599 FXUS62 KJAX 221145 AFDJAXArea Forecast Discussion National Weather Service Jacksonville FL 745 AM EDT Mon Sep 22 2025
...New AVIATION...
.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
- High Rip Current Risk through Tuesday all Local Beaches
- Inland Heat Indices 100-105F Tuesday through Friday
- Daily Isolated Thunderstorm Risk Returns Today
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.NEAR TERM... Issued at 153 AM EDT Mon Sep 22 2025
Isolated showers over the offshore Georgia waters will further organize towards sunrise and spread scattered showers onshore from Mayport north along the SE GA coast as the coastal trough to the east shifts to shore through late morning. INcreased high level clouds near the coast will continue to fan north and east while some more breaks in the cloud cover will help low ceilings and fog, locally dense, forming inland well west of I-95 where winds will become near calm and drier air away from the coast allows temperatures stay in the 65-70 degree range.
High pressure will weaken to the NNE today with ENE winds 10-15 mph along the coast and 5-10 mph inland expected as showers push inland with widely scattered showers and T`storms during the afternoon proceeding westward with the Atlantic seabreeze traveling towards I-75 and US-441. A mix of low, middle, and high level clouds will keep mostly cloudy skies in the picture through the day. Highs will be in the mid 80s at the coast, upper 80s for most inland locations except for low 90s south of I-10 over NE FL and west of US-441 in SE GA.
Tonight, skies will become partly cloudy as high level clouds thin out with patchy fog developing away from the coast as winds inland weaken to near calm. Lows will be in the upper 60s inland along and north of I-10 and the low 70s over the SE GA coast and north central FL areas with low/mid 70s over the NE FL coast.
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.SHORT TERM... (Tuesday through Wednesday night) Issued at 153 AM EDT Mon Sep 22 2025
Daily rain chances from the Atlantic coast each morning to inland northeast Florida into the afternoon as sea breezes progress inland an interact with diurnal instability with elevated moisture across the area. Precipitable water rises above average into the 1.8 to 2 inch range which will fuel scattered showers and isolated mainly afternoon and evening storms that develop where boundary mergers occur. Weak storm motion (< 5 kts) will enable both sea breezes to press inland, with slow and erratic storm motion producing localized pockets of heavy rainfall. Tuesday, marginal bulk shear and some mid/upper level lift associated with a short wave trough could support a few stronger storms capable of gusty wet downbursts, mainly across northeast Florida. Wednesday, a short wave mid level ridge builds over the region which will limit thunderstorm coverage more compared to Tuesday, but a few afternoon and evening storms are possible inland where sea breezes merge. Rain chances rain of 20% or less were advertised along the coast by late morning to 30-50% across inland northeast Florida into the afternoon, with < 15% across southeast Georgia. Rainfall chances fade after sunset each evening inland with the loss of diurnal instability.
The main weather story will be building heat, with high temperatures warming into the low-mid 90s from inland to the beaches by Wednesday, nearing record highs. See climate section below for record information. Elevated dew points combined with the heat will create heat index values in the lower 100s inland to low-mid 90s at the beaches. At this time, heat index values are expected to remain below local heat advisory criteria (108F-112F). Overnight lows will also moderate into the low to mid 70s by Wednesday night, with a few upper 60s well inland.
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.LONG TERM... (Thursday through Sunday) Issued at 153 AM EDT Mon Sep 22 2025
Above normal heat and heat indices continue Thursday as southwest steering flow develops. Sea breezes will continue to trigger afternoon showers and storms, with increased rain chances across southeast Georgia with as deeper southwest flow lifts moisture farther north ahead of a deepening long wave trough across the eastern CONUS. Friday rain chances increase to 50-60% across the entire forecast area with deep moisture in place and the approaching long wave trough driving a surface front across the southeast region. Late Friday into Saturday, model consensus shows the surface front beginning to stall across the local area with the upper level trough only slowly edging eastward toward the Atlantic coast. This could continue elevated rain chances daily this weekend with the stalling front, but for now trended toward drier conditions across southeast Georgia and scattered showers/isolated storms across northeast Florida.
