textproduct: Jacksonville

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

- Extended Duration of Coastal & Marine Hazards Begins Saturday.

- Coastal Flood Watch - Moderate to Potentially Major Tidal and Coastal Flooding Around Times of High Tide this Weekend thru Early Next Week.

- Gale Watches for the Atlantic Waters from Saturday Afternoon through Monday.

- Wind Advisory Conditions for Coast & St. Johns River Saturday Afternoon through Monday.

- High Rip Current Risk through much of next week.

- Major Beach Erosion near High Tides this Weekend & Next Week.

- Locally Heavy Rainfall Possible for Coastal Northeast FL late Saturday.

NEAR TERM /THROUGH TONIGHT/

Main Highlights: Through Tonight

- High Risk for Rip Currents - Coastal flooding potential

Dry weather conditions will continue through today and tonight with winds strengthening this afternoon as an elevated northeast flow develops between the strengthening high to the north and the developing trough building to the east-southeast of the area. Gusty winds being more noticeable along the coast, with coastal hazards increasing due to strengthening onshore flow. High temperatures for this afternoon will reach up into the mid to upper 70s for inland areas and in the lower to mid 70s along the coast. Overnight low temperatures will drop down into the upper 40s and lower 50s for inland southeast Georgia and in the mid to upper 50s for inland northeast Florida, with min temps in the lower to mid 60s for areas along the coast and near the St Johns River.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/

Main Highlights This Period:

- Coastal and Marine Hazards Increase on Saturday, with Coastal Flood Watches Issued Along the Atlantic Coast, Intracoastal Waterway and St. Johns River Basin. Moderate to Possibly Major Tidal Flooding is Expected Around Times of High Tide.

- Wind Advisory Likely for the Atlantic Coastal Counties this Weekend.

- Gale Watches for the Atlantic Waters from Saturday Afternoon through Monday.

- Dangerous and High Surf Conditions Develop on Saturday , with a High Risk for Deadly Rip Currents and Significant Beach Erosion at Area Beaches this Weekend.

- Locally Heavy Rainfall Possible Along Coastal Northeast FL on Saturday Afternoon and Night.

Strong northeasterly onshore flow continues this weekend as high pressure stretches south along the eastern seaboard and a coastal trough over the offshore waters causing for a tightening pressure gradient between the two features. Showers over the waters will push towards coastal locations by the morning hours on Saturday, and then towards inland locations of NE FL by afternoon hours. Some heavy downpours may be possible as the showers move inland, with some flooding concerns with training showers. The strong onshore flow will bring 25 to 30 mph with gusts of 40 to 45 mph on Saturday afternoon for coast locations and along the St. Johns River Basin, with a Wind Advisory likely to be issued in the upcoming evening forecast package. Sunday, a similar pattern is expected. Strong onshore flow persists with elevated winds and gusts along the same locations as Saturday and showers along the coasts and inland locations towards north central FL.

Mostly clear and sunny conditions away from the coast will allow for afternoon temperatures to warm to the mid to upper 70s this weekend, with a bit cooler temperatures along the coast. Overnight Lows will drop into the lower to upper 50s across SE GA and the Suwannee Valley Region, while the rest of NE FL will be in the lower 60s.

LONG TERM /MONDAY THROUGH THURSDAY/

Main Highlights This Period:

- Coastal and Marine Hazards Continue, with Moderate to Possibly Major Tidal Flooding Possible Around Times of High Tide Early in the Week Along the Atlantic Coast, Intracoastal Waterway, and St. Johns River Basin.

- Wind Advisory Conditions Prevail through Monday Evening at Coastal Locations.

- Gale Watches Continue through at Least Monday for Our Local Atlantic Waters.

- Dangerous and High Surf Conditions Persist, with a High Risk for Deadly Rip Currents and Significant Beach Erosion Possible at Area Beaches through Much of the Upcoming Week.

Strong high pressure over the Mid-Atlantic region early on Monday will slowly settle southward while gradually weakening through midweek. Meanwhile, deep troughing initially in place along the southeastern seaboard will likely cutoff over the Bahamas, with lowering surface pressures to the south of our region keeping a relatively tight local pressure gradient in place on Monday and Tuesday. A slightly drier air mass will continue to overspread our region, but enough low level convergence will remain in place to occasionally bring showers to coastal northeast FL and the St. Johns River basin. Northeasterly winds will remain sustained in the 25-30 mph range for coastal northeast FL on Monday, where winds will frequently gust to 40-45 mph through around sunset before a gradual decrease begins on Monday night. Otherwise, mostly sunny skies will prevail in the drier air mass for inland southeast GA and the Suwannee Valley, while partly to mostly cloudy skies continue elsewhere on Monday. Highs will again remain in the low to mid 70s, except upper 70s for north central FL and the Suwannee Valley.

A gradual loosening of our local pressure gradient on Monday night will allow for winds to decouple overnight across inland southeast GA and northern portions of the Suwannee Valley, where fair skies will allow lows to fall into the mid and upper 40s. Lows elsewhere inland and along the southeast GA coast will fall into the 50s, while breezy onshore winds keep lows in the mid to upper 60s for most of coastal northeast FL.

Cutoff troughing and lower surface pressures will likely meander around the Bahamas on Tuesday before developing zonal flow finally pushes these features northeastward and away from our region towards midweek. However, a reinforcing high pressure center building over New England could begin to wedge down the southeastern seaboard by Wednesday night or Thursday, which would keep gusty northeasterly winds in place at coastal locations for the duration of the upcoming week as coastal troughing remains situated over our local Atlantic waters. This long duration wind event will maintain significant coastal and marine impacts as high astronomical tides persist next week. Scattered coastal showers will also continue to occasionally move onshore, with highs generally remaining in the 70s for the rest of next week. Lows may again fall into the 40s for inland southeast GA and the Suwannee Valley on Tuesday night, with 50s then forecast for the rest of the week for these locations. Lows elsewhere will fall to the 50s, except 65-70 along the northeast FL coast, where gusty onshore winds will prevail.

