Marine Weather Net

Altamaha Sound, GA to Fernandina Beach, FL 20 - 60 NM Marine Forecast




10 - 15


10 - 15


15 - 20

The Marine Weather Forecast In Detail:
AMZ470 Forecast Issued: 943 AM EDT Mon Oct 21 2019

Rest Of Today...East Southeast Winds Around 10 Knots. Seas 2 To 3 Feet. Dominant Period 9 Seconds. A Chance Of Showers.
Tonight...Southeast Winds 10 To 15 Knots Becoming South Southwest After Midnight. Seas 3 To 4 Feet. Dominant Period 5 Seconds. A Chance Of Showers And A Slight Chance Of Thunderstorms.
Tuesday...Southwest Winds 10 To 15 Knots. Seas 3 To 4 Feet. Dominant Period 7 Seconds. A Chance Of Showers And A Slight Chance Of Thunderstorms.
Tuesday Night...North Northwest Winds 15 To 20 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 4 Seconds. A Chance Of Showers And A Slight Chance Of Thunderstorms.
Wednesday...North Northeast Winds 15 To 20 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. Dominant Period 5 Seconds.
Wednesday Night And Thursday...East Northeast Winds 10 To 15 Knots. Seas 3 To 4 Feet. A Chance Of.
Thursday Night...East Winds Around 15 Knots. Seas 4 To 5 Feet With Occasional Seas Up To 6 Feet. A Chance Of Showers.
Friday...East Southeast Winds 10 To 15 Knots. Seas 4 To 5 Feet With Occasional Seas Up To 6 Feet. Showers Likely And A Slight Chance Of Thunderstorms.
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AMZ400: Synopsis for Altamaha Sound GA to Flagler Beach FL out to 60 nm
943 AM EDT Mon Oct 21 2019

A warm front will lift up the Florida peninsula today, then a cold front will cross the area Tuesday into Tuesday night. High pressure builds north of the region Wednesday, then northeast Thursday as a warm front lifts northward over Florida. Moderate to strong north winds expected after the frontal passage Tuesday night into Wednesday. Another strong cold front will approach the area late Friday.

Gulf Stream
The approximate location of the west wall of the Gulf Stream as of Oct 19, 2019 at 1200 UTC...
- 47 nautical miles east of Flagler Beach.
- 49 nautical miles east of Saint Augustine Beach.
- 57 nautical miles east of Jacksonville Beach.
- 85 nautical miles east of St Simons Island.
Area Forecast Discussion
National Weather Service Jacksonville FL
924am EDT Monday Oct 21 2019

A weak warm front across south central FL continues to lift northward upward this morning, leading to increased cloud cover over north central FL at about 7.5 to 9.0 kft this morning. This warm frontal feature in concert with diurnal heating, is expected to furnish isolated to scattered afternoon showers, primarily east of I-75 and south of I-10 across northeast Florida when surface dewpoints increase into the lower to mid 70s. Showers are forecast to develop slightly earlier and becoming more numerous across Marion, Flagler, eastern Putnam and southern/central St. Johns this afternoon. In this same area, of Marion, Flagler, eastern Putnam, and southern/central St. Johns is where the best instability will reside this afternoon where CAPES will range between 1500-2500 J/Kg this afternoon which will lend to isolated but embedded thunderstorms.

Near Term - Through Tonight
Areas of fog are expected this morning with a very light wind flow regime and ample low level moisture...and anticipate fog to dissipate by mid morning. As high pressure moves away from the area to the east, a warm front across central FL will push northward in response to large scale trough across the middle part of the U.S. that is digging east-southeast. The warm front will lift into northeast FL by this afternoon and into southeast GA by this evening. Rapid moisture influx with PWATs (Precipitable Waters) of 2 inches and locally high low level convergence along the front will allow for scattered showers/rains and embedded thunderstorms to develop. Best rain chances are forecast for parts of northeast FL mainly to the southeast of a line from Fernandina Beach to Gainesville. Locally heavy downpours and gusty winds are possible mainly around St Johns, Putnam and Flagler counties. Instability not overly impressive but LI is -5 and mid level lapse rates are on the order of 5-6 C/km so a few thunderstorms are to be expected...with an outside chance a strong storm could form given briefly favorable environment of near 35 kt bulk shear and the low level convergence along the warm front. Max temps expected in the 80-85 deg range.

Tonight...the warm front will continue to lift northward and move north of the forecast area after about 06z-09z, while another cold front approaches the area. Scattered showers and some isolated thunderstorms expected with the warm front, and then a lull in the activity before the cold front moves toward the warning zones by early Tuesday morning. Above normal temps min temps expected tonight. Appears some patchy fog will be possible with relatively light winds in place ahead of the cold front.

Short Term - Tuesday Through Wednesday Night
Upper trough over the central U.S. will move east pushing a cold front across the area on Tuesday. A good chance of showers and storms are expected ahead and along the front by afternoon as the airmass destabilizes. Marginal instability along with deep shear of 35-45 knots may result in isolated strong to severe storms. Rain will come to an end Tuesday evening as the cold front pushes south of the area. High pressure will build to the north of the area behind the front on Wednesday advecting in a cooler and drier air mass. Above normal temperatures ahead of the front will fall to near average levels Tuesday night through Wednesday night.

.LONG TERM [Thursday Through Sunday]... Another digging upper trough will move into the Plains by late week which will bring moisture and rain chances back to se Ga/ne Fl. Models continue to differ with the evolution and movement of this system so forecast confidence is low given the model spread. Consensus shows rain chances continuing through the weekend with temperatures at or above average.

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