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

- Tornado & Flash Flood Risk Continues Today & This Evening. Greatest Concern Areas: Southeast GA & Suwannee River Valley

- Coastal & Marine Hazards through the Weekend. Small Craft Advisory through Tonight. High Risk for Rip Currents, Rough Surf, Elevated Tides & Beach Erosion, Minor to Moderate Tidal Flooding St. Johns Basin Continues

NEAR TERM /THROUGH TONIGHT/

Main Highlights Today and Tonight:

- Flood Watch in effect for The Suwannee Valley and Southeast Georgia through Early This Evening.

- Isolated Severe T'storms this afternoon/evening with a Threat for a few brief Tornadoes for the Suwannee Valley and inland Southeast Georgia.

- Coastal & Marine Hazards through the Weekend. Small Craft Advisory through Tonight. High Risk for Rip Currents, Rough Surf, Elevated Tides & Beach Erosion, Minor to Moderate Tidal Flooding St. Johns Basin Continues

A warm front stretches from the remnant circulation from Isaias over central AL across central GA and into the SC coast leaving our area in the warm sector. Bands of showers and storms trailing post- tropical Isaias to the NW will move across our area from the WSW this afternoon into this evening. The combination of deep tropical moisture (PWATs 2.1-2.3 in) and strong heating in the wake of the warm front allowed for ample destabilization (MLCAPE 1500-2500 J/kg) of the airmass overhead. Decent vertical wind shear (35 kts SFC-3km) and veering, nearly unidirectional wind profiles will support strong to severe thunderstorms capable of producing wind gusts of 40-60 mph area-wide and a few brief tornadoes mainly for inland SE GA and Suwannee Valley this afternoon into evening. Along with the severe threat, a Flood Watch remains in effect through early this evening for all of SE GA and the Suwannee Valley where bands of heavier showers and thunderstorms could bring another 1-3 inches of rain with locally higher amounts. Due to saturated soils, Duval county may need a Flood Watch especially if heavier downpours coincide with the St Johns River high tide cycle.

Another lull in rain and T'storm activity is expected tonight after sunset as Isaias' associated cold front shifts eastward across the FL panhandle and into SE GA and NE FL towards sunrise. The cold front will bring another line of showers and embedded storms across the area in the pre-dawn hours. Drier air begins to filter into the region from the NW scouring out the tropical airmass. Lows will fall into the upper 60s over far inland SE GA, but remain the low to mid 70s across NE FL and eastern areas of SE GA under thinning high level clouds and winds turning southwesterly just ahead of the front.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/

Main Highlights This Period:

- Convection will clear out by end of Sunday

- Dry weather conditions following the frontal passage, on Monday

A cold front will continue to sweep across the area on Sunday, bringing scattered showers and isolated storms along the boundary as it moves offshore. Drier air builds in behind the frontal boundary, chances of showers and storms will decrease through the rest of the day. By Monday, northwesterly winds will continue as a dry airmass settles over the area bringing mostly clear skies and dry weather to start the upcoming week.

High temperatures will reach into the lower to mid 80s across much of the area, with locations behind the front in the upper 70s. By Monday, temperatures will be a bit warmer with daytime highs in the mid 80s. Overnight low temperatures will dip into the lower to mid 60s on behind the cold front Sunday night. These lower temperatures will continue Monday night as skies remain clear.

LONG TERM /TUESDAY THROUGH SATURDAY/

Main Highlights This Period:

- Dry and warm weather next week

- Diurnal sea breeze winds by Friday

Predominantly benign weather will be in place through next week as the dry air mass remains in place over the forecast area bringing clear skies and warm weather through midweek. Partly cloudy skies with chances for diurnal showers will increase going into the end of the week as the remnants of Isaias pushes towards the Atlantic up to the north and shifts the prevailing flow about to become a more onshore southeasterly direction, increasing the reach of diurnal sea breeze winds reaching inland past the St Johns River. Daily high temperatures will initially be above the seasonal average through midweek, reaching into the upper 80s, and then dropping to be nearer to the seasonal average by the end of the week.

