


Area Forecast Discussion
Issued by NWS Upton, NY
Issued by NWS Upton, NY
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160 FXUS61 KOKX 170808 AFDOKX Area Forecast Discussion National Weather Service New York NY 408 AM EDT Tue Jun 17 2025 .SYNOPSIS... High pressure weakens further today and shifts to the east. A warm front approaches late tonight and moves through likely sometime early Wednesday. A cold front then moves through Thursday evening/night. High pressure builds in Friday, and generally dominates into the beginning of next week. A warm front will lift to the north and west of the region Saturday night into Sunday. && .NEAR TERM /THROUGH TONIGHT/... High pressure that has been nosing into northeastern portions of the area weakens further today and shifts east. The stalled frontal boundary that is well to our south will start to drift north as a warm front. No big change in heights aloft, we remain on the eastern periphery of a broad trough. Several weak embedded disturbances will pass overhead today into tonight. Plenty of cloud cover expected again today with rounds of scattered shower activity. Continues to be a difficult PoP forecast given weak lift. With the aforementioned disturbances aloft have more confidence in CAMs today and stuck close to this guidance. Temperatures overachieved Monday even with showers and cloud cover so stuck with NBM today given the similar flow. This gives highs in the upper 60s to low 70s. Also stuck with NBM for lows with thick cloud cover expected resulting in a lack of radiational cooling, 60s across the area. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... An active short term period is expected. A warm front moves through early Wednesday morning with a cold front following Thursday evening/night. The train of embedded upper level disturbances also continues. This pattern will result in several rounds of showers with potential for thunderstorms as well. Heavy showers and thunderstorms early Wednesday morning, mainly for NYC and north and west: Early Wednesday morning a warm front will push through and continue the surge of warm moist air into our area. Pwats increase to over 2 inches, which is near the daily record for the OKX upper air sounding. With the passing of the warm front the some CAMS show a shower/thunderstorm activity. Exact coverage is difficult to know at this point, but any shower or thunderstorm that does develop should be able to produce heavy downpours. CAPE is elevated but has a tall and skinny shape. It is worth noting that the GFS has stronger mid-level capping and is likely resulting in the lack of modeled QPF. Heavy showers and potential for strong thunderstorms Wednesday afternoon, mainly for areas west of eastern LI and eastern CT: With the area warm sectored we should be able to destabilize to about 1000 J/kg of MLCAPE or more in northeast NJ and the Lower Hudson Valley. A surface trough and shortwave aloft should be able to trigger some afternoon shower and thunderstorm activity. Decent instability but once again the profile is tall and skinny and shear is not too strong. This limits the severe threat and may be more of a heavy downpour threat, but some stronger cells could produce sub-severe wind gusts. Potential for severe thunderstorms Thursday evening: Thursday continues to be highlighted as a potential severe thunderstorm day by the CSU-MLP with a 15-30% chance of damaging wind gusts. The SPC has also outlined the area in a slight risk. The area is able to destabilize again ahead of an approaching cold front with guidance consensus around 1000 to 2000 J/kg of MLCAPE. The triggers for this event will be more focused and stronger than Wednesday given the falling heights aloft and cold front. The reason for severe potential comes from a more favorable CAPE profile and stronger shear than Wednesday. Aside from the shower and thunderstorm activity in the short term, the warming temperature trend will continue with temperatures in the upper 80s to lower 90s on Thursday. Did end up with slightly lower heat indices because Tds were lowered given the expected mixing and NBM high bias. Still have Tds in the upper 60s. && .LONG TERM /FRIDAY THROUGH MONDAY/... Key point: * Potential for high heat and humidity Sunday into early next week. Global models are in good agreement and forecast largely followed NBM during this period. In the wake of a cold frontal passage Thursday, high temperatures for Friday and Saturday will be a few degrees cooler than Thursday, and dew points will be much lower. Temperatures will be near normal to near 5 degrees above normal. With high pressure centered off the southeast coast Friday into the beginning of next week, heat and humidity will be building. Maintained slight chance probabilities across the region for Saturday night with the potential for showers and thunderstorms to move over the building