Area Forecast Discussion
Issued by NWS Jacksonville, FL
Issued by NWS Jacksonville, FL
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859 FXUS62 KJAX 040118 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 918 PM EDT Wed Jul 3 2024 ...New UPDATE... .UPDATE... Issued at 912 PM EDT Wed Jul 3 2024 For the latest NE FL and SE GA Daily Key Messages please visit: https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf Ongoing convection west of HWY 301 is finally starting to wind down, with some locally very heavy rainfall having occurred across some of these same areas this afternoon and evening. Flood advisories are set to expire at 930 and 1030 PM EDT respectfully over parts of Baker, Columbia, Union, Bradford, and Alachua Counties. A few showers have also popped up over Duval County from some localized convergence, but these showers should too fizzle in the next hour or so. && .NEAR TERM... Issued at 128 PM EDT Wed Jul 3 2024 For the latest NE FL and SE GA Daily Key Messages please visit: https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf Squeeze play between a trough just to our north, the Atlantic sea breeze and Gulf Sea Breeze front this afternoon and evening will lead to scattered to widespread convection over the spine of the FL peninsula and extreme SE GA. Convection is already popping and will be most significant in the Ocala-Gainesville to Lake City areas. Convection should die off between 10 p.m. and midnight. && .SHORT TERM...(Independence Day through Friday night) Broad surface high stretching across the western Atlantic, Florida and into the Gulf of Mexico will stay in place while ridging aloft centered over the Gulf, builds eastward and overhead through Friday. The overall diurnal convective regime will not change considerably between Thursday and Friday amid the stagnant flow pattern. Storm motion will be slow (<5mph) and driven almost entirely by the sea breeze and subsequent outflow interactions through the afternoon. The Atlantic sea breeze will "win out" each day, focusing the corridor of numerous showers and t`storms inland during the late afternoon and early evening hours. Convective coverage will be reduced along the coast by Friday as dry air aloft noses in from the Atlantic, but scattered to numerous showers storm are still expected inland, favoring the I-75 corridor. With deep moisture entrenched across the area, concerns with developing storms will be localized flooding due to hefty rainfall rates (3-5" per hour) and slow movement. The secondary hazard of concern will be strong outflow winds, around 30-50 mph, with a few storms. Though temperatures will be on par with climo for early July, the risk of heat-related illness will be higher given the holiday and potential for prolonged heat exposure. A "situational" heat advisory may be needed to highlight the risk and amplify messaging for the Independence Day holiday. Heat index values on the Fourth will range from 100-108 and increase toward Advisory levels Friday. && .LONG TERM...(Saturday through next Wednesday) Lingering subsidence beneath stout ridging aloft and a "drier" airmass hanging along the coast will reduce storm coverage a bit Saturday before another slug of deep moisture pooling ahead of a slowing front seeps in from the north. This moisture uptick will reinvigorate convection and numerous afternoon showers are expected beginning Sunday with PoPs of 50-70% each day through the middle of the week. Hot and humid conditions will remain above climo temps and heat index (average heat index is around 101F for JAX) through the period with heat headlines possible each day. && .AVIATION... (00Z TAFS) Issued at 713 PM EDT Wed Jul 3 2024 Convection remains ongoing as of 23Z for inland areas, including GNV where a TEMPO for TSRA and IFR vsbys is in the latest forecast through 01Z. Further east, VFR prevails with only some lower clouds on the cusp of MVFR for the next few hours. Can`t rule out MVFR briefly at any sites east of GNV, though next expecting any MVFR ceilings to prevail. Expecting FG/BR at VQQ overnight once again, and also cannot be ruled out at GNV given rainfall in that area today. Confidence not high enough to include this in the forecast at this time however. Sea breeze convection expected once again Thursday, with more specific timing and impacts to be nailed down in future forecast packages. && .MARINE... Prevailing winds have shifted to easterly as high pressure building over the Mid-Atlantic states wedges down the southeastern seaboard. Showers and thunderstorms will increase in coverage across our local waters along and south of a stalled frontal boundary through today. The frontal boundary will gradually slide southward dissipate over the local waters by Thursday, with prevailing onshore winds continuing as high pressure weakens off the eastern seaboard. Storm coverage will decrease Friday through Saturday, with prevailing winds then shifting to southwesterly during the weekend ahead of the next slowing frontal boundary approaching from the north. Rip Currents: Surf around 2-3 feet and onset of the Atlantic sea breeze will bring a Moderate risk of rip currents through Independence day. && .PRELIMINARY POINT TEMPS/POPS... AMG 74 94 74 95 / 20 30 10 40 SSI 79 90 79 91 / 10 20 0 20 JAX 76 93 75 95 / 20 50 10 40 SGJ 77 91 77 92 / 10 50 10 40 GNV 74 92 74 93 / 50 70 10 60 OCF 75 93 75 94 / 60 70 10 70 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$