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

- Coastal & Marine Hazards Continue through the Weekend. Small Craft Advisory through Saturday Night. High Risk for Rip Currents, Rough Surf, Elevated Tides and Beach Erosion. Minor Tidal Flooding Continues for the St Johns River

- Hurricane Isaias tracking northward toward northern Gulf coast. Reinvigorated onshore Winds and Additional Periods of Heavy Rain Today and Flood Watch in effect area-wide. Isolated Severe Thunderstorms/Tornadoes Possible this late this evening and on Saturday

UPDATE

Quick update to reflect some of the breezier winds along the coast and to issue a short-fuse wind advisory along the coast from St Johns county northward. Wind gusts recently up to about 40-42 mph at a couple of coastal sites in eastern Duval and about 35 mph in coastal southeast GA. This wind advisory goes through 8 PM.

NEAR TERM / TODAY THROUGH TONIGHT/

Main Highlights:

- Flood Watch in effect for Northeast FL through late This Evening and for Southeast Georgia through Saturday Evening.

- Coastal and Marine Impacts Continue, Including Coastal Flood Advisory for the St. Johns River. High Risk of rip currents and breezy east to southeast winds and rough seas for area coastal waters through tonight and lingers on Saturday.

- Potential for Isolated Severe T'storms Late Today with a Threat for a few brief Tornadoes for inland areas. Tornado watch through 9 PM for Hamilton, Suwannee, and Echols counties.

Increased easterly low level flow combined with the northerly track of Isais in the Gulf is funneling deep tropical moisture across the area. Scattered to numerous showers and a few storms at 230 PM today but will increase in coverage as daytime heating continues to push up into northeast FL as a warm front lifts north over the region. A few severe storms will be possible later on for the inland areas where there is more favorable shear parameters and as rainbands lift up into parts of northern FL. The more favored areas for severe storms, including tornadoes, is placed in for Suwannee, Hamilton, and Echols where there is a tornado watch in effect until 9 PM. There is a possibility that either a new watch is issued later today and/or the current watch is expanded, pending convective evolution. For later tonight, it looks like convection will become more scattered after midnight and mainly confined to inland areas closer to the tropical cyclone.

Meanwhile, stronger gradient easterly winds are reaching 20-25 mph with gusts of about 32-38 mph at 230 PM. These winds will turn more southeasterly tonight and decrease gradually, except breezy at the coast. The potential for moderate rainfall is there given the moist environment and some of the saturated grounds in the region so the Flood Watches remain in effect. Rainfall amounts of about 1-3 inches will be possible, with locally higher amounts possible. Current guidance suggest possible scattered flooding issues later tonight and mainly inland on Saturday.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/

Main Highlights This Period: Saturday through Sunday night

- Potential for strong to severe storms increasing through Saturday, along with flooding chances

Showers and storms continue on Saturday as trailing bands sweep across the local area as Hurricane Isaias continues its inland push from the northern Gulf coast. There will be a potential for strong to severe storms across the area, with the highest potential over southeast Georgia and portions of the Suwannee Valley area as highlighted by the Storm Prediction Center with those locations under a Slight Risk in Day 2 Convective Outlook. Breezy winds with gusts in 30mph range are possible through the afternoon hours with passing bands from Isaias, with stronger gusts likely during any showers or storms that develop. Can't rule out some Tornado development with the passing bands. Additionally there is a Slight to Marginal Risk for Excessive Rainfall across the area on Saturday per the Weather Prediction Center. The Flood Watch remains in effect through Saturday afternoon across SE GA.

By Sunday, the arrival of the cold front will bring drier air into the area. This will result in decreasing chances of showers and storms by the afternoon hours for much of the area, with scattered to numerous showers remaining possible across coastal locations south of the JAX metro.

High temperatures will be in the lower to mid 80s across SE GA and the mid 80s to lower 90s for NE FL, with the warmer temperatures along the southern coastal locations of NE FL. Overnight low temperatures will drop down from out of the lower to mid 70s on Saturday night, then dropping down into the lower to mid 60s on Sunday behind the cold front.

LONG TERM /MONDAY THROUGH FRIDAY/

Main Highlights This Period: Monday through Thursday

- Dry and warm weather next week

Compared to the previous week and this weekend, the upcoming week will be quiet. Drier weather conditions settle in as high pressure builds over the region through midweek. High temperatures for next week will rise to be above the seasonal average with max temps reaching into the mid to upper 80s.

