Marine Weather Net

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


REST OF TODAY

S
WINDS
10 - 15
KNOTS

TONIGHT

S
WINDS
10 - 15
KNOTS

MONDAY

SW
WINDS
10 - 15
KNOTS

MONDAY NIGHT

NW
WINDS
10 - 15
KNOTS

The Marine Weather Forecast In Detail:
AMZ470 Forecast Issued: 844 AM EST Sun Feb 28 2021

Rest Of Today...South Winds 10 To 15 Knots. Seas 3 To 5 Feet With A Dominant Period 7 Seconds. Patchy Dense Fog In The Morning.
Tonight...South Winds 10 To 15 Knots. Seas 4 To 5 Feet With A Dominant Period 7 Seconds. Slight Chance Of Showers After Midnight.
Monday...Southwest Winds 10 To 15 Knots. Seas 4 To 5 Feet With A Dominant Period 7 Seconds. Slight Chance Of Showers.
Monday Night...Northwest Winds 10 To 15 Knots Becoming Northeast 15 To 20 Knots After Midnight. Seas 4 To 6 Feet. Slight Chance Of Showers.
Tuesday...Northeast Winds 20 To 25 Knots Diminishing To 15 To 20 Knots In The Afternoon. Seas 6 To 8 Feet. Chance Of Showers.
Tuesday Night...East Winds 15 To 20 Knots Becoming South 15 Knots After Midnight. Seas 5 To 7 Feet. Chance Of Showers And Slight Chance Of Thunderstorms.
Wednesday...West Winds 15 Knots Becoming Northwest In The Afternoon. Seas 5 To 7 Feet. Chance Of Showers And Slight Chance Of Thunderstorms.
Wednesday Night...North Winds 15 Knots. Seas 4 To 5 Feet.
Thursday...North Winds 10 To 15 Knots. Seas 3 To 5 Feet.
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AMZ400: Synopsis for Altamaha Sound GA to Flagler Beach FL out to 60 nm
844 AM EST Sun Feb 28 2021

Dense sea fog is expected over the near shore waters north of Jacksonville Beach this morning. Otherwise, Atlantic high pressure will continue to extend its axis westward across the Florida peninsula today, keeping prevailing southerly winds in place over our waters. A cold front approaches our region from the northwest on Monday and will move through the Georgia waters Monday late afternoon and through the northeast Florida waters Monday evening, accompanied by a few showers. Strong high pressure over the Ohio Valley will wedge down the southeastern seaboard in the wake of the front with strengthening onshore winds towards early Tuesday. This may allow Small Craft Advisory conditions to develop offshore through midweek. Low pressure over the western Gulf of Mexico will move east northeast across the Deep South Wednesday with showers and a few thunderstorms possible ahead of the storm system's cold front before it crosses the area waters in the afternoon. The low will move northeast of the waters and strengthen off the Carolina coast Wednesday night, keeping breezy northwesterly winds in place that will shift to northerly on Thursday as high pressure slowly builds into our area.

Gulf Stream
The approximate location of the west wall of the Gulf Stream as of Feb 27, 2021 at 1200 UTC...
- 64 nautical miles east of Flagler Beach.
- 72 nautical miles east of Saint Augustine Beach.
- 85 nautical miles east southeast of Jacksonville Beach.
- 99 nautical miles east southeast of St Simons Island.
Area Forecast Discussion
National Weather Service Jacksonville FL
1256pm EST Sunday Feb 28 2021

Near Term - Through Tonight
Low stratus ceilings will likely expand over our area through the early morning hours, but dense fog may be confined to the southeast GA coastal locations and adjacent near shore Atlantic waters, where sea fog is expected to develop as dewpoints in the mid 60s continue to run above water temperatures that are mostly around 60 degrees. Breezy southerly winds just off the surface will likely preclude significant fog formation elsewhere despite the unseasonably moist air mass in place, which will likely foster low stratus expansion through the mid-morning hours. Lows should fall to just below daily record warm minimums (see Climate section below), with lower 60s at most locations. These lows are about 15-20 degrees above late February climatology.

Deep-layered ridging will remain in control of our weather pattern through this evening. Meanwhile, troughing will continue to dig southward through the Desert Southwest and will then become cutoff from the main flow pattern tonight. Otherwise, the progressive shortwave trough moving through the Plains states this morning will traverse the Great Lakes states, which will force ridging aloft to flatten and gradually weaken just south of our area tonight.

