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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

- Isolated TStorms Across North Central FL this Afternoon & Evening

- Marine & Coastal Hazards this Weekend and Next Week. Dangerous Surf Zone Conditions - High Risk for Rip Currents & Rough, High Surf. Wind Gusts of 30-40 mph at Coastal Locations from Saturday through Monday. Gale Watch for All Atlantic Coastal Waters from Saturday through Monday. Minor Tidal Flooding Along the Atlantic Coast, ICWW & St. Johns River Basin. Significant Beach Erosion Possible at Area Beaches During Times of High Tide

NEAR TERM /UNTIL 7 AM SATURDAY MORNING/

Main Highlights:

Afternoon surface analysis depicts a strong cold front extending from New England southward through the southern Appalachians and the lower Mississippi River Valley. Meanwhile, impressively strong high pressure (1046 millibars) for mid-October was building eastward from the Rockies towards the Plains states in the wake of this strong cold front. Aloft...stout ridging centered east of the Bahamas was extending its axis westward to our area, downstream of a potent trough that was digging southeastward from the Upper Midwest and Great Lakes region towards the Ohio and Tennessee Valleys. Latest GOES-East derived Total Precipitable Water imagery indicates that a seasonably dry air mass was lingering across southeast GA, where PWATs were generally around 1.25 inches. Otherwise, deeper moisture was gradually advecting northward from the FL peninsula ahead of the approaching front, with PWATs climbing to near or just above 1.75 inches across north central FL, while values elsewhere were slowly approaching 1.5 inches. A healthy cumulus field has developed across our area as moisture levels gradually increase, but shower development thus far remains just south of our area in Volusia County (along the developing Atlantic sea breeze boundary), with convection otherwise confined to the Gulf waters adjacent to FL's Nature coast, as well as the Gulf Stream waters adjacent to east central FL. Temperatures at 18Z have generally climbed to the mid and upper 80s, with dewpoints ranging from the low and mid 60s across inland southeast GA and the Suwannee Valley to the low and mid 70s along the northeast FL coast.

Enough moisture will advect across north central FL later this afternoon and early this evening for isolated to widely scattered showers and a few embedded thunderstorms to develop, mainly for locations around Lake George and Crescent Lake, with measurable rainfall chances generally confined to areas south of a line from Gainesville to Palatka to St. Augustine. Any showers or isolated storms that develop across north central FL should dissipate before the mid-evening hours, followed by increasing multi-layered cloud cover overnight.

Potent troughing aloft will dig into the southeastern states tonight, driving a strong cold front across southeast GA and Suwannee Valley during the overnight and predawn hours, with this front crossing north central and coastal northeast FL towards sunrise. A few showers or light sprinkles will be possible along or just behind the frontal boundary, with winds abruptly shifting to northwesterly during the predawn hours and becoming gusty from north to south towards sunrise. Lower stratus cloud cover will also overspread our region during the predawn and early morning hours on Saturday, and late arriving cold air advection will drop lows to around 60 for locations north of Waycross in southeast GA, ranging to the lower 70s for north central and coastal northeast FL.

SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/

Main Highlights This Period:

- Strengthening Northerly Winds Tonight: Gusts to around 30-40 mph expected on Saturday through Sunday. Strongest gusts mainly for the coastal areas.

- Coastal & Marine Hazards Increase This Weekend

Strong frontal boundary will likely have already cleared our area by Saturday Morning, as cool and dry high pressure ridging quickly builds in from the west, ushering in both the coolest and driest airmass of the fall season so far. This airmass will also feature windy northerly conditions Saturday that will transition towards more of a northeasterly wind event on Sunday. Not expecting much in the way of rainfall/convection with the frontal passage, though Hi- Res guidance is highlighting at least some isolated shower potential Saturday over southern areas, mainly during the morning hours.

The main difference with this event compared to the previous onshore flow event will be the strength of the presssure gradient and therefore expected winds, as low pressure rapidly intensifying off the Carolinas and pulling away towards the northeast will tighten the gradient. Despite flow generally around 15-25 mph with gusts up to the 30-40 mph range, tidal influences will line up closer to a new moon cycle, and therefore not expecting as impactful of a coastal/river flood event at this time. However, the persistent flow and some remnant tides still trapped in some areas (especially upstream for the St. Johns River) could return flooding concerns, but not until after the short term period. With this forecast package, have begun High Risk for Rip Currents beginning Saturday Morning, in addition to Small Craft Advisories/Gale Warnings over area waters.

Saturday will be overall warmer than Sunday with overall decreasing clouds, and chances for a few isolated showers over southern areas as mentioned above. High temps will be mainly in the 70s, though some areas may see a high temperature overnight tonight due to the cold air advection. Low temps will have a larger discrepancy thanks to the onshore flow: Upper 40s to mid 50s are expected generally north and west of the coast and St. Johns River Valley, with upper 50s to low 60s south and east. Highs will struggle to get out of the 60s for many on Sunday, with just a few clouds inland and more maritime influenced clouds streaming onshore further south and east. Isolated to widely scattered showers may also make it to the immediate coastline at times on Sunday.

