


Area Forecast Discussion
Issued by NWS Upton, NY
Issued by NWS Upton, NY
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137 FXUS61 KOKX 160819 AFDOKX Area Forecast Discussion National Weather Service New York NY 419 AM EDT Fri May 16 2025 .SYNOPSIS... Multiple surface troughs move through today and Saturday, followed by a cold frontal passage Saturday night. A secondary cold front moves through Sunday afternoon and Sunday night. Low pressure lingers in New England and into the Canadian Maritimes through Monday as high pressure pushes in. High pressure remains in control Tuesday into Tuesday night. Another frontal system impacts the area Wednesday into Thursday. && .NEAR TERM /THROUGH TONIGHT/... The upper level trough can now be seen to our east on latest satellite imagery. Heights may briefly rise aloft heading into the early morning hours. At the surface, a very weak pressure gradient is leading to calm to light winds. This and the moisture available from several days on onshore flow has resulted in fog around the area. With the fog being locally dense, have issued an SPS through 13z. The convection forecast today and Saturday continues to be very tricky. There will be multiple chances for showers and thunderstorms with different forcing mechanisms. The first chance will be with any activity that moves into our area this morning from the potential decaying MCS/broken line from the west. CAMs are not all that excited about this feature, but can not rule out some of this making it into far western portions of our area. Radar trends upstream will be monitored as this activity nears. Will have a better idea once, if at all, convection starts to enter western PA. As we head into the afternoon, shortwave energy approaches and instability increases as we warm to the upper 70s with mid 60s dewpoints. Some showers and thunderstorms likely spark just west and move towards the area. Highest chances are once again north and west of NYC, but can not rule out a shower or thunderstorm anywhere. Some organized convection is possible with this afternoon activity given increased instability and shear along with better curvature in the low levels on model hodographs. At this time the main hazard would be isolated damaging wind gusts or large hail, again mainly north and west of NYC. This activity will decrease heading into tonight. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... The upper level low continues approaching on Saturday with shortwave energy ejecting out ahead of it. Similar forecast challenges in the morning hours as there may be some sort of approaching convection left over from what happens in the Ohio Valley and Great Lakes region tonight. Then, once again, the area destabilizes ahead of a cold front. While CAMs are not overly excited about this either, there is potential for more widespread convection over the area Sunday afternoon given stronger forcing, instability(MLCAPE approaching 2000 J/kg) and shear(0-6km bulk shear around 40kt). This will also lead to more widespread chances of storms reaching severe thresholds. The SPC has placed the western half of the area in a slight risk. As of right now, the main threat is damaging wind gusts. Model hodographs will have to be watched as there is some indication of favorable low level shear and an isolated tornado can not be ruled out. Latest Nam3km and HRRR show around 150 m2/s2 of effective inflow layer SRH. The cold front moves through Saturday night and then a secondary cold front moves through Sunday and Sunday night. PoPs lower significantly, but there will be additional slight chances of showers across the interior Sunday afternoon with the upper low above us. && .LONG TERM /MONDAY THROUGH THURSDAY/... Mostly sunny skies take over as high pressure centered over or near Hudson Bay in Canada gradually noses into the area Monday into Tuesday night, keeping the area dry. To our northeast, low pressure will continue to exit into New England and into the Canadian Maritimes through. This will lead to breezy W/WNW winds from an increased pressure gradient through Monday. A frontal system from the Great Plains then moves into the Ohio or Tennessee River Valleys on Tuesday, moving through or in the vicinity of our region Wednesday into Thursday. Expecting showers during this timeframe. Too soon to call chances for thunderstorms. Model guidance still varies with timing, magnitude, and track of this frontal system. Have gone with chance POPs Wednesday into Thursday as a result. Temperatures look to cool each day in the long-term period, especially towards Wednesday and Thursday with clouds and rain limiting any heating. Highs on Monday will be in the upper 60s to lower 70s and by Thursday, with will be in the upper 50s to lower 60s. Overnight lows will range from the middle 40s to lower 50s. && .AVIATION /08Z FRIDAY THROUGH TUESDAY/... A surface trough approaches and moves through from the west today. Expecting IFR or lower through daybreak today. Improvement to MVFR this afternoon, but with potential showers. A passing thunderstorm is possible, mainly for the NYC terminals, but the chances for this are decreasing. Improvement to VFR for some terminals late in the day such as the metro terminals and KSWF. Conditions deteriorate once again for all terminals to IFR or lower tonight. Light and variable winds through daybreak becoming southerly at 10 kt or less for today and continue into tonight with outlying terminals becoming light and variable again. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Timing of IFR onset could be off by an hour or two for KTEB and KLGA. Timing of improving categories on Friday may also be off by an hour or two. .OUTLOOK FOR 06Z SATURDAY THROUGH TUESDAY... Friday night: IFR or lower. Saturday: IFR to start, improving to MVFR mid-morning, then becoming VFR in the afternoon with showers likely, and a chance of thunderstorms with MVFR. Sunday: Mainly VFR. Slight chance of showers inland. W winds G20- 25kt. Monday - Tuesday: VFR. Monday NW winds G20-25kt. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Dense fog on all waters is expected to continue through late morning. Fog will then return tonight, potentially becoming dense again. Winds and waves remain below SCA criteria through Sunday for the most part. There looks to be brief potential for 25 kt gusts Sunday afternoon, mainly for NY Harbor, western Sound and western Ocean. During this time, seas on the ocean could also approach 5 ft. Outside of this, there is potential for showers and thunderstorms each day, with potential for severe thunderstorms Saturday afternoon. Winds and seas will be locally higher in any storms. Winds are expected to remain below SCA criteria for Monday. However, there is a low to medium chance of 25 kt wind gusts over the ocean waters with low pressure over the Gulf of Maine creating an increased pressure gradient. Thereafter winds and waves should remain below SCA criteria due to lack of any strong pressure gradient across the waters. && .HYDROLOGY... There are no hydrologic concerns through the end of next week. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Dense Fog Advisory until 11 AM EDT this morning for ANZ331-332- 335-338-340-345-350-353-355. && $$ SYNOPSIS...JP/JT NEAR TERM...JT SHORT TERM...JT LONG TERM...JP AVIATION...JP MARINE...JP/JT HYDROLOGY...JP/JT