Marine Weather Net

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


REST OF TODAY

SW
WINDS
15 - 20
KNOTS

TONIGHT

SW
WINDS
15
KNOTS

MONDAY

NW
WINDS
10 - 15
KNOTS

MONDAY NIGHT

SW
WINDS
5 - 10
KNOTS

The Marine Weather Forecast In Detail:
AMZ474 Forecast Issued: 930 AM EDT Sun Apr 11 2021

SMALL CRAFT SHOULD EXERCISE CAUTION
Rest Of Today...Southwest Winds 15 To 20 Knots. Seas 4 To 6 Feet With A Dominant Period 6 Seconds. Showers And Slight Chance Of Thunderstorms In The Morning, Then Chance Of Showers And Slight Chance Of Thunderstorms In The Afternoon.
Tonight...Southwest Winds 15 Knots Becoming West After Midnight. Seas 3 To 5 Feet With A Dominant Period 11 Seconds. Slight Chance Of Showers.
Monday...Northwest Winds 10 To 15 Knots. Seas 3 To 5 Feet With A Dominant Period 11 Seconds.
Monday Night...Southwest Winds 5 To 10 Knots Becoming West After Midnight. Seas 2 To 3 Feet.
Tuesday...West Winds 5 To 10 Knots Becoming South In The Afternoon. Seas 2 Feet.
Tuesday Night...South Winds 10 Knots Becoming West After Midnight. Seas 2 To 3 Feet.
Wednesday...Northwest Winds 5 To 10 Knots Becoming West In The Afternoon. Seas 2 Feet. Slight Chance Of Showers And Thunderstorms.
Wednesday Night...Southwest Winds 5 To 10 Knots Becoming Northwest 10 To 15 Knots After Midnight. Seas 2 To 3 Feet. Chance Of Showers And Slight Chance Of Thunderstorms.
Thursday...Northeast Winds 10 To 15 Knots. Seas 2 To 3 Feet. Chance Of Showers And Slight Chance Of Thunderstorms.
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AMZ400: Synopsis for Altamaha Sound GA to Flagler Beach FL out to 60 nm
930 AM EDT Sun Apr 11 2021

Showers and thunderstorms will move over the waters through this afternoon ahead of a cold front that will push across the local waters tonight. High pressure over the Gulf Coast region will build east across the Florida peninsula through Tuesday. The high will build farther east offshore of the Florida Atlantic coast midweek as the next frontal system approaches from the north late Tuesday into Wednesday. The front will push south of the local waters Thursday as high pressure builds north of the region.

Gulf Stream
The approximate location of the west wall of the Gulf Stream as of Apr 10, 2021 at 1200 UTC...
- 62 nautical miles east of Flagler Beach.
- 68 nautical miles east of Saint Augustine Beach.
- 79 nautical miles east of Jacksonville Beach.
- 83 nautical miles east of St Simons Island.
Area Forecast Discussion
National Weather Service Jacksonville FL
156pm EDT Sunday April 11 2021

Near Term - Through Tonight
An intense coupled upper level jet combined with a potent shortwave over the northeastern Gulf of Mexico will force a linear MCS to develop across the northeastern Gulf and moving into the Suwannee Valley and northeast Florida before daybreak. The interior fog will dissipate after daybreak. The RAP indicates MLCAPE values reaching 2000-2250 J/kg between 09-12Z over northeast Florida. Expect mostly elevated storms to develop initially. The high-res guidance seems to be far too slow with the convective development (as it is already occurring), so followed closer to a blend of NAM/GFS for placement/timing this morning.

Expect a band of strong showers/storms to form near/over the I-10 corridor by daybreak, with this linear MCS then propagating southward across northeast Florida through the morning and into the mid afternoon. Steep mid level lapse rates in the 7-8 C/km and cold temperatures aloft are expected across northeast Florida. Marginally severe hail, rainfall rates of 2+ inches per hour, and gusty winds in the 40-60 mph range are expected to mix down in the stronger convection around daybreak to 15Z as storms remain mostly elevated. Afterwards, increasing instability and 50 knot mid level flow is forecast to push into north central and central Florida, and this is forecast to lead to a strengthening MCS as it moves towards the southern portion of the area (Marion, Putnam, and Flagler Counties). The main threat will be damaging winds along/south of a line from roughly Gainesville to St. Augustine in the late morning to mid afternoon, and especially southward. An isolated tornado and large hail cannot be ruled out as well in this area. Very heavy rainfall rates are expected with these storms, with 1-2 inches of rainfall and locally higher amounts expected across portions of northeast Florida. Ponding on roadways and localized flooding is possible.

The MCS will move south of the area by the mid/late afternoon, and a few showers/sprinkles will remain possible across the area ahead of the cold front. The cold front is forecast to push into the area around 00Z, clearing the area before daybreak on Monday. Any light showers/sprinkles will end overnight.

Highs today will be in the 70s. Overnight lows will be in the mid 50s across interior southeast Georgia, and the upper 50s to lower 60s elsewhere.

.SHORT TERM [Monday Through Tuesday]... Broad upper level ridging and surface high pressure will be in place across the region Monday into Tuesday which will promote warm and dry conditions. Ridging begins to weaken on Tuesday as a cold front enters the region. Temperatures will be above normal with highs in the 80s and lows in the 50s and 60s.

Long Term - Wednesday Through Sunday
A cold front stretching from a low over the Great Lakes will push southeast through the area Wednesday into Thursday and stall over central Florida into the weekend. This will lead to unsettled weather and rain chances Wednesday through the end of the week. Temperatures will be above normal on Wednesday then return to around normal through the weekend.

Marine
A cold front will move across the local waters tonight. High pressure over the Gulf Coast region will build east across the Florida peninsula through Tuesday. The high will build farther east offshore of the Florida Atlantic coast midweek as the next frontal system approaches from the north late Tuesday into Wednesday. The front will push south of the local waters Thursday as high pressure builds north of the region.

Rip Currents
Moderate risk of rip currents at the northeast Florida beaches through Monday. Low risk of rip currents today and Moderate risk of rip currents on Monday at the southeast Georgia beaches.

Hydrology
There is a Marginal Risk of Excessive Rainfall today across portions of northeast Florida. Rainfall amounts of 1-2 inches with locally higher amounts are possible, especially along/south of a line from roughly Gainesville to St. Augustine. Ponding on roadways and localized flooding is possible.

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