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Show Area Forecast Discussion - Jacksonville, FL (North Florida) Selection: |
| #1242548 (Received by flhurricane at: 2:33 AM 23.Aug.2025) AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 230 AM EDT Sat Aug 23 2025 ...FLOOD WATCH IN EFFECT TODAY... ...DANGEROUS RIP CURRENTS POSSIBLE AT AREA BEACHES TODAY... .NEAR TERM... (Today through Tonight) Issued at 230 AM EDT Sat Aug 23 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 The unsettled weather pattern continues today with the diffuse frontal boundary laying across southeast GA, with only a slight drift southward as a mean mid/upper level trough dips southward. Weak waves of low pressure may temporarily form along the wavy front, with one weak low pressure shown by the NAM and GFS to move along or just off the coast of GA and SC late tonight. Weak high pressure cell located off the coast of NY/NJ area will also move out to the east-northeast through tonight. The local airmass remains very moist with PWAT values of 2 to 2.3 inches, or about the 90th percentile. Mean layer flow is southwest about 10 kt, a little stronger than yesterday. This combination of high PWATS, boundary near-parallel sfc-6 km flow, and some divergence aloft suggests a heavy rainfall threat. In general, models are not too bullish on rainfall amounts, but some guidance shows localized 4-6 inches possible, with rainfall rates probably on the order of 2-3 inches/hour on soils that have received some moderate rainfall amounts over the past 3 days. Thus, have raised another flood watch for southeast GA counties and into part of northeast FL. Scattered to numerous showers and storms expected in the evening, but given the largely diurnal nature of the activity, expect most of the showers and storms to dissipate by 2-4 AM. Some patchy fog will be possible both this morning and again Sunday morning. Due to clouds and precip, highs today will be in the upper 80s to lower 90s again. Lows tonight in the lower to mid 70s. && .SHORT TERM... (Sunday through Monday night) Issued at 230 AM EDT Sat Aug 23 2025 A weakening frontal boundary draped generally over the FL/GA state border on Sunday gradually shifts southward into central FL on Monday and dissipates. Meanwhile, a mid-upper trough over the Great Lakes amplifies and digs southward pushing a dry cold front toward SE GA on Monday. On Sunday, lingering tropical moisture (PWATs 1.9-2.2 in) situated over the area will continue numerous to widespread showers and storms along and south of the stalled frontal boundary. WPC continues a Marginal risk of excessive rainfall across SE GA and NE FL on Sunday. Localized flooding will remain possible especially where storms train and in urban and low lying areas. Drier air begins to filter in from the northwest Monday afternoon in the wake of second front lowering rain chances over inland SE GA. Best rain chances on Monday will be over north- central FL along the dissipating frontal boundary. Stronger storms will be mainly focused along the frontal boundary, as well as the sea breeze and outflow interactions. Generally westerly flow will shift the Gulf sea breeze well inland each day and keep the Atlantic sea breeze pinned to the coast. Highs will range from the upper 80s to low 90s. Overnight lows will be in the 70s. && .LONG TERM... (Tuesday through Friday) Issued at 230 AM EDT Sat Aug 23 2025 Digging upper trough across the eastern CONUS will shift the cold front over NE FL on Tuesday down the FL peninsula through the week as high pressure builds into the region. Unseasonably cool, dry air settles into the area in the wake of the front on Tuesday scouring out the tropical airmass and potentially lowering PWATs to near 1 inch in SE GA. This will limit the rain chances to NE FL on Tuesday. Isolated to widely scattered showers and storms prevail through mid-week with the lingering drier air and high pressure remaining to the north. Moisture gradually increases across NE FL for the latter half of the week. Highs will generally be in the upper 80s to low 90s. The cooler, drier airmass may give the area its first taste of Fall with dewpoints falling into the low-mid 60s for inland SE GA and Suwannee Valley. && .AVIATION... (06Z TAFS) Issued at 230 AM EDT Sat Aug 23 2025 Some areas low clouds in the area with MVFR cigs and as usual