351 FXUS62 KJAX 291346 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 946 AM EDT Mon Jun 29 2026 .KEY MESSAGES... For the latest NE FL and SE GA Daily Key Messages please visit: https:/www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf - Peak Heat Index Today 105-110 this Afternoon & Evening. Heat Advisory Northeast Florida & Portions of Southeast Georgia - Scattered to Numerous Coverage Coast shifting Inland into Evening. Strong to Marginal Severe Downbursts possible - Moderate Rip Current Risk Northeast FL Beaches Today - Minor River Flooding for Satilla River Continues && .UPDATE...through Tonight Took a hard look at the extent of the Heat Advisory with the morning update. Based on this morning's RAOB, there is a pocket of drier air in the low levels that will be mixed into by the post-frontal northwesterlies this afternoon. This effectively limits our peak heat index to around 105-110 with the higher values likely to occur at the coast where the sea breeze moisture spike will likely briefly pull heat index values around 108-110 degrees. However, given it being a seasonably hot day again have left the Heat Advisory footprint as is. With regards to convection, the tug of war between the "ridge rider" enhancement and the large upper ridge suppression - the ridge appears to be winning. Upper air observations indicate fairly warm mid levels and pockets of dry air above 850 mb, which will act to mitigate coverage this afternoon. HiRes convective models have caught up and have been indicating less coverage compared to 24 hours ago. However, the interaction of the NWrly flow and the sea breeze is still expected to spawn scattered thunderstorms this afternoon with outflow interactions dominating during the late afternoon and early evening. The main threat will be the outflow, especially early on in the afternoon as ambient air temps push into the mid/upper 90s. The aforementioned dry pockets aloft will support the potential for isolated strong to marginally severe wet microbursts (DCAPE close to 1,000 J/KG) capable of gusts up to 60 mph. For this evening there could be lingering convection across inland NE FL as outflows interact and siphon available buoyancy through around 10 PM. Additionally, showers and isolated storms may reach coastal SE GA areas this evening as the a second "backdoor" front pushes in from the NE. Some of the showers could hang on through midnight for SE GA but nothing significant is expected. && .SHORT TERM /THROUGH WEDNESDAY NIGHT/... Tuesday & Wednesday... Main Highlights This Period: - Breezy East Winds & Elevated Rip Current Risk - Inland Strong Afternoon & Evening Storms A transition to a stronger east coast sea breeze regime and drier conditions across southeast GA with the position of the 1000-500 mb ridge centered across TN/KY. This pattern will bring a chance of a a few spotty morning showers and early afternoon thunderstorms along the dominant east coast sea breeze as it shifts inland, with convection blossoming into the afternoon and evening across inland areas. Sea breeze and outflow boundary mergers will focus toward the I-75 corridor and westward each afternoon and into the evening. The highest rain chances focus across inland NE FL each day where deeper moisture lingers. Tuesday, a frontal zone combined with sea breeze forcing across inland northeast FL favors higher than climo rain chances, especially for locations west of Highway 301 toward the Interstate 75 corridor during the afternoon and evening. Below average precipitable water and mid/upper level subsidence across southeast GA invades Tuesday afternoon into Tuesday evening brining below average rain chances. Wednesday, the drier airmass continues to linger across locations generally near and north of the Interstate 10 corridor with a continuation of mostly dry weather across southeast GA with the higher daily shower and thunderstorm rain chances southward across inland north-central FL in the afternoon and evening. For all locales, Wednesday is trending drier than Tuesday with more abundant mid and upper level dry air in place. With the pattern shift of onshore, easterly winds, high temperatures will top out near 90 at the beaches and rise into the mid to upper 90s inland. With the drier air, dew pts mixing down into the low 70s to evening mid/upper 60s across parts of southeast GA will bring lower peak heat index values compared to recent days, generally in the 100-105 degF range, below local Heat Advisory criteria. && .LONG TERM /THURSDAY THROUGH SUNDAY/... Thursday through Sunday... Main Highlights This Period: - Higher Rain Chances Return for Northeast FL - Building Heat for Southeast GA Thu & Fri...The mean layer 1000-500 mb ridge dominates north to northeast of the region as a broad upper level low/trough approaches Florida from the east. This pattern will bring a continued easterly steering flow and a more dominant Atlantic/east coast sea breeze regime. Moisture and thus rain chances will be higher across northeast FL with the approaching upper level feature, and rainfall may not follow a typical sea breeze regime given upper level forcing and more abundant cloud cover with the passing upper level