AVIATION /18Z SATURDAY THROUGH 18Z SUNDAY/

Southerly winds around 10 kts will become breezy in the next couple of hours with gusts around 20 kts. MVFR CIGS over the NE FL terminals will gradually lift as rounds of showers and storms move from south to north from 18-24Z. A strong to severe storm may be possible in the 20-24Z time frame. Have TEMPO/PROB30s for gusty MVFR TSRA activity with 30 knot potential at all terminals. Coverage decreases after 00Z. Another round of showers will move across the terminals between 06-12Z. Winds shift to WSW by 12Z.

MARINE

A warm front north of the waters will continue to lift northward as the remnants of Post-Tropical Cyclone Isaias move northwest of the area. This will continue Small Craft Advisory conditions of elevated southerly winds and seas for the offshore waters through tonight. A round of showers and thunderstorms will move through the waters today as tropical moisture moves over the region. Winds will become westerly on Sunday and gradually decrease as a cold front moves through and exits east of the waters. The cold front will bring showers and thunderstorms early in the day on Sunday with high pressure then building in from the west. High pressure will build over the waters and lower rain chances for Monday into much of next week.

Rip Currents: Elevated southeasterly winds Today will support dangerous rip currents and rough surf. Rip current risk becomes moderate on Sunday as flow shifts to west-southwesterly.

FIRE WEATHER

ISOLATED TO SCATTERED SEVERE STORMS POSSIBLE THIS AFTERNOON INTO EVENING - High Low Dispersions Tonight - Patchy High Dispersions Inland Se Ga Sunday

Waves of showers and storms are expected to persist through this afternoon as trailing bands from Post-tropical Isaias sweep across the area. Breezy conditions also are expected today, with occasional gusts to 25-30 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. Breezy westerly transport winds and elevated mixing heights will lead to high dispersions on Sunday for southeast Georgia. Quieter weather is expected for next week 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 for the next few days. Heavy rainfall may lead to another potential period of flash flooding today, with a potential for isolated to scattered severe thunderstorms. Gusty and erratic winds will develop near thunderstorms. A couple of tornadoes are possible this afternoon.

HYDROLOGY

A Flood Watch remains in effect through early this evening for all of SE GA and the Suwannee Valley where bands of heavier showers and thunderstorms could bring another 1-3 inches of rain with locally higher amounts. Due to saturated soils, Duval county may need a Flood Watch especially if heavier downpours coincide with the St Johns River high tide cycle.

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

River levels along the St Johns River and its tributaries crested at low-end moderate flood stage with this morning's high tide cycle. Coastal Flood Advisory was upgraded to a Warning through tonight for the next couple of high tide cycles. Minor flooding is anticipated for Sunday and a gradual decrease is anticipated for early next week as the flow shifts to west- southwesterly and the river is allowed to drain back into the Atlantic.

PRELIMINARY POINT TEMPS/POPS

AMG 69 80 64 84 / 70 10 0 0 SSI 74 84 64 85 / 50 40 0 0 JAX 73 85 64 86 / 50 40 0 0 SGJ 74 85 67 86 / 60 40 0 0 GNV 73 83 64 85 / 80 50 0 0 OCF 75 82 65 83 / 80 70 0 0

JAX WATCHES/WARNINGS/ADVISORIES

FL...Flood Watch until 8 PM EDT this evening for FLZ021-023-030-035- 120-220-322-422-522. Coastal Flood Advisory until 5 PM EDT Sunday for FLZ038. High Risk for Rip Currents through late tonight for FLZ124-125-138- 233-333. Coastal Flood Warning until 6 AM EDT Sunday for FLZ125-132-137- 225-325-633. Coastal Flood Advisory from 6 AM to 5 PM EDT Sunday for FLZ125- 132-137-225-325-633. GA...Flood Watch until 8 PM EDT this evening for GAZ132>136-149- 151>154-162-163-165-166-250-264-350-364. High Risk for Rip Currents through late tonight for GAZ154-166. MARINE...Small Craft Advisory until 8 AM EDT Sunday for AMZ470-472-474.