FXUS61 KOKX 181133 AFDOKX Area Forecast Discussion National Weather Service New York NY 733 AM EDT Sat Jul 18 2026 .WHAT HAS CHANGED... SPC has expanded the enhanced risk for severe thunderstorms north and east to include much of the Lower Hudson Valley, NE NJ, and NYC metro. && .KEY MESSAGES... 1) Scattered severe thunderstorms and flash flooding possible this afternoon into this evening. A Flood Watch remains in effect 10 AM this morning until 2 AM Sunday for NE NJ, NYC metro and Southern Westchester. 2) Areas of smoke expected this morning into the afternoon with reduced air quality and visibilities possible. Air quality alerts remain in effect from State DEPs until midnight. 2) Dangerous rip currents are expected at ocean beaches through this evening, potentially lingering at Suffolk beaches on Sunday. 3) Another round of showers and thunderstorms possible late Tuesday into a portion of Wednesday. && .DISCUSSION... .KEY MESSAGE 1... An upper level trough digs down into the Great Lakes Saturday and swings across eastern Canada and the northeast US Saturday night. Ahead of this feature, shortwave energy will pass across the area this afternoon as a warm front lifts north of the area into the afternoon. A pre-frontal trough will follow late in the afternoon with the main cold front moving across the area this evening with the potential of another line of showers/storms. Severe thunderstorms and potential flash flooding are the main concerns this afternoon and evening. It is important to note the exact location of the severe and flooding hazards may not become clear until a few hours before the onset due to the aforementioned uncertainties. PWATs are progged to reach between 2 and 2.25 inches, which is well above the observed 90th percentile per OKX RAOB climo. Freezing levels look to range from 13-15 kft with deep warm cloud layers, supporting efficient warm rain processes. These ingredients support the potential for heavy downpours in any convection this afternoon and evening. There is still some uncertainty with the amount destabilization today, especially with lingering smoke this morning and potentially apart of the afternoon (see key message 2 for more details on the smoke). The passage of the shortwave should allow the smoke to move away from the area in the afternoon. The greatest instability may set up just to our southwest, especially as the shortwave moves across the area. There should still be at least 1000-1500 J/kg of MUCAPE, but surface based CAPE could be limited this afternoon, unless greater destabilization occurs further north. The mid level flow is also fast enough to keep the convection moving across the area, which may limit the flooding potential. The latest HREF has a small area of 30 percent chance of greater than 3 inches in 3 hours just south of of our NE NJ and NYC metro zones. This is close to our flood watch and most susceptible areas for flash flooding, so no changes were made to the flood watch. Peak hourly rainfall rates of 1.5-2"/hour are possible. Isolated instances of flash flooding in some urban areas across the I-95 in S CT and potentially western LI are possible, but not enough confidence for an expansion of the watch at this time. WPC has maintained the slight risk for excessive rainfall. SPC has expanded the enhanced risk into much of the Lower Hudson Valley, NE NJ, and NYC metro with a slight risk remaining elsewhere. As noted above, there is uncertainty with the amount of destabilization due to smoke and potential of a round of convection as early as late morning and early-mid afternoon. The 00z HREF is indicated a mean SBCAPE of around 1000 J/kg across NE NJ into the NYC metro, but an ensemble maximum of upwards of 2000-3000 J/kg this afternoon for these areas. Elsewhere, the mean is around 500 J/kg with an ensemble max of 1500-2000 J/kg. The max surface CAPE values are possible if the smoke clears sooner and if the first round of convection is weak or moves out quicker. Bulk shear around 40 kt continues to be progged and there is low level directional shear/curvature in the wind profiles. The main threat from any severe storms will be damaging wind gusts. There is also a risk of a tornado, especially if the warm front lingers nearby, which would enhance low level helicity and shear. If we are able to get clearing and the first wave does not leave behind subsidence, then the potential line of storms with the cold front/pre-frontal trough could also contain a few severe