FXUS61 KOKX 040007 AFDOKX Area Forecast Discussion National Weather Service New York NY 807 PM EDT Tue Aug 3 2021 .SYNOPSIS... High pressure will remain over the northeast through Wednesday morning. A frontal boundary south and east of the area will gradually draw closer Wednesday afternoon through Thursday before weakening Thursday night. The frontal boundary starts to move offshore Friday as weak high pressure southwest of the region assumes control. This high pressure area will more or less remain in control through the weekend and into the first half of next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... Forecast remains on track. For this update adjusted hourly database to better align with observations and trends. Previous discussion follows. For tonight, upper level trough approaches from the west and the upper level ridge out in the Atlantic remains anchored without much movement. At the surface, high pressure will build in from the north and west, but mid and high clouds will still be expected to be abundant as they continue to move northward from the front offshore. The front will be slightly retrograding back west but showers are expected to remain offshore. The abundant clouds will keep temperatures up. Min temperatures were a consensus of all model data, mostly in the low to mid 60s. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY/... For Wednesday through Thursday, upper level trough and upper level ridge do not move much. The trough will have multiple embedded shortwaves along it, the more amplified one moving across Wednesday night with more focused positive vorticity advection and a weaker one for Thursday with less positive vorticity advection. The most instability and forcing will be moving across Wednesday night into early Thursday. At the surface, high pressure to the north and west weakens and gives way to retrograding front moving westward from offshore. A wave of low pressure moves along the front and approaches the region Wednesday night, moving across eastern sections very early Thursday. The wave of low pressure and front will continue to make their way northeastward on Thursday. Rain showers move in for eastern sections potentially for Wednesday afternoon and likely for Wednesday night and into Thursday morning. Highest POPs are for the eastern half of the forecast region as are the rain amounts as well. Rain showers end from west to east on Thursday. There is apparent forcing seen in the upper jet level and that is the local region being in the right rear quad of the upper level jet Wednesday night into early Thursday. Layer PW values are in the 1.7 to 2 inch range for eastern sections in line of path with the wave of low pressure. Heavy rain showers are in the forecast for eastern sections of the region. See hydrology section for more details. In addition to the heavy rain showers, models are indicating some elevated instability with the wave of low pressure especially for eastern sections, so have isolated thunderstorms as well mentioned for Wednesday night. The main uncertainty is with the axis of heavy rain showers. This has fluctuated with different models and model runs and latest trends are showing the westward trend of this heavy rain shower area with the westward trend of the front. Temperatures are going to exhibit a minimal diurnal trend Wednesday into Wednesday night. Expansive clouds and increasing onshore flow on Wednesday will have highs only in the mid to upper 70s. Then, the rain showers Wednesday night will keep lows in the low to mid 60s. Eastern sections stay in the mid to upper 70s for highs Thursday while locations farther west for NYC, Northeast NJ, SW CT, and Lower Hudson Valley get into upper 70s to lower 80s where rain showers are expected to end earlier and clouds will decrease more. && .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/... Dry conditions are expected on Friday as weak high pressure from the west will begin to assume control of our weather. Other than Saturday, heights will overall gradually begin to rise. Thus, warmer temperatures are expected into the weekend. On Saturday weak high pressure will remain just to the southwest, while a shortwave will attempt to approach the area late in the day and at night, resulting in the chance to slight chance of afternoon showers and thunderstorms, with the slightly higher chance across northern and northwestern most zones. Towards Sunday night and early Monday a warm front may get close to the area from the west. Have chosen to introduce a slight chance of thunderstorms for this period. Afterwards, continuing to keep some low chance to slight chance pops in the forecast Sunday and Monday as diurnally driven storms will be possible with a warm and humid airmass in place. Highs in the long term will be well into the 80s, to around 90 in the metro areas. A southerly flow should usher in higher dew points into the first half of next week. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... A weak low passes east of the area tonight. Another low approaches late Wed. VFR through at least 02Z Thursday is expected. MVFR ceilings move in thereafter for KJFK and KLGA. Chances for MVFR ceilings decrease for KEWR and KTEB as they will be farther from the low, however there is a fair amount of uncertainty in the forecast. Some -RA after 16Z, but the probability is too low to include in the TAFs at this time. However, the rain should be light enough to have no impact to visibility. Light and variable winds through tonight. Flow pattern is complicated for Wed with lows offshore, but winds are expected to range from 080-140 with speeds generally at or above 10 kt. NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... No unscheduled amendments expected. .OUTLOOK FOR 00Z THURSDAY THROUGH SUNDAY... .Wed night...IFR with +RA possible overnight. .Thu-Fri...VFR. .Sat-Sun...Mainly VFR. Chance of afternoon showers and thunderstorms. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Conditions initially will be below SCA thresholds through Wednesday morning and the early to mid part of Wednesday afternoon. Then, the pressure gradient increases with increasing winds and seas late Wednesday afternoon into Wednesday night with the wave of low pressure approaching along the front. SCA is in effect from 4PM Wednesday until 6AM Thursday for the ocean. Higher ocean seas at SCA levels are forecast to linger Thursday but confidence in this part of the forecast is low so SCA ends at 6AM Thursday at the moment. Otherwise, sub-SCA conditions are expected outside of the ocean for the short term period and with wind gusts for Thursday. Small craft seas are likely Thursday night on the ocean. Seas should then subside below small craft towards Friday morning for the western ocean zones. By Friday afternoon sub small craft conditions will also become increasingly likely on the eastern ocean zones. The rest of the period should experience sub SCA conditions throughout all waters. && .HYDROLOGY... Basin averaged rainfall mainly near 0.25 to 0.75 inches are forecast Wednesday afternoon through Thursday, falling mainly Wednesday night into Thursday morning. Locally higher amounts of rain are expected, especially for eastern half of the hydrologic service area such as Eastern Long Island and Southeast Connecticut. These higher amounts of rain could be in the 1 to 2 inch range under any heavier bands of showers and possibly between 2 and 3 inches. These heavy bands of showers could result in minor flooding in any poor drainage and low lying areas with a marginal risk of flash flooding. && .TIDES/COASTAL FLOODING... There is a moderate risk for the development of rip currents at the ocean beaches Tuesday. A moderate risk for western ocean beaches remains in place for Wednesday, with a high risk across eastern ocean beaches on Wednesday. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory from 4 PM Wednesday to 6 AM EDT Thursday for ANZ350-353-355. && $$ SYNOPSIS...JE/JM NEAR TERM...JE/JM SHORT TERM...JM LONG TERM...JE AVIATION...JP MARINE...JE/JM HYDROLOGY...JE/JM TIDES/COASTAL FLOODING...JE