ridge, and with a weak shortwave and a warm frontal passage to the northwest and north. The ridge and heights build Sunday into Monday, and the ridge remains into Tuesday. With NBM deterministic high temperatures Saturday into next week near the 25th percentile and the potential for higher temperatures, have blended in a small percentage of the 75th percentile, resulting in highs a couple of degrees above the NBM deterministic. The heat and humidity increase Sunday into Tuesday with temperatures 10 to 15 degrees above normal. There is the potential for reaching heat advisory criteria Sunday and Monday across northeastern New Jersey, the lower Hudson Valley, New York City, much of southern Connecticut and into northern Nassau and northwestern Suffolk counties. And a few places across northeastern New Jersey into the lower Hudson Valley may be near warning levels, however, this will depend on dew points in the upper 60s to lower 70s, which may mix out during the afternoon. && .AVIATION /08Z TUESDAY THROUGH SATURDAY/... High pressure off the New England gradually weakens and shifts east today as a stationary front remains well to the south. The front will begin lifting north as a warm front late tonight. IFR to LIFR prevails through the overnight and into this morning, and possibly into the afternoon, as any gradual improvement to MVFR will likely be during the afternoon. The improvement will be brief, and conditions are expected to lower once again to IFR and LIFR during this evening. Scattered light rain or drizzle will be possible through the overnight as another area of precipitation approaches northern New Jersey at 07Z. The chances for additional showers increases this evening, mainly north and west of the NYC metro. Winds will generally be E to NE 10kt or less through the overnight and into this morning. Winds then become ESE-SE late morning into the afternoon, and remain under 10kt. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Amendments expected for flight categories through Tuesday night. Timing of LIFR may be off by several hours overnight Thursday gets quite a bit more interesting with the cold front moving into the area during the afternoon and evening hours. Moderate to high instability and a strengthening vertical wind profile suggest the potential for strong to severe bowing line segments. SPC Day 4 and CSU-MLP have the area in greater than 15% for severe weather with the main threat being damaging winds. Limiting factors could be too much dry air in the low- levels, lowering MLCAPE values. However, it is a bit early to be too specific with details, but nevertheless something to keep a watch on. In addition, temperatures will be about 10 degrees above normal with dew points well into the 60s to around 70. NBM box and whisker plots show deterministic NBM at or below the 25th percentile. Thus, there is the potential for higher temps. Deterministic NBM similar to long rage GFS and ECMWF MOS values and could linger a few hours longer than indicated this morning. .OUTLOOK FOR 06Z WEDNESDAY THROUGH SATURDAY... Late Tuesday night: IFR-LIFR, in stratus and fog. Showers, mainly northwest. A chance of an isolated thunderstorm toward Wednesday morning. Wednesday: Chance of IFR early, then becoming MVFR during the afternoon. Brief VFR possible. Showers and thunderstorms likely with MVFR. Thursday: VFR. Showers and thunderstorms with MVFR possible in the afternoon and evening. A gusty thunderstorm possible across northeastern New Jersey into New York City. Friday and Saturday: VFR. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Winds and seas remain below Small Craft Advisory criteria through Wednesday night. A S/SW flow then increases and some 25 kt gusts are possible by Thursday afternoon. Especially nearshore gusts. Seas also likely increase to 4-5 ft across the ocean waters. With a strong SW to W flow in the wake of a cold front ocean seas will be near 5 feet Friday into Friday evening. Winds gradually diminish late Friday into Friday evening as high pressure builds toward the waters, and ocean seas fall below 5 feet by late Friday night. Winds and seas then remain below SCA levels Saturday into Saturday night. && .HYDROLOGY... Locally heavy downpours are possible with any showers/thunderstorms Wednesday morning, Wednesday afternoon and again Thursday afternoon into the evening. However, the risk of flooding will be mitigated by the speed of any cells and lack of overall cell training. No hydrologic impacts expected thereafter through the beginning of next week. && .TIDES/COASTAL FLOODING... Rip current risk remains moderate today and Wednesday with a continued E/SE 3ft 7s wave component and parallel/onshore flow. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...MET/JT NEAR TERM...JT SHORT TERM...JT LONG TERM...MET AVIATION...MET MARINE...MET/JT HYDROLOGY...MET/JT TIDES/COASTAL FLOODING...JT