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 Through This Week. Dangerous Surf Zone Conditions - High Risk for Rip Currents & Rough, High Surf.

- Breezy Conditions Today, Especially at the Coast.

- Minor Tidal Flooding for St. Johns River Basin & Coast Through At Least Midweek

- Moderate Coastal Flooding Possible This Weekend with upcoming Full Moon Higher Astronomical Tides and Return of Strong and Gusty Northeasterly winds with Significant Beach Erosion Possible at Area Beaches During Times of High Tide

- Potential for Locally Heavy Rain Next Weekend along Portions of the coast

NEAR TERM /THROUGH TONIGHT/

Main Highlights through Tonight:

- Breezy north to northeast winds continue this afternoon with gusts of 25-35 mph, mainly along the NE FL Atlantic Coastal areas

- Coastal & Marine Hazards Continue with high rip current risk, rough surf, beach erosion, and minor tidal flooding during high tide

- Widespread low temps in the 40s over inland SE GA/inland North FL

Breezy North to Northeast flow across the region this afternoon will lessen tonight as pressure gradient relaxes slightly. A few slight shower chances this afternoon along the NE FL Coastal areas of St. Johns/Flagler along with gusty winds to 30-35 mph, otherwise as the pressure gradient slowly relaxes towards sunset expect all areas to have clear skies except for the partly cloudy skies along the NE FL coast to the south of JAX, but all rainfall chances will basically end by sunset or remain as a few sprinkles over the NE FL Coastal waters. Under clear skies and North winds lessening to around 5 mph over inland areas and N-NE 10-15 mph along the Atlantic Coast, expect low temps to drop closer to MOS guidance values, at least 2-4 degrees below NBM guidance by sunrise Tuesday morning. Min temps in the lower/middle 40s are expected across inland SE GA, mid/upper 40s across inland North FL along the I-10 corridor west of JAX and down the Suwannee Valley of I-75. The slightly elevated winds along the Atlantic Coast and St. Johns River Basin will keep low temps in the 50s, and even around 60F at some Atlantic beach front locations where ocean water temps are even warmer. These low temps over inland areas will be the coolest since the early May time frame.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/

Main Highlights This Period:

- Coastal & Marine Hazards To Continue into mid week with high rip current risk, rough surf, beach erosion, and minor tidal flooding.

- Below normal temperatures this period.

Tuesday and Wednesday, mid/upper level riding over the OH and TN valleys will persist as a cutoff upper level low meanders just east of the Mid Atlantic coastline into midweek. Surface high pressure to the north will continue to wedge a drier airmass into the region while a surface low east of the Outer Banks wobbles very slowly northward, while slowly becoming more organized. This will continue elevated NE onshore winds over the area with drier air in the low levels keeping skies sunny on Tuesday while a weak coastal trough developing on Wednesday will bring scattered low level Atlantic stratocumulus clouds back across the coastal waters that will move onshore at times over portions of the NE FL coast from near St Augustine southward where a few sprinkles will occur at times, but not expecting measurable rainfall.

Cold air advection will limit highs on Tuesday to about 5 degrees below normal in the mid 70s along the coast and along and north of the I-10 corridor with upper 70s over north central FL.

Clear skies and very light to calm winds inland winds Tuesday night will brings low into the upper 40s across inland SE GA and the Suwannee Valley and along and north of I-10 west of Jacksonville with low to upper 50s along the SE GA coast into NE FL west of I-95 and low 60s along the NE FL coast where winds will remain elevated off the waters.

Wednesday, sunny skies will boost highs into the upper 70s over SE GA and around 80 along and south of I-10 in NE FL with mid to upper 70s along the coast.

LONG TERM /THURSDAY THROUGH MONDAY/

Main Highlights This Period:

- Increasing northeasterly winds and upcoming Full Moon Cycle will bring potential for Moderate Coastal Flooding impacts within the St Johns river Basin, ICW, and the Atlantic coast, significant beach erosion, high surf, and high risk of rip current Friday into next weekend

- Locally heavy rainfall potential along the NE FL coast next weekend

Thursday, mid to upper level closed trough will open up and merge with a strong trough swinging southeastward from Ontario into the Northeast U.S. which will kick the surface low off the Mid Atlantic coast quickly NE into the north Atlantic waters.

Friday, the strong mid/upper level trough will dive SE away from the Northeast and Mid Atlantic coast with a strong omega ridge briefly building in the wake of the departing strong trough to the NNE from Quebec/Ontario into the Great Lakes. Surface high pressure builds into the eastern Great Lakes and interior New England. Locally, Onshore northeasterly winds will increase significantly by the early afternoon hours turning breezy inland and very breezy and gusty at the coast.

This weekend into Monday, strong ridging will stretch from the Eastern Great Lakes into the OH and TN valleys as the base of the strong trough extending east of the SE U.S. coast will become cutoff from the main flow. This pattern will keep strong surface high pressure near the Mid Atlantic to New England coastline wedging into the lee of the southern appalachians into coastal GA/SC. Global models are showing some signal of a low pressure area developing to our SE in the vicinity of the southern Bahamas. While it is uncertain at this time how close will be to the area, the bottom line is the tightening pressure gradient between the high to the north and the low to the Southeast will bring strong and gusty north to northeasterly winds with Gale force winds over the waters and sustained winds 15-25 mph gusting 35 to 45 mph along our coast and inland to the St Johns river.

