Marine Weather Net

Fernandina Beach to St. Augustine, FL 20 - 60 NM Marine Forecast


15 - 20


10 - 15




10 - 15

The Marine Weather Forecast In Detail:
AMZ472 Forecast Issued: 732 AM EDT Thu Sep 23 2021

Rest Of Today...North Winds 15 To 20 Knots. Seas 4 To 6 Feet With A Dominant Period 11 Seconds.
Tonight...North Winds 10 To 15 Knots. Seas 4 To 5 Feet With A Dominant Period 10 Seconds.
Friday...Northeast Winds 15 Knots. Seas 4 To 5 Feet With A Dominant Period 9 Seconds.
Friday Night...Northeast Winds 10 To 15 Knots. Seas 4 To 5 Feet.
Saturday...North Winds 5 To 10 Knots. Seas 3 To 4 Feet.
Saturday Night...North Winds 5 To 10 Knots. Seas 3 To 4 Feet.
Sunday...North Winds 5 To 10 Knots. Seas 3 To 4 Feet.
Sunday Night...East Winds 5 To 10 Knots Becoming Northeast After Midnight. Seas 3 To 4 Feet.
Monday...North Winds 5 To 10 Knots Becoming Northeast In The Afternoon. Seas 3 To 4 Feet.
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AMZ400: Synopsis for Altamaha Sound GA to Flagler Beach FL out to 60 nm
732 AM EDT Thu Sep 23 2021

High pressure will build into the area today in wake of a cold frontal passage. Winds will increase from the northwest and north to Caution levels along with building seas today. Winds and seas will decrease Friday into early next week as high pressure settles over the area by early next week.

Gulf Stream
The approximate location of the west wall of the Gulf Stream as of Sep 23, 2021 at 1200 UTC...
- 62 nautical miles east of Flagler Beach.
- 70 nautical miles east of Saint Augustine Beach.
- 82 nautical miles east southeast of Jacksonville Beach.
- 95 nautical miles east northeast of St Simons Island.
Area Forecast Discussion
National Weather Service Jacksonville FL
755am EDT Thu September 23 2021

Surface cold front has cleared all of SE GA and NE FL this morning, while 850mb front aloft is lagging a bit with some moisture producing some clouds in the 4000-8000 ft range across coastal SE GA and most of NE FL that will slowly shift southward or dissipate this afternoon allowing for Mostly Sunny, drier and cooler conditions this afternoon. Max temps likely only in the upper 70s/lower 80s across SE GA and lower/middle 80s across NE FL with no rainfall expected. As high pressure settles just north of the region and the drier airmass pushes further southward into SE GA/NE FL, we expect our first widespread overnight lows in the 50s across SE GA and most of inland NE FL since June 1st, with lower to middle 60s along the Atlantic Coast and St Johns River Basin south of Jacksonville with no fog expected due to the dry airmass.

Average First date in the Fall with lows in the 50s at the local climate sites... Jacksonville, FL (JAX) is October 4th, last was 55F on 06-01-2021 Gainesville, FL (GNV) is October 4th, last was 59F on 05-24-2021 Craig Field, FL (CRG) is October 12th, last was 58F on 05-17-2021 St Simons Is, GA (SSI) is October 9th, last was 58F on 05-16-2021 Alma, GA (AMG) is September 21st, last was 54F on 06-01-2021 ***Alma did reach 58 degrees for a low temp this morning 9-23-2021

20am EDT]... .NEAR TERM [Today through Tonight]...Cold front now pushing se across northeast Florida with dissipating showers will be south of the area by dawn. Northwest to north winds today will advect in much drier air resulting in decreasing cloudiness along with lower humidity levels and cooler temperatures. High temperatures will be in the upper 70/low 80s over se Ga and low to mid 80s across ne Fl. Tonight winds will drop off with clear skies which will allow temperatures to fall into the mid 50s over inland se Ga and in the upper 50s to mid 60s over ne Fl.

.SHORT TERM...[Friday through Saturday]...Surface high pressure ridge will be located from the northern Gulf coast to the Appalachians and then slowly weaken through the period, migrating a bit southwest, while the surface front that passed through the area Wednesday night becomes nearly stationary to the east and south of the area. Much drier and cooler airmass will stay over the area through this period making for pleasant days and nights. Surface flow expected to be north-northeast on Friday. On Saturday, with a weaker pressure gradient and an afternoon thermal trough inland areas will make for more varied winds winds but generally with a north component. With PWATs (Precipitable Waters) well under 1 inch, air-mass too dry to have mention of precip. Temps will be below normal Friday with highs in the lower to mid 80s, and moderating a bit on Saturday with highs in the mid to upper 80s. Lows range from mid 50s over inland southeast GA to mid to upper 60s southeast zones. With light surface winds and clear skies, may see some patchy radiation fog early Saturday and Sunday mornings.

Long Term
[Sunday through Wednesday]...General pattern through the period shows broad mid/upper level troughing off the east coast of the U.S. with weak mid level ridging over the Gulf of Mexico into the lower MS valley. Surface high pressure will be located over the southeast U.S. and should slowly shift a bit southward during the period. A weak trough/front may slide down the southeast U.S. coast Wed-Thu re-enforcing drier air over the area but at this time looks uncertain if this will happen.

Otherwise, long term period will be dry, but some moderation in dewpoints anticipated as daily onshore flow from the Atlantic subtly increases low level moisture. Patchy late night fog may occur inland areas due to light surface winds and mostly clear skies at night.

High temperatures will be near normal this period. Lows will slowly moderate through the period, and trend closer to normal.

NOAA Jacksonville FL Office: Watches - Warnings - Advisories
FL...None. GA...None. AM...None.