Marine Weather Net

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


REST OF TONIGHT

SE
WINDS
10 - 15
KNOTS

FRIDAY

SE
WINDS
5 - 10
KNOTS

FRIDAY NIGHT

SE
WINDS
5 - 10
KNOTS

SATURDAY

S
WINDS
5 - 10
KNOTS

The Marine Weather Forecast In Detail:
AMZ472 Forecast Issued: 738 PM EDT Thu Apr 24 2025

Rest Of Tonight...Southeast Winds 10 To 15 Knots. Seas 3 To 4 Feet, Occasionally To 5 Feet. Wave Detail: East 4 Feet At 9 Seconds And Southeast 3 Feet At 5 Seconds.
Friday...Southeast Winds 5 To 10 Knots. Seas 3 To 4 Feet, Occasionally To 5 Feet. Wave Detail: East 4 Feet At 9 Seconds And Southeast 2 Feet At 5 Seconds.
Friday Night...Southeast Winds 5 To 10 Knots. Seas 3 To 4 Feet, Occasionally To 5 Feet. Wave Detail: East 4 Feet At 9 Seconds.
Saturday...South Winds 5 To 10 Knots. Seas 3 To 4 Feet, Occasionally To 5 Feet. Wave Detail: East 4 Feet At 9 Seconds.
Saturday Night...South Winds Around 10 Knots. Seas 3 To 4 Feet, Occasionally To 5 Feet. Wave Detail: Southeast 4 Feet At 9 Seconds. A Slight Chance Of Showers In The Evening.
Sunday...West Winds Around 10 Knots, Becoming Northeast In The Afternoon. Seas 3 To 4 Feet, Occasionally To 5 Feet. Wave Detail: Southeast 4 Feet At 9 Seconds And Northeast 2 Feet At 8 Seconds.
Sunday Night...East Winds 10 To 15 Knots. Seas 3 To 5 Feet, Occasionally To 6 Feet. A Chance Of Showers With A Slight Chance Of Thunderstorms.
Monday...East Winds 10 To 15 Knots. Seas 4 To 5 Feet, Occasionally To 6 Feet. A Chance Of Showers In The Morning. A Slight Chance Of Thunderstorms Through The Day. A Slight Chance Of Showers In The Afternoon. A Slight Chance Of Showers After Midnight.
Tuesday...Southeast Winds Around 10 Knots. Seas 3 To 4 Feet, Occasionally To 5 Feet. Winds And Seas Higher In And Near Thunderstorms.
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Area Forecast Discussion
National Weather Service Jacksonville FL
118am EDT Fri April 25 2025

Synopsis
Issued at 313pm EDT Thu April 24 2025

Afternoon surface analysis depicts strengthening high pressure (1029 millibars) that has moved off the New England coast, but continues to wedge down the southeastern seaboard. A weakening and stationary frontal boundary was located to the south of this feature over the Savannah River Valley. Meanwhile, a cold front was pushing southeastward from the Great Lakes, the Mid- Mississippi Valley and the Southern Plains states. Aloft...ridging located to the northeast of the Bahamas continues to weaken and shift eastward, with a zonal flow pattern remaining in place across the southeastern U.S. A weakening shortwave trough embedded within this zonal flow pattern was shifting eastward across the southern Appalachians, while a stronger shortwave was located upstream from this feature that was approaching the Arklatex region. Our local pressure gradient is tightening this afternoon as high pressure wedges down the southeastern seaboard, with breezy onshore winds keeping coastal temperatures in the upper 70s and lower 80s as of 19Z. Multi-layered cloudiness was holding inland temperatures in the low to mid 80s, where dewpoints were gradually falling through the low and mid 60s.

Near Term
(through Tonight) Issued at 313pm EDT Thu April 24 2025

Shortwave energy traversing the southern Appalachians will keep cool mid-level temperatures in place across our area this afternoon, but deeper moisture values will remain confined to southeast GA and the Suwannee Valley, where PWAT (Precipitable Water) values will rise to the 1.5 - 1.6 inch range by sunset. Convection developing for locations north and west of the Alapaha, Ocmulgee, and Altamaha Rivers is expected to move slowly eastward late this afternoon. Outflow boundaries from this convection may have just enough moisture and instability to allow for isolated to widely scattered showers and thunderstorms to develop early this evening for locations north and west of Waycross. West-northwesterly bulk shear values will only be around 25 knots, and convection that manages to develop over inland southeast GA should remain rather tame, with some slower moving cells potentially producing locally heavy downpours. Any convection that manages to develop this evening will dissipate before midnight, with another round of radiation fog expected to develop at inland locations during the predawn and early morning hours. Locally dense fog will be possible due to a subsident air mass over our area, especially across inland southeast GA. Lows tonight will fall to the lower 60s at most inland locations, ranging to the upper 60s at coastal locations, where a light onshore breeze will continue overnight.