thunderstorms. The cold front moves through the area around midnight, bringing an end to the threat of showers and thunderstorms. .KEY MESSAGE 2... Smoke is beginning to filter back into the area from the south early this morning as high pressure has moved offshore. HRRR, RAP, and RRFS smoke fields all show areas of smoke lingering across the area this morning and potentially into a portion of the afternoon. The smoke should begin to clear out and move to the east as a shortwave and showers/storms move across the area. There will be reduced air quality and visibilities into at least the early afternoon. NYDEP, NJDEP, and CTDEEP all have air quality alerts in effect until midnight. .KEY MESSAGE 3... Dangerous rip currents are expected at ocean beaches through this evening. A high rip current risk is in effect due to a strengthening southerly flow at 15 to 20 kt and SE swells. On Sunday, the high risk likely only continues for Suffolk County and during the morning hours. Guidance is showing a lingering 5 to 6 ft swell at 7s. .KEY MESSAGE 4... Guidance continues to be in good agreement on an amplified shortwave trough moving across the northeast Tuesday into Wednesday. The trough may then linger over the region through the end of the week. The next cold front will approach on Tuesday with increasing probabilities for another round of showers and thunderstorms late Tuesday into Tuesday night. CSU MLP is indicating a marginal risk for a severe thunderstorm and WPC has placed the area in a marginal risk for excessive rainfall. It is a bit too early for any specific severe or flooding impacts, but will continue monitoring trends over the next few days. Lingering showers may continue into a portion of Wednesday. High pressure should build into the northeast with mainly dry weather to end the week. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... High pressure will give way to an approaching frontal system today. A warm front will move across the terminals late this morning/early afternoon, followed by a cold frontal passage tonight. Then several rounds of showers and thunderstorms are expected to move through the area today with MVFR or lower conditions. Smoke has returned this morning bringing visibilities down to 2-4sm in NYC and even lower at some of the outlying terminals. The latest HRRR continues to show the greatest concentration between 12Z and 18Z, with improvement in the afternoon. Tonight, some MVFR or lower cigs will be possible for the first half of the night, with improvement back to VFR behind a cold front as drier air works in from the north. The only exception could be at KGON, where sub-VFR conditions could continue for much of the overnight period. SW/S winds increase to 10-15 kt with G20-25kt, with the highest across the eastern terminals. Low chance for SW LLWS below 2kft. Tonight, winds gradually become more westerly the northwesterly behind a cold front. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Amendments are likely today for 1- Any changes in smoke conditions from the wildfires in Canada and 2- timing of showers and thunderstorms associated with the frontal system moving across the area terminals. .OUTLOOK FOR 12Z SUNDAY THROUGH WEDNESDAY... Sunday and Monday: Mainly VFR. Tuesday and Wednesday: MVFR or lower with showers/tstms. && .MARINE... An SCA remains in effect into tonight for all waters except the NY Harbor and western LI Sound. Wind gusts should reach around 25 kt with seas building to around 5 ft on the ocean. 5 ft seas may linger on the ocean tonight into early Sunday, so the Advisory continues until noon on Sunday. Conditions are then quiet until the next cold frontal passage during the middle of next week. SCA conditions are possible Tuesday through Wednesday night, with the potential of 7 to 10 ft seas. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Air Quality Alert until midnight EDT tonight for CTZ005>012. NY...Air Quality Alert until midnight EDT tonight for NYZ067>075- 078>081-176>179. Flood Watch through late tonight for NYZ071>075-176-178. High Risk for Rip Currents through this evening for NYZ075-080-081- 178-179. NJ...Air Quality Alert until midnight EDT tonight for NJZ002-004- 006-103>108. Flood Watch through late tonight for NJZ002-004-006-103>108. MARINE...Small Craft Advisory from noon today to midnight EDT tonight for ANZ331-332-340-345. Small Craft Advisory from noon today to noon EDT Sunday for ANZ350-353-355. && $$ DISCUSSION...DS AVIATION...BC MARINE...DS