trough. Warmer temperatures and drier weather continues across southeast GA closer to the influence of the upper level ridge. Heat index values Friday near local Heat Advisory criteria (108-112 degF) across parts of NE FL. Sat & Sun...The upper level trough feature drifts farther westward while the upper ridge rebuilds and strengthens east to southeast of the southeast coast. This will transition prevailing winds from SSE to SSW into early next week, with deeper moisture expanding back northward across southeast GA. Local rain chances increase across all areas this weekend with active sea breezes brining afternoon and evening storms. For Independence Day, at this time, looks like the higher chances of thunderstorms will focus across northeast Florida during the afternoon, and then interior northeast FL during the evening with very weak storm motion...meaning that the rain and lightning threat could linger for a longer period of time where evening storms do form. A warming trend ensues into the weekend as well with highs pushing back into the mid to upper 90s with daily heat index values 105 deg, near but just shy of local heat advisory criteria. Tropical Outlook: There is a very low 10% chance of a low gaining tropical characteristics along a front offshore of the southeast Atlantic coast through mid-week. Later in the week, conditions become more unfavorable for development. There are no significant local impacts associated with this feature. && .AVIATION /12Z MONDAY THROUGH 12Z TUESDAY/... Northwesterly breezes, following the passage of a weak front overnight, will develop after 14z at around 5-12 knots. This front will enhance convergence along the Atlantic sea breeze this afternoon, with scattered showers developing around 16z-18z. Timing confidence is increasing with the best window for convection and associated impacts most likely between 18z-22z along the coast and 21z-02z at inland airfields along I-75, including KGNV. With convective impacts, the typical potential of gusty erratic winds, IFR to LIFR visibility, and brief periods of lower ceilings will be possible during the aforementioned windows. Area t'storms will fade this evening with VFR mid and high clouds lingering through the morning. Late in the period, there is a low chance for predawn showers moving in off the Atlantic at KSSI and possibly KCRG by daybreak Tuesday. && .MARINE... A frontal boundary will then approach the Georgia waters from the north tonight, with this boundary then stalling over the northeast Florida waters later on Tuesday and dissipating on Wednesday. Showers and thunderstorms will increase in coverage on today into tonight over our local waters, with activity then shifting from the waters adjacent to St. Augustine southward on Tuesday. High pressure wedging down the southeastern seaboard in the wake of this stalling frontal boundary will result in breezy northeasterly winds throughout our local waters on Tuesday and Wednesday, followed by onshore winds gradually diminishing later this week. Rip Currents: Lower surf heights today will drop the rip current risk to low at the southeast GA beaches, with a lower end moderate risk continuing at the northeast FL beaches. Persistent and breezy northeasterly winds on Tuesday should yield a solid moderate risk at all area beaches, with a potential high risk on Wednesday. && .FIRE WEATHER... - Areas Of High Daytime Dispersion Monday - Areas Of High Dispersion Across Se Ga Tuesday A weak surface trough will shift southeast across the area on Monday, accompanied by a wind shift to the northwest. The trough will interact with the sea breezes, resulting in numerous afternoon and evening showers and thunderstorms, with a few strong storms possible. By Tuesday, increasing northeasterly to easterly winds of 10 to 15 mph will shift the highest rain and thunderstorm chances westward toward the Interstate 75 corridor and the Florida Big Bend region. Increasing northwesterly transport winds on Monday may produce areas of high daytime dispersion across portions of the forecast area. Dispersions will remain high across Southeast Georgia on Tuesday. FOG POTENTIAL AND OTHER REMARKS: Significant fog is not expected during the next several days. Stronger storms will be capable of producing strong and erratic wind gusts, along with frequent lightning strikes and heavy downpours, especially on Tuesday afternoon and evening. && .HYDROLOGY... Minor flooding continues along lower portions of the Satilla River Basin, as water levels have crested in minor flood stage at the gauge near Atkinson. Minor flooding will continue during the next several days. && .PRELIMINARY POINT TEMPS/POPS... AMG 96 75 95 72 / 20 30 30 10 SSI 93 79 90 79 / 40 30 10 0 JAX 97 76 93 76 / 40 40 20 10 SGJ 95 77 92 77 / 30 30 20 10 GNV 97 75 95 73 / 30 40 60 10 OCF 96 76 93 75 / 40 30 80 20 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...Heat Advisory until 7 PM EDT this evening for FLZ021-023-024- 030-031-035-038-120-124-125-132-136>138-140-220-225-232- 233-236-237-240-322-325-333-340-422-425-433-522-533-633. GA...Heat Advisory until 7 PM EDT this evening for GAZ136-152>154- 162-163-165-166-264-350-364. MARINE...None. && $$