


Area Forecast Discussion
Issued by NWS Upton, NY
Issued by NWS Upton, NY
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901 FXUS61 KOKX 162330 AFDOKX Area Forecast Discussion National Weather Service New York NY 730 PM EDT Wed Jul 16 2025 .SYNOPSIS... Stalled frontal boundary dissipates across the region with otherwise low pressure well to the northwest through early Thursday. An associated cold front approaches Thursday and moves across Thursday night. Weak high pressure builds in thereafter for Friday. This high pressure area builds overhead Friday night and moves offshore Saturday. A frontal system will impact the region Saturday night and Sunday. High pressure builds to the north Monday. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Weak low level convergence and instability has led to a few showers in urban NE NJ and some thunderstorms just southwest of the area. This activity could continue into urban NE NJ before sunset, but should diminish with loss of heating. Otherwise, the next main chance of showers and thunderstorms late this evening into overnight associated with a mid level shortwave and increasing elevated instability. Blended in consensus MOS with NBM for lows to increase them slightly. These stay well into the 70s for much of the area. In addition, some patchy fog is expected to develop outside of NYC and may become locally dense. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY/... First, hazard of heat advisory ongoing. This will end 10PM Thursday evening. With the drier trend of model convection for Thursday afternoon, especially for locations farther east, feel that uncertainty grows with temperatures possibly being higher than forecast. Forecast sent out went above NBM by a degree for the entire area Thursday and 2 degrees above NBM Thursday for SE Suffolk, which may end up hardly receiving any rainfall for this next frontal event. Max heat indices for Eastern Suffolk in the 95-100 degree range with otherwise most other locations near 100 degree heat index Thursday. For Thursday, active convection expected in the morning with that mid level shortwave. Again, could have some gusty winds and torrential downpours with the thunderstorms. Some lingering morning fog can be expected, especially for eastern coastal locations. Locally dense fog will be possible. Some degree of organization is expected with the morning thunderstorms as low level jet is noted by forecast models to increase to near 20-30 kt. Helicity will be limited with low level winds stay from the south to southwest. So, main threat would be strong downbursts of wind. Then, after morning convection passes east of the region, there could be quite a lull in convective activity for the rest of the day. Models have trended less in convective coverage compared to previous forecast. Did not want to make significant changes just based on 12Z model run suite and still wanted to convey and keep the chance of showers and thunderstorms. With that being stated, did lower the POPs closer to 30 percent taking NBM and the previous forecast with equal weights. Lesser POPs for eastern coastal areas Thursday afternoon. Contributing to this decrease in model convection is weaker positive vorticity advection with some models even indicating negative vorticity advection in the afternoon. PWATs are also forecast to lower as well, going from nearly 2 to 2.2 inches early day to near 1.7 to 1.8 inches by late day. Winds are also forecast to increase as well with parent low deepening slightly as it travels just north of the US Canadian border Thursday into Thursday evening. 925mb flow stays near 20-25 kt through the day. This helps mitigate the flood threat but will keep a marginal severe threat for thunderstorms for strong downbursts of wind with these faster moving thunderstorms. Cold front moves across Thursday night with high pressure to follow for late Thursday night through Friday. Showers and thunderstorms possible early Thursday evening and then trending drier. Dry conditions forecast thereafter through Friday. The high pressure area late Thursday night into Friday will have its airmass in the Great Lakes. This will make a noticeable difference in terms of lower temperatures and dewpoints compared to previously. Thursday night, cooler temperatures expected with a range from the upper 60s to lower 70s for much of the area, and NYC staying more in the mid 70s. For Friday, warm temperatures for highs well into the 80s forecast but dewpoints will be more in the 60s. As a result, max heat indices are mostly in the upper 80s to lower 90s Friday, below heat advisory criteria. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... With the passage of a cold front early Friday, more seasonal temperatures, along with drier air, will be ushered into the region for Friday night into the beginning of next week. However, with surface high pressure moving offshore during Saturday, and the approach of a warm front, humidity levels will be slowly increasing, with dew points rising back into the mid 60s Saturday and into the lower 70s Sunday. With a frontal system passes near the region there will be a chance of showers and thunderstorms Saturday night and Sunday. A cold frontal passage Sunday night will bring somewhat drier air, with an east to southeast flow as high pressure builds to the north, and moves off the New England coast. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... A trough of low pressure remains nearby into Thursday. A cold front approaches Thursday evening. Mainly VFR with the exception of some brief MVFR this evening at KISP and IFR/LIFR at KGON tonight/early Thursday. Scattered showers are possible early this evening, mainly west of the NYC metro terminals. Additional showers and thunderstorms are possible late this evening into early Thursday morning with some local MVFR. Another round of showers/thunderstorms is possible late Thursday afternoon into the early evening. S-SE winds diminish this evening as they veer to the SW. SW winds increase after day break Thursday, becoming around 15 kt with gust 20-25 kt in the afternoon. Winds shift to the W Thursday evening once the cold front passes. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... SHRA/TSRA possible at the start of the TAF period until 02z, mainly at KEWR and KTEB. TSRA may end up just isolated during the PROB30 period tonight. Additional TSRA possible Thursday afternoon/evening. Start time of gusts Thursday may be off by 1-3 hours. .OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY... Thursday Night: Evening showers/storm possible, otherwise VFR. Friday and Saturday: Mainly VFR. Sunday: Chance of showers and tstms. MVFR or lower likely. Monday: VFR. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Through tonight, conditions are below SCA criteria with a weak pressure gradient in place. For Thursday and Thursday night, the pressure gradient increases and potentially there could be some SCA level wind gusts to 25 kt across parts of the ocean. For Thursday night, there could be enough fetch for some 5 ft seas as well on the ocean. It will be marginal for SCA conditions on the ocean and did not have enough confidence at this time to issue SCA for the ocean. Well below SCA for other waters. SCA potential relatively higher for ocean east of Fire Island Inlet. Also, the period of time SCA conditions could occur would be brief as forecast conditions for winds and seas lower on Friday with high pressure building in. Conditions remain below SCA thresholds Friday night through Monday night. && .HYDROLOGY... Localized flash flooding possible through early Thursday morning with high PWATs and less steering motion with thunderstorms. Less flooding threat Thursday into early Thursday evening as thunderstorms pick up in speed but minor flooding will still be possible. Hydrologic impacts are not expected thereafter through the middle of next week. && .TIDES/COASTAL FLOODING... With a strengthening southwest flow Thursday, the risk for rip current development will be moderate, and wave will be 2 to around 3 feet. A moderate rip current risk will continue into with the passage of a cold front early in the day, and winds from the northwest to west, and a southerly swell remains. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Air Quality Alert until 11 PM EDT this evening for CTZ005-009. Heat Advisory until 10 PM EDT Thursday for CTZ005>012. Air Quality Alert from 11 AM to 11 PM EDT Thursday for CTZ009- 010. NY...Air Quality Alert until 11 PM EDT this evening for NYZ069>075- 078>081-176>179. Heat Advisory until 10 PM EDT Thursday for NYZ067>075-078>081- 176>179. NJ...Air Quality Alert until 11 PM EDT this evening for NJZ002-004- 006-103>108. Heat Advisory until 10 PM EDT Thursday for NJZ002-004-006- 103>108. MARINE...None. && $$ SYNOPSIS...JM/MET NEAR TERM...JM SHORT TERM...JM LONG TERM...MET AVIATION...DS MARINE...JM/MET HYDROLOGY...JM/MET TIDES/COASTAL FLOODING...