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

- Marine & Coastal Hazards Continue this Week. Dangerous Surf Zone High Risk for Rip Currents. Minor Tidal Flooding Continues Within Portions of the St. Johns River Basin and

- Atlantic coast south of St Augustine

- Strong Northeasterly Winds Develop Friday Night Along the I-95 Corridor. Moderate Tidal and Coastal Flooding Likely During the Upcoming Weekend. Gale Conditions Possible for the Local Atlantic Waters. Dangerous/High Surf Conditions with a High Risk for Rip Currents at Area Beaches

- Locally Heavy Rainfall Possible this Weekend for Coastal Northeast FL

NEAR TERM /THROUGH TONIGHT/

Main Highlights:

- High Risk for Rip Currents - Minor coastal flooding portions of NE FL

Broad high pressure system anchored to the north and subsident conditions will continue to allow for clear skies and little sensible weather other than pleasant afternoons and cool mornings. Excellent radiational cooling early this morning will allow the lows to fall into the mid to upper 40s for the Suwannee Valley / inland southeast GA, and the lower to mid 50s for north central FL, while persistent onshore flow keeps temps in the upper 50s to around 60 closer to the coast.

Northeast to east flow expected again today with breezy conditions toward the coast. Highs will be in the upper 70s to around 80 inland and mid 70s toward the coast. Similar overnight lows for Thursday night/early Friday...generally in the upper 40s to around 50 from Suwannee Valley northward, and lower to mid 50s north central FL, and given some onshore flow at the coast around 60 degrees there.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/

Main Highlights This Period: Thursday through Friday night

- A high risk for rip currents continues

Strong high pressure will build to the north this period. An inverted trough is expected to develop east of the area Friday night. The pressure gradient over the area will increase steadily through the period due to strengthening high, then the addition of the inverted trough later in the period. As the gradient tightens winds will pick up. With the position of the high, the winds will be onshore, and the increase in speed will be most noticeable near the coast.

It will be dry through Friday, then convergence associated with the inverted trough will bring a chance for showers to mainly coastal areas.

Temperatures will be below average through Friday. With the increase in flow across the coastal waters Friday night, temperatures will be closer to average, and above closer to the coast.

LONG TERM /SUNDAY THROUGH WEDNESDAY/

Main Highlights This Period: Saturday through Wenesdday

- Coastal hazards expected due to strong onshore flow Saturday through Monday - Potential for localized flooding in heavy rain bands this weekend mainly east of I95

Strong high pressure will remain centered to the north, with inverted troughing to the east over the weekend. The high will slowly weaken, as it sinks south closer to the region early next week. This pattern will result in a gusty onshore flow. Coastal hazards are expected over the weekend into early next week, such as rip currents, high surf, beach erosion and minor coastal flooding. Due to convergence from inverted trough mainly coastal showers are expected Saturday through Monday. A few coastal thunderstorms will be possible Saturday. Localized flooding due to heavy rainfall will be possible over the weekend, mainly east of I95.

The high will continue to weaken as it becomes centered more toward the northeast during the middle part of next week. While the flow will continue to be onshore, it will be weaker, so winds will trend lighter. The chance for coastal showers will also decrease toward mid week.

High temperatures will be below average throughout this period. Lows

AVIATION /12Z THURSDAY THROUGH 12Z FRIDAY/

VFR conditions to prevail this TAF period with only a few cumulus over northeast FL this afternoon. Light northerly or variable sfc winds early this morning except for about NNE 10 kt at SGJ North- northeast winds should pick up 8-12 kt after 14z for all TAFs. Winds will be more mild and variable during the overnight hours starting by around 00z.

MARINE

Through the weekend, high pressure ridge located to the north of the area will build while a trough of low pressure develops just south of the Bahamas. This will continue to support hazardous marine conditions across most of the area waters through tonight. As the pressure gradient tightens further on Friday, strengthening northeast winds and building seas are expected and will continue into the weekend and early next week. Northeast winds to Gale force may develop as early as Friday night and become likely for the weekend into early next week. A surge of moisture this weekend will also support elevated chances for moderate to heavy showers which lasts from Saturday through Monday.

Rip Currents: High risk of rip currents continues much of this week and weekend given the elevated surf conditions and onshore flow. Elevated surf will continue to be a problem the next few days for any swimmer entering the surf zone. Looking ahead, high surf advisory looks probable for the weekend as northeast flow increases with surf estimated to reach upwards of 7 to 10 feet by Sunday.

FIRE WEATHER

- Inland Rh Values Fall To Around 30 Inland Today - Inland Se Ga Rh Values Fall To Around 30 Inland Se Ga Friday - Patchy High Dispersions Friday Through Sunday

High pressure to the north will gradually strengthen over the next few days. An inverted trough will develop east of the area over the weekend. Elevated onshore flow is expected through much of this next week. Mainly coastal showers are forecsat over the weekend, which may be heavy, and produce localized flooding.

FOG POTENTIAL AND OTHER WEATHER REMARKS: Significant fog formation is not expected the next few days. A few coastal thunderstorms are possible Saturday.

HYDROLOGY

The Satilla River at Atkinson is slowly coming down and is now just below 14 ft, and is forecast to reach 13 feet by Monday night into early Tuesday morning.

TIDES/COASTAL FLOODING

Recent observations show minor flooding still occurring from Downtown Jacksonville upstream/southward to Satsuma. Peak water levels have been from 1.6 to 1.9 ft MHHW in the past 24 hours, while from Southbank/Main Street to Dames Point and Mayport peaked just below 1.6 ft so just below minor at this time. The combination of departures of 1 to 1.5 ft and latest PETSS guidance show water levels pushing a little higher today through Friday and still in minor category. Therefore, the advisory is being continued for the current area.

Looking ahead to the weekend, another surge of northeast winds and the full moon on Sunday/Monday Oct 25-26 will push water levels up further, especially for the coast. Confidence is growing for moderate tidal flooding (up to 2.5 ft MHHW) and coastal flood watches/warnings may be needed. Some tidal stations may reach low- end moderate flooding as early as the Saturday morning high tide, but Sunday and Monday are when the best chances of moderate tidal flooding would occur.

At the beaches, minor beach erosion will continue the next couple of days especially at times of high tide due to the rough surf. As the astronomical tides increase later this week and over the weekend, the combination of the increased 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.

PRELIMINARY POINT TEMPS/POPS

AMG 79 48 73 51 / 0 0 0 0 SSI 75 57 70 60 / 0 0 0 10 JAX 77 53 73 58 / 0 0 0 10 SGJ 76 60 75 67 / 0 0 0 40 GNV 80 51 77 57 / 0 0 0 0 OCF 80 53 78 58 / 0 0 0 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...Coastal Flood Advisory until 2 AM EDT Saturday for FLZ038-125- 132-137-138-225-325-333-633. High Risk for Rip Currents through late Friday night for FLZ124-125- 138-233-333. GA...High Risk for Rip Currents through late Friday night for GAZ154-166. MARINE...Small Craft Advisory until 2 AM EDT Saturday for AMZ470-472- 474.