945
FXUS61 KOKX 311619
AFDOKX

Area Forecast Discussion
National Weather Service New York NY
1219 PM EDT Wed Jul 31 2024

.SYNOPSIS...
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A weak surface trough will linger over the area through the end of the week. A series of weak fronts will follow this weekend into early next week.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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A weak surface trough will linger over the region into tonight. Heat Advisory has been issued for much of NE NJ, NYC metro, and Nassau County through Thursday evening. Combination of temperatures around 90 and dew points in the lower to middle 70s should yield a heat index around 95 this afternoon, likely occurring again on Thursday. Ongoing convection across eastern LI will likely weaken as it continues moving NE towards New England early this afternoon. Starting to see scattered showers developing N and W of NYC metro, and coverage should increase the rest of the afternoon. Some thunderstorms are possible, but overall forcing and shear are weak limiting organization. A few locally heavy downpours are possible given PWATs around 2 inches. Highs should reach the middle and upper 80s for most with around 90 in the Advisory area. Heat indices generally in low 90s with around 95 in the Advisory. Cloud cover/convection could prevent readings from touching criteria this afternoon.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... Backside of trough tonight, with negative vorticity advection, drying out, clouds decrease. More ridging expected Thursday with more nearly steady height tendency thereafter through Friday before next shortwave trough approaches Friday night. This will bring potentially more coverage of showers and thunderstorms. For Thursday and Friday, more sun expected in the morning with the possibility of afternoon into early evening showers and thunderstorms. Thursday max temperatures forecast are in the low to mid 90s. For Friday, max temperatures more in the upper 80s to lower 90s, which are a few degrees cooler than previous forecast but dewpoints are forecast to be slightly higher than those of Thursday. Friday, showers and thunderstorms remain probable for a longer time through Friday night. 850mb temperatures trend a few degrees warmer, closer to 19 degrees C, compared to 850mb temperatures forecast for Wednesday. Expecting more widespread 95 to 100 degree heat indices both days. However with a relatively higher chance of showers and thunderstorms Friday, more uncertainty on Friday`s temperatures. Considering Wednesday`s mid 90s heat indices forecast, there is satisfaction of criteria for heat advisory for much of NE NJ, NYC and Nassau NY as heat indices forecast for Thursday for these locations will be around 100. Heat advisories may very well need to be extended into Friday with later forecasts but forecasts for Friday high temperature did trend a few degrees lower compared to previous forecast. So confidence at this time not high enough to extend heat advisory into Friday. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Key Points: * Multiple rounds of showers and thunderstorms possible each day into Monday. An active upper flow will be in place through much of the period, with the area on the southern fringe of the westerlies and several upper level disturbances moving through, which should bring diurnal convection each day through Monday. The best days for convection look to be Thu and again Sat/Sunday. Coverage may be more limited on Fri as any lead disturbances ahead of a closed low over the Ohio Valley will be moving through downstream shortwave ridging. The closed low is poised to affect the area through the weekend. Temps for the weekend may not be quite as warm but could be offset by higher dewpoints to yield 95+ heat index values in spots, especially NE NJ and in/around NYC. && .AVIATION /16Z WEDNESDAY THROUGH SUNDAY/... An upper level low will move into southern Canada. Meanwhile, a weak cold front approaches the area today. An improvement to VFR is expected over the next few hours. An area of spotty light showers has passed NYC terminals and may still have minor impacts to KHPN, KBDR, KISP, KGON, and KSWF through 17Z. VFR conditions are likely this afternoon until scattered showers and thunderstorms develop late afternoon - into the evening along a weak cold front. Showers may be more prevalent north of NYC and more isolated south of NYC. Thunderstorms are also possible with TEMPOs in all TAFs for this. S to SW winds 08-12 kt expected today. Some gusts can not be ruled out at the coastal terminals. Any gusts should reach about 20kt, but are currently only included in TAFs at KISP for a brief window. Winds become a bit more SW-W tonight, with winds falling below 10kt. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Amendments will be possible for timing of any precipitation today as well as timing any flight category changes. Occasional gusts to near 20 kt possible. OUTLOOK FOR 15Z THURSDAY THROUGH SUNDAY... Thursday: VFR. Friday-Sunday: Chance of MVFR or lower in afternoon/evening showers/tstms. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... An SCA is in effect for the ocean waters with building seas to around 5 ft and marginal gusts to 25 kt into this evening. Elevated seas continue into tonight. Otherwise, winds and seas will remain below SCA levels through Saturday with a relatively weak pressure gradient. Increasing/persistent S-SW flow may allow ocean seas to build to 5-6 ft late Sat night into Sunday. && .HYDROLOGY... Multiple rounds of showers and thunderstorms are possible through this weekend. While widespread flood impacts are not expected, localized urban and poor drainage flood impacts are possible. && .TIDES/COASTAL FLOODING... A high rip current risk continues into this evening with S flow 15 kt and incoming 5 ft/7-sec period swells. Winds diminish and turn more SW-W on daytime Thu, but still expect at least a moderate risk, possibly high into Thu morning, due to residual 3-ft swell. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...Heat Advisory until 8 PM EDT Thursday for NYZ072>075-176>179. High Risk for Rip Currents until 9 PM EDT this evening for NYZ075- 080-081-178-179. NJ...Heat Advisory until 8 PM EDT Thursday for NJZ004-006-103>108. MARINE...Small Craft Advisory until 6 AM EDT Thursday for ANZ350-353. Small Craft Advisory until midnight EDT tonight for ANZ355. && $$ SYNOPSIS...BG/JM NEAR TERM...JM/DS SHORT TERM...JM LONG TERM...BG/NV AVIATION...BC/BR MARINE...BG/JM HYDROLOGY...BG/JM TIDES/COASTAL FLOODING...