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

- Flood Watch Today for Atlantic Coast, I-95 Corridor and St Johns and St Mary's River Basins.

- Coastal and Marine Hazards Continue through Friday. Small Craft Advisory Conditions for the Local Waters. High Risk of Rip Currents, High Surf and Substantial Beach Erosion Likely. Coastal Flood Advisory through early Thursday Morning. Minor to Locally Moderate Tidal Flooding Risk through Thursday along the Atlantic Coast, Intracoastal Waterway and Tidal Tributaries of the St. Johns & St. Mary's River Basins. Breezy Northeasterly Winds will Continue at Coastal Locations.

NEAR TERM /THROUGH TONIGHT/

Main Highlights:

- Nor'easter Conditions Develop Today: Coastal Flooding, High Surf, Rip Currents, Gusty Coastal Conditions, and Beach Erosion.

- Localized Flooding Concern for Coastal Northeast FL and Camden County, GA due to saturated conditions and waves of heavy coastal rainbands.

A "backdoor" cold front has slowed and is now stalled across central Florida per the latest analysis early this morning. Soggy conditions will continue today with most areas experiencing light rain or drizzle as isentropic ascent increases across the broadening frontal zone through today. Though isentropic lift doesn't appear particularly strong, it will occur amid "high-grade" moisture with precipitable water still in the 2-2.3" range.

Though most of the rain will be light drizzle and of the stratiform variety today, there will be potential for coastal banding of showers within the gusty northeasterly winds. This may lead to locally high rainfall for beach and coastal communities through the afternoon. Due to the potential banding, mainly along the NE FL coast, and the heavy rain that has fallen over the last few days, a new Flood Watch has been issue for Camden County and NE FL coastal counties and the St Johns River zones. Thunderstorm potential cannot be entirely ruled out, but it will be spotty and most likely across the north- central FL counties closest to the stalled front.

In addition to the soggy conditions, nor'easter conditions gain prominence through today as surface ridging along the Mid Atlantic coast wedges southward and compresses the local gradient. Gusty northeasterly winds, particularly along the coastal interface, may reach top speeds around 35-40 mph. There isn't a strong enough signal for frequent gusts over 40 mph, so have deferred on issuing a Wind Advisory this morning. That said, these winds will lead to dangerous high surf and rip currents at the local beaches beginning this afternoon.

For interests along the Atlantic coast and along the banks of the St. Johns River, the onshore winds will increase the potential for tidal flooding beginning with the late evening (early Wednesday) high tide tonight; more information in the "TIDES/COASTAL FLOODING" section below

Overcast, rainy conditions will tighten the diurnal temperature range with highs only warming about 5-10 degrees above this morning lows. Reading are expected to be in the mid and upper 70s. Some cooler air will make it into SE GA tonight, pushing low temps into the low 60s tonight while low/mid 70s are expected elsewhere.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/

Main Highlights This Period:

- Potential for rounds of heavy rainfall for the Northeast FL coast and North Central FL on Wednesday and Thursday.

- Breezy northeast flow pattern continuing dangerous Surf Zone conditions and coastal flooding.

The area will be between broad surface high pressure to the north and a stalled frontal boundary across central FL with an attendant low pressure off our local Atlantic coast. This setup will maintain breezy northeasterly flow and continue elevated coastal hazards, including minor to locally low end moderate tidal flooding, dangerous surf, strong rip currents, and beach erosion through Thursday. Rounds of showers with embedded thunderstorms move from NE to SW through the day Wednesday and Thursday mainly to coastal areas and NE FL. Coastal convergent bands could develop in the onshore flow providing periods of heavy rainfall and localized flooding. Best chance for rain will be focused in north-central FL due to the proximity to the frontal boundary. Drier air (PWATs ~ 1 in) filtering in from the north will keep inland SE GA generally rain- free. Due to overcast skies and convection, daytime highs will be below seasonable in the upper 70s to low 80s. Overnight lows will range from the low 60s north to low-mid 70s south.

LONG TERM /FRIDAY THROUGH MONDAY/

Main Highlights This Period:

- Elevated northeast flow continues through the end of the week with potential for Minor to Moderate Tidal Flooding, Deadly Surf, and Gusty Coastal Winds.

- Strengthening winds and increasing thunderstorm chances return this weekend.

A low pressure system in the central Gulf will shift northward along the western periphery of Bermuda ridging and track toward the northern Gulf coast Friday into this weekend lifting the stalled front over central FL back northward as a warm front. This will increase rainfall chances northward into SE GA with showers and storms becoming numerous area-wide this weekend. The National Hurricane Center is monitoring the Gulf low giving it a high chance of tropical development by mid-week. No direct tropical impacts are currently expected across northeast Florida and southeast Georgia, although the eventual track, size and intensity of the system will determine the magnitude and distribution of rainfall across the area.

Northeast to east northeast onshore flow will persist through Saturday before shifting southerly Sunday as the front lifts north of the region. Coastal flooding concerns, rough surf, strong rip currents, and beach erosion will remain elevated through the weekend.

Temperatures will remain below seasonable through Saturday, with a gradual warming towards seasonable Sunday into early next week.