Temperatures will begin to trend cooler into the weekend with increased cloud cover/storminess, with highs in the 80s and lows in the 60s.
The tropical Atlantic is getting a little more active. There is a 30% chance of potential tropical cyclone formation in the 3-7 day time frame as a tropical wave approaching the Leeward Island today begins a northward turn later this week near the Bahamas. At this time, east coast troughing looks to keep this system offshore of the southeast Atlantic sea board based on ensemble model runs. Indirect marine and surf zone impacts are possible. Continue to monitor the latest forecasts at hurricanes.gov
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.AVIATION... (12Z TAFS) Issued at 745 AM EDT Mon Sep 22 2025
Patchy fog and low stratus should lift and dissipate in the next hour. Northeast winds around 5-10 kts prevail today with passing showers shifting onshore through the day. Best chances for showers are coastal and JAX metro sites. Coverage of T`storm not high enough for VCTS mention, but should be monitored with subsequent updates. Winds calm after 00Z with another chance for inland fog/stratus after 08Z.
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.MARINE... Issued at 153 AM EDT Mon Sep 22 2025
East northeasterly winds will continue today as high pressure to the north northeast begins to slowly retreat eastward while coastal troughing weakens this morning over the waters weakens and moves onshore bringing isolated to scattered coastal showers over the Southeast Georgia waters to the coast before sunrise. Tuesday, winds become more easterly and lighter as weak high pressure moves southward down the U.S. eastern seaboard. Wednesday into Thursday, high pressure will extend across south Florida as a surface front approaches from the west-northwest. Increasing showers expected Friday into Saturday as the front arrives into the area waters bringing elevated southerly winds and potentially exercise caution conditions.
Rip Currents: Expanded the high rip current risk to include Southeast Georgia Beaches in addition to Northeast Florida today into Tuesday due to increasing long wave periods with surf heights of 3-4 ft.
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.HYDROLOGY... Issued at 153 AM EDT Mon Sep 22 2025
Trends in the past 24 hours show portions of the St Johns river peak water levels rising well into action stage between 1.2-1.4 ft MHHW. Through at this time PETSS guidance is not showing a strong signal for Minor flooding which is exceeding 1.5 ft MHHW (above dry ground) today, so holding off on a Coastal Flood Advisory for this forecast. However, will continue to monitor observations and new guidance for a coastal flood advisory Tuesday or Wednesday over the lower St Johns river as light onshore flow continues preventing river drainage this week.
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.CLIMATE...
Daily record highs and high minimum temperatures for the next few days are below:
DATE 9/23 9/24 9/25 Normals
JAX 95/1925 94/2019 96/2019 High: 86 78/1933 78/1951 76/1930 Low: 69
CRG 91/2016 93/2019 95/2019 High: 85 79/2005 77/2017 76/1998 Low: 71
GNV 97/1925 95/1997 96/1931 High: 87 75/1933 75/1998 74/2010 Low: 68
AMG 94/2010 95/2019 98/1961 High: 86 76/2000 74/2000 74/1988 Low: 65
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.PRELIMINARY POINT TEMPS/POPS... AMG 88 68 92 68 / 30 10 10 0 SSI 84 72 86 72 / 30 10 20 0 JAX 88 71 91 72 / 40 10 30 0 SGJ 87 73 88 73 / 30 10 30 10 GNV 92 70 94 70 / 30 20 40 20 OCF 91 71 92 72 / 20 10 40 20
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.JAX WATCHES/WARNINGS/ADVISORIES... FL...High Rip Current Risk through Tuesday evening for FLZ124-125-138- 233-333.
GA...High Rip Current Risk through Tuesday evening for GAZ154-166.
AM...None. &&
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NWS JAX Office Area Forecast Discussion