.SHORT TERM... (Friday through Saturday night) Issued at 313pm EDT Thu April 24 2025

High pressure starts to slip further offshore on Friday, which will also shift the surface ridge further south over the Florida Peninsula. While this wont have a significant impact on our weather for Friday, it will slightly weaken the southeasterly onshore flow across the area, and therefore likely bring slightly higher daytime high temperatures as compared to Thursday. Similar to Thursday, a shortwave aloft will pass just north of the region across northern GA Friday and into Friday Night, which could spark a few isolated showers or thunderstorms over far interior GA Friday Evening and into the first part of Friday night as the sea breeze pushes far inland and leftover activity from earlier in the day approaches the Altamaha River Basin. Guidance is in pretty good agreement that slightly more drier air will be mixed in aloft, which therefore will limit convection chances to only around 15% or so in these areas. Highs in the upper 80s to near 90 will be common west of about I-95 inland, with low to mid 80s near the coast. Some mid and high clouds linger Friday Night with lows mostly in the 60s.

A more well defined cold front starts to drop southward across GA during the day on Saturday, crossing southeast GA during Saturday Night and into northeast FL by early Sunday Morning. The front will push high pressure ridging out of the area, however moisture out ahead of the front does not look particularly impressive. If anything, this front will mostly bring with it a wind shift, with little change in both level temps and moisture. That said, the front combined with daytime heating and some moisture aloft will bring with it a low chance for showers and isolated thunderstorms Saturday afternoon and evening, mainly over southeast GA. Veering winds towards the southwest out ahead of the front will also allow temperatures to rise even warmer than both Thursday and Friday, as upper 80s to low 90s will be common across most of the area, except closer to the mid 80s by the immediate coast with a slight sea breeze influence. Low temps remain mild Saturday Night as the front continues to move through, despite winds shifting towards the west to northwest towards Sunday Morning. Lows in the mid to upper 60s will be common.

Long Term
(Sunday through next Thursday) Issued at 313pm EDT Thu April 24 2025

Closer to an anafront type of scenario occurs post cold front for at least the start of the long term period, as higher PWATs (Precipitable Waters) fill into the area for Sunday and linger into Monday, increasing chances for showers and some thunderstorms across the majority of the area. High pressure dives southeastward off the Mid Atlantic coast Monday Night and Tuesday, settling well offshore into the Atlantic by Wednesday. This will gradually increase the amount of subsidence and dry air into the region and therefore chances for convection, especially across eastern portions of the area given the position/orientation of surface ridging. As mentioned in the short term discussion above, there will not be a significant temperature change post frontal passage - especially immediately behind the front. Above average temperatures Sunday fall closer to normal for Monday and Tuesday before moderating towards above normal once again by mid week.

Marine
Issued at 313pm EDT Thu April 24 2025

High pressure centered off the New England coast will continue to extend its axis southwestward across our local waters through Saturday night. Meanwhile, a cold front will move across the southeastern states on Saturday afternoon and evening. This front may bring scattered showers and thunderstorms to our local waters from Sunday through Monday. Strong high pressure building over the Great Lakes states in the wake of this front during the weekend will shift towards the southeastern seaboard early next week, with winds shifting to northeasterly and strengthening across our local waters from Sunday afternoon through Monday as the front pushes south of our local waters. Onshore winds will result in gradually building seas on Sunday night and Monday. This high pressure center will shift offshore on Monday night and Tuesday, allowing southeasterly winds to gradually diminish.

Rip Currents
A persistent easterly ocean swell will combine with breezy onshore winds will keep a lower end moderate risk in place at all area beaches through the upcoming weekend. A high risk is possible early next week as onshore winds strengthen and surf becomes increasingly rough.

Fire Weather
Issued at 1154am EDT Thu April 24 2025

Isolated to widely scattered showers and thunderstorms are possible for locations to the west and north of Waycross late this afternoon through the mid-evening hours. Coverage will become isolated for locations north and west of Waycross on both Friday and Saturday afternoon and evening. Otherwise, a dry air mass will drop minimum relative humidity values to the 30-35 percent range for locations west of the U.S. Highway 301 corridor this afternoon, with values falling to near critical thresholds across portions of north central FL on Friday afternoon. Breezy easterly surface and transport winds will progress inland this afternoon, creating good daytime dispersion values for locations west of the I-95 corridor, while fair values are expected at coastal locations. Transport winds will shift to southeasterly on Friday morning, with southerly transport winds expected across inland portions of southeast GA during the afternoon hours. Lighter speeds will generally result in fair daytime dispersion values, with good values expected across portions of north central FL due to elevated mixing heights. Transport winds will shift to southerly on Saturday for locations south of I-10, while southwesterly transport winds will develop for areas north of I-10. Elevated mixing heigheights and gradually increasing transport speeds will create high daytime dispersion values on Saturday afternoon across inland southeast GA, while good values are forecast for the Suwannee Valley and inland northeast FL. Lighter transport speeds will yield fair daytime dispersion values at coastal locations as well as north central FL on Saturday.

Climate
DAILY RECORD HIGHS

THU FRI SAT SUN

JAX 93 (1999) 92 (1958) 92 (2011) 94 (1986)

GNV 94 (1999) 93 (1896) 93 (1908) 96 (2011)

AMG 93 (1999) 91 (1958) 93 (1986) 96 (1986)

CRG 92 (1999) 91 (2006) 91 (1989) 93 (2011)

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