AVIATION /12Z TUESDAY THROUGH 12Z WEDNESDAY/

MVFR to IFR conditions will prevail at the regional terminals, with periods of heavier downpours possible through around 04Z Wednesday. North to northeasterly surface winds sustained at 5-10 knots at the inland terminals and around 10 knots at the SSI and SGJ coastal terminals will become uniformly northeasterly while increasing to around 10 knots at the inland terminals and 10-15 knots and gusty at the coastal terminals by 16Z. Speeds will diminish to 5-10 knots at the inland terminals and around 10 knots at the coastal terminals after 00Z.

MARINE

Small Craft Advisory conditions will expand from the coastal Georgia waters southward into the northeast Florida waters this afternoon as a northeasterly wind strengthens along the coast. Occasional gusts to gale force are possible but are expected to prevail around 25 to 30 knots. Seas will rise quickly behind the wind surge with heights around 7 to 10 feet developing late tonight. Prolonged northeasterly winds continue through at least Thursday as an area of low pressure develops offshore the central Florida coast. Winds are expected to turn onshore this weekend and may strengthen to Small Craft Advisory levels once again as high pressure builds in from the north. The National Hurricane Center is monitor the potential development of a tropical disturbance in the Gulf of America later this week and into the weekend..

Rip Currents: A northeasterly wind will surge south along the Georgia and northeast FL coast through today leading to strong rip currents and high, rough surf. High Risk for Rip Currents and a High Surf Advisory will go into effect today and last through at least Thursday morning. There's a high likelihood that onshore winds continue into the weekend resulting in high rip current risk and elevated or possibly high surf.

FIRE WEATHER

- Areas Of Low Daytime Dispersions Inland Northeast FL Today.

- Elevated Nighttime Dispersions Tonight And Wednesday Night at Coastal Locations.

Frontal boundary over northeast Florida will gradually sink into central Florida by midweek. Periods of rain and isolated embedded thunderstorms will move across the area with the bulk of the rain focusing in northeast Florida through mid-week. Extensive cloud cover, showers, and thunderstorms will suppress daytime mixing heights, resulting in poor dispersion across much of the area and continued low dispersions across portions of northeast Florida today. An area of low pressure begins to develop off the local Atlantic coast later today producing breezy northeast winds particularly across coastal northeast Florida and southeast Georgia, through at least Thursday. These elevated winds will likely lead to high overnight dispersions along the coast.

Fog Potential: Gusty and erratic winds will occur near thunderstorms. Heavy rainfall combined with saturated soils will likely produce localized flash flooding through mid-week, with another potential period of heavy rainfall returning this weekend.

HYDROLOGY

A Flood Watch is in effect for coastal northeast FL counties, the St. Johns River zones, and Camden County in southeast Georgia. Additional rainfall amounts of 1 to 3 inches with localized amounts up to 5 inches will heighten the flood risk in the aforementioned areas, especially in urban areas today early evening.

Portions of the St Marys, Satilla, Santa Fe and Alapaha Rivers have begun to rise in response to widespread 4 to 8 inch rainfall over the last several days. Most locations are not expected to rise into flood over the next several days due to the dry conditions and low water levels prior to this recent bout of heavy rain. However, portions of the Satilla and St Marys have reached Minor Flood stage but are generally beginning to peak. With a break in the heavy rain over the next few days, river levels are expected to gradually lower below flood.

TIDES/COASTAL FLOODING

Coastal Flood Advisories remain in effect through Wednesday night. A local nor'easter and high astronomical tides will combine and result in minor to moderate coastal flooding during times of high tide along the Atlantic coast and ICWW, beginning this evening and likely continuing through Thursday during each high tide cycle. Recent heavy rainfall and elevated tides combined with reverse flow will lead to Minor to potentially moderate flooding within the St. Johns River basin beginning Wednesday morning and continuing through this weekend around times of high tide.

PRELIMINARY POINT TEMPS/POPS

AMG 76 64 81 60 / 30 10 0 0 SSI 79 71 80 68 / 90 70 30 10 JAX 76 69 80 69 / 90 60 20 20 SGJ 79 72 80 74 / 90 90 50 40 GNV 76 68 80 70 / 90 80 50 30 OCF 79 70 81 71 / 90 90 80 50

JAX WATCHES/WARNINGS/ADVISORIES

FL...Flood Watch until 8 PM EDT this evening for FLZ024-038-124-125- 132-137-138-225-233-325-333-425-433-533-633. Coastal Flood Advisory until 5 AM EDT Thursday for FLZ124-125- 132-137-138-225-233-325-333-633. High Risk for Rip Currents through late Wednesday night for FLZ124- 125-138-233-333. High Surf Advisory from 5 PM this afternoon to 5 AM EDT Thursday for FLZ124-125-138-233-333. GA...Flood Watch until 8 PM EDT this evening for GAZ165-166. High Surf Advisory from 5 PM this afternoon to 5 AM EDT Thursday for GAZ154-166. Coastal Flood Advisory until 5 AM EDT Thursday for GAZ154-166. High Risk for Rip Currents through late Wednesday night for GAZ154- 166. MARINE...Small Craft Advisory until 5 AM EDT Thursday for AMZ450-452- 470-472. Small Craft Advisory from 5 PM this afternoon to 5 AM EDT Thursday for AMZ454-474.