LONG TERM /MONDAY THROUGH FRIDAY/

Main Highlights This Period:

- Coastal hazards including tidal flooding, gusty winds, elevated rip risk and surf expected Monday through Wednesday

- Below Normal Temperatures This Period

Strong high pressure will remain oriented to the north and northeast through most or all of the long term period, driving a prolonged period of elevated onshore flow. Model guidance is generally more divided with respect to the behavior of both the upper low and surface low to our northeast towards mid to late week, though there is at least enough agreement with respect to the system lingering near the offshore Carolinas vicinity through at least the Monday/Tuesday time frame, which will keep the enhanced onshore conditions going to an extent. As expected, beach, marine, and river hazards are forecast to continue through much of the long term, with magnitude of coastal/river flooding impacts to be monitored over the coming days - though confidence is growing with respect to at least coastal flood advisory conditions for the St. Johns River and coast. Temperatures will remain generally below normal for long term period.

AVIATION /00Z SATURDAY THROUGH 00Z SUNDAY/

Prevailing VFR conditions are expected this period.

A cold front will move southeast across the area overnight. Winds will pick up following the frontal passage, especially following sunrise Saturday. Elevated and gusty winds will then continue troughout the remainder of this 00z TAF period. A few showers are possible along and just behind the front, but these showers will be isolated.

MARINE

A strong cold front entering the southeastern states will cross our local waters early on Saturday morning. Isolated late afternoon and evening showers and thunderstorms will be possible well ahead of this front, mainly for the waters south of St. Augustine. Scattered showers and isolated thunderstorms will then be possible during the predawn and morning hours on Saturday during the frontal passage. Winds will abruptly shift to northwesterly during the predawn and early morning hours on Saturday, with speeds quickly increasing to Gale levels during the late morning and early afternoon hours as strong high pressure over the southern Plains states in the wake of this front shifts quickly northeastward towards the Ohio Valley by Saturday evening, with this feature then wedging down the southeastern seaboard. Meanwhile, low pressure will develop along the frontal boundary to the east of the Gulf Stream waters off the southeastern U.S. coast on Saturday night, with this feature then drifting westward towards the Outer Banks through the early portions of next week. Gale conditions will likely continue throughout our local waters from Saturday night through Monday night, with seas building to 10-15 feet. Low pressure may become stationary near the southeastern seaboard towards midweek, likely keeping strong north-northeast winds in place.

Rip Currents / High Surf: A lower end moderate risk may develop this afternoon at the northeast FL beaches as onshore winds develop behind the inland moving sea breeze. A high risk will then develop from north to south on Saturday, as strengthening northwesterly winds during the morning shift to northerly during the afternoon hours, with frequent Gale Force wind gusts creating building and dangerous surf conditions. Breakers at the northeast FL beaches will build to the 8-10 foot range on Sunday, with these high surf conditions expected to continue through at least Tuesday. Breakers at the southeast GA beaches will likely build to the 5-7 foot range from Sunday through Tuesday.

FIRE WEATHER

- Patchy High Afternoon Dispersions This Weekend

ELEVATED NIGHTTIME DISPERSION ALONG THE COAST SATURDAY NIGHT AND - Sunday Night

West to southwest winds will be expected today ahead of the front, except generally east of the I-95 corridor this afternoon thanks to a weak sea breeze influence. Dispersions will be mostly in the fair to good range, highest over interior GA where winds aloft will be a bit stronger. A strong but mostly dry cold front moves through tonight and through Saturday, ushering in a dry and windy north to northeasterly flow this weekend and into early next week. This will result in good dispersions this weekend, which could be high at times during the afternoon/evening in some patchy areas. Dispersions will also be elevated near the coastline each night this weekend thanks to persistent breezy onshore flow. This general pattern will continue, albeit become a bit weaker, for much of next week.

FOG POTENTIAL AND OTHER WEATHER REMARKS: Fog formation is not expected through at least the next several days.

HYDROLOGY

Minor flooding will continue along lower portions of the Satilla River during the next several days.

TIDES/COASTAL FLOODING

Minor tidal flooding is possible along the Atlantic coast, Intracoastal Waterway, and throughout the St. Johns River basin beginning on Sunday and likely continuing through at least the middle portion of next week. Significant beach erosion is likely around times of high tide at the northeast FL beaches beginning on Sunday, where breakers will build to the 8-10 foot range, with these high surf conditions expected to continue through at least Tuesday. Minor to moderate beach erosion will be possible around times of high tide at the southeast GA beaches, especially from late Sunday through Tuesday, where breakers will likely build to the 5-7 foot range.

PRELIMINARY POINT TEMPS/POPS

AMG 61 69 49 64 / 10 0 0 0 SSI 68 74 55 69 / 10 20 0 0 JAX 68 74 56 68 / 10 10 0 0 SGJ 71 76 63 71 / 20 20 10 20 GNV 69 75 55 70 / 10 20 0 0 OCF 70 75 57 72 / 30 30 0 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...High Risk for Rip Currents from 6 AM EDT Saturday through late Monday night for FLZ124-125-138-233-333. GA...High Risk for Rip Currents from 6 AM EDT Saturday through late Monday night for GAZ154-166. MARINE...Small Craft Advisory from 6 AM to 2 PM EDT Saturday for AMZ450- 452-454-470-472-474. Gale Warning from 2 PM Saturday to 1 AM EDT Tuesday for AMZ450- 452-454-470-472-474.