FXUS62 Area Forecast Discussion Northeast Florida

FXUS62 KJAX 040612 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 212 AM EDT Fri Jul 4 2025 ...New NEAR TERM, SHORT TERM, LONG TERM, AVIATION, MARINE... .NEAR TERM... Issued at 207 AM EDT Fri Jul 4 2025 For the latest NE FL and SE GA Daily Key Messages please visit: https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf Synopsis...A surface front was stalling near the FL-GA state-line early this morning with some moisture pooling near and south of the front developing low stratus and occasional fog. A broad surface low was observed in satellite early this morning, about 100 NM east of the First Coast. In the upper levels, a broad trough was slowly carving southward across the eastern CONUS while mean layer 1000-500 mb steering flow was weak from the NNE less than 10 kts with streamlines showing a broad cyclonic flow near and just east of the FL peninsula. Satellite derived precipitable water (PWAT) was over 2 inches across NE FL and coastal SE GA, while a sliver of lower than average PWAT < 1.7" was across our far NW GA zones near the Altamaha and Ocmulgee River Basins (daily median PWAT for this date is 1.75 inches). Forecast...Showers and isolated storms will break out late morning across coastal SE GA and across portions of NE FL generally south of the I-10 corridor near and south of the lingering frontal zones as onshore ENE winds develop a stronger east coast sea breeze. Convection will blossom as the east coast sea breeze shifts inland across SE GA, especially for locations ESE of a Jesup to Waycross to Homerville line and across much of NE FL where deeper moisture (PWAT 1.9-2.2 inches) lingers while drier air toward the Ocmulgee River basin brings more isolated to scattered afternoon showers and storms. The higher rain chances of 60-80% will focus across NE FL this afternoon into the early evening, especially for locations along and south of the I-10 corridor where boundary mergers occur under increasing NNE steering flow of 10-15 kts. As has been the case, the main convective concern will be localized heavy rainfall which could bring brief flooding as well as gusty downburst winds in merging cells given weak shear, warm temps aloft and weak lapse rates. Rainfall will generally tapper off across inland areas this evening through midnight, while coastal showers and isolated storms increase over the adjacent coastal waters and could skirt near the coastal counties through daybreak Saturday morning as the coastal low farther offshore further develops. Temperatures will trend from the upper 80s at the coast to lower 90s well inland, near to slightly below average values. Muggy and mild overnight lows will range in the low to mid 70s inland to upper 70s coast. && .SHORT TERM... (Saturday through Sunday night) Issued at 207 AM EDT Fri Jul 4 2025 Moist low pressure air mass is anticipated to be over and near the forecast area, situated ahead of the stalled frontal boundary for the start of this weekend, leading to widespread showers and storms forming during daytime hours through the period with intensity and dispersion depending on the positioning of the air mass and upper level shortwaves passing through the region. High temperatures this weekend will rise into the upper 80s and lower 90s with overnight low temperatures dropping down into the lower 70s over inland areas and in the mid 70s along the coastline. && .LONG TERM... (Monday through Thursday) Issued at 207 AM EDT Fri Jul 4 2025 Pattern for diurnal showers on storms is expected to carry over into next week with convection developing in association with sea breeze boundaries and areas of convergence, however the timing and placement of the potential low pressure cyclonic system forming ahead of the decaying frontal boundary still carries some uncertainty with the NHC forecast currently showing a 60% chance for formation by the end of the week, with a 40% of formation by the beginning of the week. Daytime high temperatures will be slightly above average with temperatures expected to be in the low to mid 90s. && .AVIATION... (06Z TAFS) Issued at 207 AM EDT Fri Jul 4 2025 Low stratus with LIFR to MVFR restrictions was developing early this morning and could impact terminals through daybreak, then low stratus lifts into a MVFR cumulus field through 13-14z under light NNE winds < 6 kts. After 15-16z, coastal shower chances increase at SSI then CRG, JAX and SGJ with TS through 18-19z and continued with PROB30 as NE winds increase to 10-12 kts with gusts near 20 kts into the afternoon. Best for TS this afternoon focuses at VQQ and then GNV 19-24z where VCTS will be included in the FM groups and TEMPOs added later based on radar trends. After sunset, precipitation tappers off inland with a low < 20% chance of coastal showers mainly after 06z Saturday with MVFR ceiling potential. && .MARINE... Issued at 207 AM EDT Fri Jul 4 2025 A front will stall and linger over the local coastal waters today through the weekend. An area of weak low pressure will develop along the frontal boundary late tonight or Saturday, and the low is expected to meander over the coastal waters through Sunday. Elevated winds and seas could reach Small Craft Advisory conditions mainly across Georgia waters this weekend. The low is expected to lift northward away from the local waters late Sunday or Monday. The National Hurricane Center is monitoring this system to see if the low will become a tropical or subtropical depression. As the low departs Monday into Tuesday, a weak trough will linger across Georgia as high pressure builds northward across the Florida peninsula. Rip Currents: A moderate rip current risk is expected through the holiday weekend with a low high risk possible for SE GA beaches Saturday if the coastal low approaches the local coast. Elevated surf will generally be 2-3 ft with 3-4 ft breakers possible along the SE GA Saturday. && .PRELIMINARY POINT TEMPS/POPS... AMG 92 72 88 71 / 30 10 70 20 SSI 87 76 85 75 / 40 30 80 30 JAX 90 74 88 73 / 60 30 90 30 SGJ 88 74 87 73 / 60 30 90 30 GNV 92 72 90 71 / 70 20 90 20 OCF 91 73 88 73 / 80 30 90 30 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$