VQQ has some occasional dense fog that is not present in other locations. The low clouds may become a bit more problematic in the next few hours, affecting the all TAFs except for SGJ. After the low cigs lift and any mist clears, VFR cigs and some MVFR cigs continue to be possible this morning, and then a high chance of showers and T`storms once again develop during the afternoon and continue into the evening hours. A period of MVFR and potential IFR vsby expected in the occasionally heavy showers and storms. && .MARINE... Issued at 230 AM EDT Sat Aug 23 2025 Frontal boundary will remain over the nrn marine zones today and then tend to drift south Sunday and Sunday night. Already have a few showers over the marine zones at this time due to the front. Winds will be light and sometimes variable today and expect another round of stronger showers and storms during the aftn and evening affecting area waters. A slight uptick in the offshore flow tonight as a weak low pressure system tries to form just north of the area along the frontal boundary. The front will stall over the area on Sunday, and then we see another reinforcing front begin to move in Monday and Monday night. This should allow the winds to turn more northerly next week by early Tuesday. The main story over area waters is the elevated seas, with the main component the easterly swells left over from Erin. Periods remain around 13-15 seconds. The guidance has a slight high bias currently, but not as much as a couple of days ago so only slight changes were needed in the forecast model wave heights. For this reason, have maintained an exercise caution in the offshore waters where there may be some 6 foot combined seas. This headline may need to be continued pending further guidance and any ship observations. Rip Currents: High risk rip currents is in place for northeast FL beaches and moderate for southeast GA. May need to enhance the risk again for Sunday pending further seas/surf forecasts. && .FIRE WEATHER... Issued at 200 AM EDT Sat Aug 23 2025 A weakening frontal boundary will stall near the GA/FL line through Sunday. This boundary will be a focus for showers and thunderstorms. The greatest chance for storms will be along and south of the front. Increasing moisture and the sea breezes interacting with the frontal boundary will increase storm coverage to numerous to widespread each day through the weekend. West-southwesterly flow will shift the Gulf sea breeze well inland and collide with a pinned Atlantic seabreeze near the Atlantic coast through the weekend. Increased cloud cover, lower mixing heights, and lower transport winds along the front will create low daytime dispersions over southeast Georgia today. The front will sink into central FL on Monday as another cold front moves into the area Monday night into Tuesday. Transport winds increase with the multiple frontal passages leading to good and potentially high dispersions for early next week. Drier air moving in behind the front will result in lower chances for storms next week. && .HYDROLOGY... Issued at 200 AM EDT Sat Aug 23 2025 Numerous to occasional widespread showers and storm will bring periods of heavy rainfall for much of the area today. The threat of the heavier rainfall is for southeast GA and southward into Nassau and Duval counties in northeast FL, which have seen some heavier activity in the past 24-48 hours. We have placed this area in a flood watch for today and into the evening hours. WPC has all of southeast GA and portions of northeast FL in a slight risk of excessive rainfall (i.e., scattered flash flood possible). It`s possible the watch could be a larger area, but for now the area captures the most likely areas for a flash flood situation due to the frontal boundary in that area. && .PRELIMINARY POINT TEMPS/POPS... AMG 85 71 87 70 / 80 40 40 10 SSI 86 74 86 75 / 70 60 60 30 JAX 89 73 89 73 / 80 40 70 20 SGJ 90 74 88 75 / 70 50 70 30 GNV 89 74 88 74 / 80 30 80 20 OCF 87 74 87 74 / 80 40 80 30 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...Flood Watch from 10 AM EDT this morning through late tonight for FLZ024-124-125-225-325-425. High Rip Current Risk through this evening for FLZ124-125-138- 233-333. GA...Flood Watch from 10 AM EDT this morning through late tonight for GAZ132>136-149-151>154-162-163-165-166-250-264-350-364. AM...None. && $$ |