This will mean heightened coastal hazards with high surf, moderate to major beach erosion, and potential moderate coastal flooding impacts due to the approach of the upcoming full moon's higher astronomical tides (which peak 0.8 to 1.2 ft MHHW before including any wind effects). Therefore, the enhanced onshore winds will add to higher peak high tides at the coast and the St Johns river where the onshore push north to NE winds will also create a reverse flow effect and increase water levels to at least Moderate flood stage levels (see coastal flooding section for more details).

Inverted troughing over our waters extending from the developing low to the SE will bring in convergent bands of locally heavy showers onshore to the NE FL coast and St Johns river basin with less coverage along the SE GA coast. Rainfall amounts remain uncertain, but some higher end totals of 2-4 inches could fall along the coast of NE FL Saturday into Monday. Should the pattern persists into early next week, rainfall amounts could increase, which also add to coastal flooding impacts along the coast, ICW, and the St Johns river basin. Temperatures will remain near to a little below normal during the period.

AVIATION /18Z MONDAY THROUGH 18Z TUESDAY/

Gusty N-NE winds at 12-15G20-25 knots this afternoon will fade by sunset to 5 knots inland and 8-10 knots along the Atlantic Coastal terminals. A few lingering MVFR CIGS at SGJ through 21Z, otherwise VFR with SKC developing at all TAF sites for the overnight hours. Atmosphere still too dry for any fog formation Tuesday morning and VFR conds will continue to the end of the current TAF period.

MARINE

A tight pressure gradient between high pressure over the eastern states and a strong low pressure well offshore over the western Atlantic will continue to support hazardous marine conditions across the area waters this week. Rough seas up to 9 to 13 feet will persist tonight before easing slowly through mid week as the low offshore moves slowly northward. Small craft advisory level conditions will continue into mid to late week. Another surge of Northeast winds to Gale force is expected to develop late Friday and continue into this weekend.

Rip Currents: Have continued the high risk of rip currents through Wednesday for now given high confidence due to the strong onshore flow. Surf heights of 7 to 10 feet will be coming down gradually as well, but for now have extended the high surf advisory through tonight for SE GA beaches and through Tuesday for NE FL beaches.

FIRE WEATHER

- Elevated Nighttime Dispersions Along The Coast This Week

- Patchy High Daytime Dispersions Near The Coast Into Midweek

High pressure will build into the area from the north through Wednesday as a an area of low pressure develops northeast of the region bring breezy winds inland 12-18 mph with gusts to 25 mph and 15-20 mph with gusts to 30-35 mph along the coast today, decreasing overnight to 5-10 mph overnight inland and 10-15 mph along the coast with gusts to 25 mph. Skies will trend mostly sunny as a drier airmass arrives into the area from the north with only scattered clouds along the NE Florida coast Wednesday. Daytime dispersions will be in the good range through midweek with patchy high dispersions possible near the coast. Night time dispersions will be elevated at coastal locations this evening as elevated onshore winds persist.

Min RH values will remain just above critical levels, falling to the 30-35 percent range over interior SE Georgia and across the Suwannee Valley of NE Florida.

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

HYDROLOGY

The Satilla River at Atkinson is expected to crest later Today, but Minor Flooding will continue along portions of the lower Satilla River Basin through the end of the work week.

TIDES/COASTAL FLOODING

Have extended the Coastal Flood Advisory for Minor Tidal Flooding through Wednesday Night for the entire St. Johns River Basin based on the upcoming tide cycle for this afternoon. Minor Tidal Flooding will continue through the week and into the upcoming weekend for most of the St. Johns Basin and ICWW of the NE FL Atlantic Coast due to the onshore flow peaking mostly in the 1.5 to 1.9 ft above MHHW, but will need to monitor locations in Putnam County just north of Lake George for possible Moderate Tidal Flooding at times which could reach around 2 ft above MHHW.

With another surge of NE winds expected this weekend and approach of the Full Moon on Sunday/Monday October 25/26, the minor tidal flooding will once again expand to cover all of the NE FL/SE GA Atlantic beaches including the St. Johns River Basin, with a higher probability of Moderate Coastal/Tidal flooding during times of high tide, and Coastal Flood Watches/Warnings may be required.

At least some minor to moderate beach erosion continues around times of high tide at area beaches, where breakers up to 6 to 10 feet are expected into Tonight.

PRELIMINARY POINT TEMPS/POPS

AMG 44 75 48 77 / 0 0 0 0 SSI 56 75 58 75 / 0 0 0 0 JAX 51 74 54 78 / 0 0 0 0 SGJ 59 75 62 78 / 0 0 0 0 GNV 51 77 52 81 / 0 0 0 0 OCF 53 78 54 80 / 0 0 0 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...Coastal Flood Advisory until 4 AM EDT Thursday for FLZ038-125- 132-137-138-233-325-333-633. High Risk for Rip Currents through late Wednesday night for FLZ124- 125-138-233-333. High Surf Advisory until 8 PM EDT Tuesday for FLZ124-125-138- 233-333. GA...High Risk for Rip Currents through late Wednesday night for GAZ154- 166. High Surf Advisory until 5 AM EDT Tuesday for GAZ154-166. MARINE...Small Craft Advisory until 8 PM EDT Tuesday for AMZ450. Small Craft Advisory until 4 AM EDT Thursday for AMZ452-454- 470-472-474.