AVIATION /18Z FRIDAY THROUGH 18Z SATURDAY/

Through the 00z time frame, we are looking at some MVFR and IFR conditions, but some prevailing VFR cigs expected for GNV. Expect some occasional IFR conditions starting early for JAX, CRG, and SGJ due to cigs and convection. Going into the 20z-24z time frame, increasing chances of more showers and storms with IFR a good possibility. Later into the evening, conditions will be low-end VFR cigs to MVFR cigs, and still fairly good chances of showers and storms to produce at least MVFR cig/vsby if not IFR. After 06z, more VCSH/VCTS type conditions with areas of MVFR cigs. By mid to late Saturday morning, largely VFR cigs and vsby expected with just VCSH at this time.

Winds will be east to northeast near 12-20G28kt, but lower winds for VQQ and GNV. Winds will decrease somewhat later in the evening while slowly turning southeasterly by the 06z-12z time frame. By mid morning Saturday, winds south-southeast up to 8-14G22kt.

MARINE

A front will lift northward through the waters this afternoon and evening with another high pressure center building in north of the region and to the north northeast on Saturday. Small Craft Advisory conditions expected to continue due to elevated east and southeast winds and seas through Saturday night.

The National Hurricane Center is monitoring Hurricane Isaias in the northeast Gulf. This system is expected to move northward towards the central Gulf coast region today and make landfall tonight. Isais will continue to track north on Saturday over Alabama. Numerous showers and thunderstorms will continue over area waters through tonight and partially on Saturday as tropical moisture surges northward on the eastern periphery of this tropical system. On Sunday afternoon, a weak cold front will move through the forecast waters providing for a wind shift to west and northwest and drier air moving in through early next week.

Rip Currents: Moderate to strong easterly onshore winds today becoming southeasterly on Saturday will support dangerous rip currents and rough surf. High Risk for Rip Currents will likely continue through this weekend with continued breezy/winds, and lingering rough surf at times on Sunday as winds turn southwest.

FIRE WEATHER

- Patchy High Dispersions Sunday

Waves of showers and storms are expected to persist through Saturday afternoon as trailing bands from Hurricane Isaias sweep across the area. Breezy conditions also is expected during the day on Saturday, with occasional gusts near 30 mph. Drier weather begins to develop as a cold front begins to move into the area on Sunday, with shower and storm chances beginning to diminish by the afternoon to evening hours. Quieter weather is expected during the upcoming as high pressure builds over the region into midweek, with winds from the west to northwest.

FOG POTENTIAL AND OTHER WEATHER REMARKS: Dense fog formation is not expected over the next few days. Heavy rainfall may lead to another potential period of flash flooding Tonight and Saturday, with isolated severe thunderstorms will possible. Gusty and erratic winds will occur near thunderstorms.

HYDROLOGY

Portions of the St Marys, Satilla, and tributaries to the St Johns River have risen into minor flood stage. Additional rainfall through the weekend may bring further increases in water levels and lead to other local river rises. Rain-free conditions next week will allow river levels to lower.

TIDES/COASTAL FLOODING

Coastal flooding will persist through the weekend within the St Johns River while decreasing below minor flood stage along the Atlantic coast Today into Saturday, so the Coastal Flood Advisory will remain only along the St Johns river. Anticipate water levels at high tide to be at least at Minor Flood level through the weekend within the St Johns.

PRELIMINARY POINT TEMPS/POPS

AMG 70 82 71 81 / 90 80 60 30 SSI 75 85 74 85 / 80 60 70 30 JAX 73 88 73 85 / 70 70 50 40 SGJ 76 89 74 86 / 60 60 50 60 GNV 73 88 73 85 / 50 80 60 70 OCF 75 88 75 84 / 30 90 50 70

JAX WATCHES/WARNINGS/ADVISORIES

FL...Flood Watch until 2 AM EDT Saturday for FLZ021-023-024-030-031- 035-038-120-124-125-132-136>138-140-220-225-232-233-236- 237-240-322-325-333-340-422-425-433-522-533-633. High Risk for Rip Currents through late Saturday night for FLZ124- 125-138-233-333. Wind Advisory until 8 PM EDT this evening for FLZ124-125-233- 333-433. Coastal Flood Advisory until 4 PM EDT Sunday for FLZ125-132- 137-225-325-633. GA...High Risk for Rip Currents through late Saturday night for GAZ154- 166. Wind Advisory until 8 PM EDT this evening for GAZ154-166. Flood Watch through Saturday evening for GAZ132>136-149- 151>154-162-163-165-166-250-264-350-364. MARINE...Small Craft Advisory until 5 AM EDT Sunday for AMZ450-452-454- 470-472-474.