Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 131948 AFDOKX Area Forecast Discussion National Weather Service New York NY 348 PM EDT Thu May 13 2021 .SYNOPSIS... High pressure continues to build in from the west tonight and remains in place through Friday night. It pushes offshore Saturday and remains over the western Atlantic through the middle of next week. Disturbances will move through from Saturday through Monday. A cold front will move through Tuesday night. High pressure builds in for Wednesday and Thursday. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Surface high pressure builds into the region. With a clear sky and decoupling winds overnight, good radiational cooling will occur. For low temperatures, used deterministic NBM for most areas, but went closer to the 10th percentile for areas that typically see stronger radiation. Lows in the Pine Barrens region are expected to drop into the upper 30s, and some of the northernmost zones should end up at around 40. Still a wide range of lows elsewhere with temperatures in the lower 40s to mid 50s. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... Heights rise on Friday as a shortwave shifts east from the TN/OH Valley region. High pressure will be the dominant surface feature, however some models show a weak trough setting up over the forecast area in the afternoon with some moisture convergence. Best lift will be with this trough/sea breezes and where CAPE will be able to build outside of the sea breeze influence. CAPE should be fairly low with dry low levels in place. The best combination of moisture and lift will be across the northernmost and westernmost zones in the afternoon, then including some areas farther south and east early in the evening. Will limit forecast shower/TSTM chances to isolated with this setup, especially since a mid- level cap will need to be overcome to enhance convective precip chances. High temperatures for most areas will be warmer than today`s, generally in the 70s. Dry conditions for the overnight after any convection winds down in the evening. Radiational cooling may still be factor late, but likely not as strong as will be tonight. && .LONG TERM /SATURDAY THROUGH THURSDAY/... The long term will be characterized by surface high pressure shifting off shore Saturday and remaining there through the middle of the week. During this time, surface troughs will move through Saturday through Monday. A cold front approaches from the northwest on Tuesday and moves through Tuesday night. Thereafter, high pressure builds in from eastern Canada through next Thursday. From Saturday through Monday, the surface troughs that move through will provide enough lift for showers to develop across the forecast area. Saturday and Sunday seem to have enough surface instability and steep enough lapse rates in the low to mid levels to warrant a mention of thunder. Monday, the lapse are not as steep, so did not mention thunder, though SBCAPE values are a few hundred J/kg across inland areas, so a passing thunderstorm is still possible. Nothing looks severe at this time. A cold front will approach late Tuesday and move through Tuesday night. This will continue a slight chance for showers for the tri- state. However, moisture is limited and much of the dynamics seem to pass north of the area. High pressure builds in thereafter from eastern Canada, providing dry conditions through next Thursday. Temperatures will be seasonably warm for the weekend thanks to the return southerly flow with the high off shore, except along the immediate shore. An increase in clouds on Monday will limit temperatures to the 60s, but they rebound to seasonably warm again for the rest of the week. && .AVIATION /20Z THURSDAY THROUGH TUESDAY/... High pressure dominates through the TAF period. A daytime trough is expected to develop later today. VFR conditions continue through the TAF period. South shore sea breezes will gradually shift winds southerly until sundown. Winds become light and variable once again tonight becoming northwesterly by early morning. Another round of sea breeze possible by Friday afternoon. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Timing of sea breeze could be 1-3 hours off from TAF. .OUTLOOK FOR 18Z FRIDAY THROUGH MONDAY... .Friday-Sunday...Mainly VFR. Isolated showers and/or thunderstorms each afternoon into early evening, mainly north and west of the NYC terminals. .Monday...Mainly VFR. Isolated showers. Isolated thunderstorms for the afternoon into early evening. .Tuesday...Mainly VFR. Detailed information, including hourly TAF wind component forecasts, can be found at: http:/ && .MARINE... With high pressure remaining over the forecast waters tonight through Friday night, winds and seas will remain below SCA levels. Lack of a strong pressure gradient will keep winds below 25 kt from Saturday through the middle of the week. Waves may to build 5 ft on the outer ocean waters Monday night. Otherwise, waves will remain below 5 ft. && .HYDROLOGY... No hydrologic impacts are expected through the forecast period. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...None. && $$ SYNOPSIS...JC/JP NEAR TERM...JC SHORT TERM...JC LONG TERM...JP AVIATION...DJ MARINE...JC/JP HYDROLOGY...JC/JP is the U.S. government's official web portal to all federal, state and local government web resources and services.