AVIATION /18Z FRIDAY THROUGH 18Z SATURDAY/

VFR conditions will be in place through the majority of the forecast period with north-northeasterly winds becoming less strong in the evening and overnight hours for inland sites and then becoming more enhanced closer to the end of the forecast period on Saturday, by around 14z-16z. Lower cloud decks and potential for showers are anticipated for late Saturday morning and into the early afternoon.

MARINE

A combination of strong high pressure developing to the north, and a trough of low pressure to the east southeast will result in a tight pressure gradient over area waters this weekend into early next week. This will lead to elevated conditions with gales expected by Saturday afternoon. While the high will weaken to the north into the middle part of next week, an enhanced northeast flow will continue.

Rip Currents / High Surf: Breakers of 5-6 feet at the northeast FL beaches and 3-4 feet at the southeast GA beaches will maintain a high rip current risk today. High Surf Advisories will likely be required by Saturday afternoon at the northeast FL beaches, as breakers build to the 6-7 foot range, while 4-5 foot breakers are expected at the southeast GA beaches. Surf will likely peak on Sunday and Monday, with breakers of 8-10 feet at the northeast FL beaches and 6-7 feet at the southeast GA beaches, and High Surf Advisories will likely be expanded to cover coastal southeast GA during this time frame. High surf conditions may continue through at least midweek at the northeast FL beaches, and a high risk of deadly rip currents will continue during the entire forecast period at all area beaches, where major beach erosion is likely to occur during this extended duration onshore wind event.

FIRE WEATHER

- Critically Low Humidity This Afternoon For Inland Southeast Ga - Marginally High Dispersion Values Inland This Afternoon ELEVATED NIGHTTIME DISPERSION VALUES AT COASTAL LOCATIONS - Tonight Expand To The I-95 Corridor On Saturday And Sunday Nights

Critically low humidity values continue this afternoon across inland southeast Georgia. Showers will begin to move onshore along the northeast Florida coast after midnight tonight, followed by waves of showers throughout the weekend and into Monday along the I-95 corridor in northeast Florida, with activity occasionally extending to coastal southeast Georgia and for inland locations east of U.S. Highway 301 in northeast and north central Florida. Locally heavy downpours will be possible this weekend along the I-95 corridor in northeast Florida. Breezy conditions along coastal locations this evening, creating elevated nighttime dispersion values. Strong northeasterly surface and transport winds will then overspread the I- 95 corridor on Saturday and will continue through Monday, yielding elevated nighttime dispersion values. Breezy conditions are expected inland, creating good daytime dispersion values despite mostly cloudy skies.

FOG POTENTIAL AND OTHER WEATHER REMARKS: Significant fog formation is not expected during the next several days.

HYDROLOGY

Minor flooding will continue along lower portions of the Satilla River during the weekend, with water levels forecast to fall below flood stage by Monday night or Tuesday near the gauge at Atkinson.

TIDES/COASTAL FLOODING

Tidal departures of 0.75 - 1 foot above the predicted astronomical tide continue along the Atlantic coast and within the St. Johns River basin. We expect water levels to top out near the minor flood threshold around times of high tide through tonight, and a Coastal Flood Advisory has been expanded to include all of coastal northeast FL and the entire St. Johns River basin.

Northeast winds surging on Saturday morning will combine with the upcoming full moon on Sunday/Monday Oct 25-26 and lunar perigee on October 28th to increase water levels to at least moderate flooding during times of high tide beginning on Saturday. Confidence is growing for peak water levels of 2.0-3.5 feet above MHHW by the Sunday high tide cycles, and a Coastal Flood Watch has been issued for the Atlantic coast and St. Johns River basin beginning late on Friday night. Tidal stations may approach low-end moderate flooding as early as the Saturday morning high tide, but Sunday and Monday are when the peak tidal flooding will occur.

As the astronomical tides increase this weekend, the combination of the building surf and water levels will lead to higher beach erosion potential. This potential looks higher than the prior northeast wind event around Oct 17th-18th, and the long duration of this event could produce significant erosion during each high tide cycle during the upcoming week.

PRELIMINARY POINT TEMPS/POPS

AMG 74 49 75 54 / 0 0 0 0 SSI 71 59 72 61 / 0 0 20 10 JAX 74 59 73 65 / 0 0 40 40 SGJ 75 64 74 69 / 0 30 90 80 GNV 78 55 77 66 / 0 0 10 40 OCF 78 56 78 66 / 0 0 20 30

JAX WATCHES/WARNINGS/ADVISORIES

FL...Coastal Flood Advisory until 2 AM EDT Saturday for FLZ038-125- 132-137-138-225-233-325-333-633. Coastal Flood Watch from late tonight through Monday evening for FLZ038-124-125-132-137-138-225-233-325-333-633. High Risk for Rip Currents through Monday evening for FLZ124-125- 138-233-333. GA...Coastal Flood Watch from late tonight through Monday evening for GAZ154-166. High Risk for Rip Currents through Monday evening for GAZ154-166. MARINE...Small Craft Advisory until noon EDT Saturday for AMZ450. Gale Watch from Saturday afternoon through Monday evening for AMZ450-452-454-470-472-474. Small Craft Advisory until noon EDT Saturday for AMZ452-454- 470-472-474.