w to e late Monday afternoon into early Monday Evening as the shortwave moves off to the east. The weak stationary front will likely hang near the region Monday night. With weak pressure gradient and abundant low-level moisture...stratus/fog are likely once again. Otherwise...region looks to be in between shortwaves...so not expecting much in the way of any organized rain activity. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... Models are coming into better agreement regarding a weak area of low pressure passing through or just south of the area Tuesday into Tuesday night. An associated warm front might push north into the southern zones, but with a lack of low level jet this time of the year, thinking is that the warm front won`t push through the entire area. Associated lift and moisture will however bring increasing chances of light rain as Tuesday progresses with best overall chances occurring during the late-day/evening hours and focused over the southern zones where best convergence and lift exist. A cold front quickly follows during the late night hours with additional chances of rain across the entire area. Temperatures through this period are expected to be above normal. High pressure builds in on Wednesday and shifts through the region Thursday into Thursday night. This period will be dry with above normal high temps on Wednesday as the strongest cold advection gets delayed until late in the day or evening. Thursday`s highs will be closer to normal. Models are also coming into better agreement regarding a late-week storm. Right now it appears that low pressure moving in from the west during Friday redevelops off the coast to our south on Saturday and heads out to sea into Saturday night. Rain would become increasingly possible as Friday progresses with a decent chance for rain Friday night and Saturday. There would also be a chance of mixed PCPN early Friday morning for some of the interior sections. Have PoPs capped at 50% for now with this being primarily a day 6-7 event. Weak high pressure returns for Sunday with dry weather and highs in the 50s. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... Low-level ridge gradually weakens overnight and gives way to an approaching warm front to the south. This front will lift slowly through during the late morning/early afternoon hours, possibly washing out across or just north of the area. Lower ceilings, drizzle, and fog continue to work in from the SW overnight. Conditions will continue to lower through the overnight with widespread LIFR before daybreak at most terminals based on current trends. IFR conditions could last through much of the period, especially to the north and east of the NYC terminals due to the uncertainty with the timing of the warm front. .OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY... .Monday night-Tue night...IFR likely, LIFR possible with rain/low clouds/fog. .Wednesday...VFR. NW winds G15-20KT. .Thursday...VFR. .Friday...Chance of rain with MVFR or lower conditions, especially late in the day and at night. E winds G20KT along the coast. && .MARINE... Marginal SCA gusts are expected on the ocean waters through tonight. The resultant easterly fetch should maintain ocean seas at 4 to 7 ft. Winds are expected to weaken and veer se/s on Monday as a warm front works into the waters...but e/se swells will likely keep seas at SCA levels into the evening. Ocean seas likely gradually fall just below SCA late Monday Night. Weak low pressure shifts through the waters on Tuesday, then a cold front moves through Tuesday night, followed by high pressure building in on Wednesday. Although the pressure gradient tightens as high pressure builds in, it appears that winds probably remain below 25 KT during this period. In spite of an offshore flow, a lingering swell is expected to keep seas up to 4 ft on the ocean waters into Thursday morning. A high pressure ridge then shifts through Thursday into Thursday night with tranquil conditions. An onshore flow then increases on Friday with the approach of low pressure. SCA conds will be possible on the ocean by late in the day. && .HYDROLOGY... Generally one quarter to one half of an inch of rainfall is expected through Monday...with locally higher amounts possible across the interior. No hydrologic concerns are anticipated with any periods of rain that occur within the rest of the forecast period. && .TIDES/COASTAL FLOODING... Latest surge guidance indicating that water levels will 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 2 AM EDT Tuesday for ANZ350-353-355. && $$ SYNOPSIS...JC/NV NEAR TERM...NV/DW SHORT TERM...NV LONG TERM...JC AVIATION...JE/DW MARINE...JC/NV HYDROLOGY...JC/NV TIDES/COASTAL FLOODING...

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