The axis of Atlantic surface ridging will remain stretched across the Florida peninsula today, keeping a warm south-southwesterly low level wind flow in place locally. Near record warmth is once again expected as stratus erodes into a mid level cloud deck by the late morning hours and then scatters out during the afternoon. Near record warmth will continue, with highs soaring to the mid and upper 80s inland. The Atlantic sea breeze will again develop early in the afternoon and will move slowly inland towards the I-95 corridor by late afternoon. Breezy southeasterly winds will keep highs in the mid to upper 70s at coastal locations north of Jacksonville Beach and lower 80s in coastal St. Johns and Flagler Counties. Sea fog could linger over coastal southeast GA through the mid-afternoon hours before low level flow veers to a more southwesterly component, which should advect low stratus away from the southeast GA beaches before sunset.

Isentropic lift will begin to strengthen over the FL peninsula this evening as Atlantic surface ridging continues to retrograde towards the eastern Bahamas. Isolated to widely scattered showers will likely pivot northward from the Interstate 4 corridor after midnight, with shower activity possibly reaching the I-10 corridor towards sunrise on Monday. Deep-layer flow will become more uniformly southwesterly towards the predawn hours on Monday, and this pattern may advect a low stratus deck and potentially dense fog northeastward from the northeast Gulf of Mexico into the northern Suwannee Valley and possibly portions of inland southeast GA. Warm air advection will keep lows close to daily record warm minimums for March 1st, with mid 60s expected at most locations.

Short Term - Monday Through Tuesday Night
Light southwesterly flow and isentropic ascent Monday morning will bring chances for scattered light rain showers ahead of an approaching cold front. The front will push southeastward toward into SE GA Monday afternoon/evening, then slow down Monday night as it approaches NE FL, bringing showers and possible a few embedded thunderstorms to the region, mainly in SE GA. The front will stall Monday night, weeble wobble during the daytime Tuesday, lifting northward around Tuesday evening/night. Where exactly the front stalls Monday night and when/how far north it lifts Tuesday into Tuesday night is still uncertain. Averaging out the model solutions keeps the highest rainfall totals in SE GA north of a line from Homerville to Cumberland Island.

Temperatures Monday and Monday night looking to be warmer than normal still with the coldest air mass remaining to our north. Tuesday, on the other hand, will depend on where and when the front stalls. Current forecast has temps struggling to peak in the upper 50s to mid 60s in SE GA and in the mid 60s to upper 70s in NE FL on Tuesday. Tuesday night may be warmer than normal again if the front does lift north early in the evening.

Long Term - Wednesday Through Sunday
Another cold front to the west is forecast to push into the region through the day on Wednesday, with model solutions generally exiting the area on Wednesday evening. Dry conditions in the forecast for Thursday and Thursday night with high pressure building over the southeast, but the unsettled pattern returns late in the week as that ridge rolls off the mid-Atlantic coastline and a coastal trough develops ahead of a weak cold front. Highs currently forecast to be in the 60s in SE GA and mostly in the low-mid 70s in NE FL. Lows currently forecast to be generally in the 40s in SE GA, low-mid 50s in NE FL.

Marine
Atlantic ridging will continue to extend its axis westward across the Florida peninsula today, keeping prevailing southerly winds in place over our waters. High pressure will then slide southward as a cold front approaches our region from the northwest on Monday. This front will move through the Georgia waters late on Monday afternoon and through the northeast Florida waters on Monday evening, accompanied by a few showers. Strong high pressure over the Ohio Valley will then wedge down the southeastern seaboard in the wake of the frontal passage, resulting in strengthening onshore winds towards sunrise on Tuesday, with Small Craft Advisory conditions developing offshore through midweek. Meanwhile, low pressure developing over the western Gulf of Mexico will pivot east-northeastward across the Deep South on Wednesday. Showers and a few thunderstorms will be possible ahead of this storm system's cold front, which will cross our area by the early afternoon hours. Low pressure will then continue to strengthen off the Carolina coast on Wednesday night, keeping breezy northwesterly winds in place that will shift to northerly on Thursday as high pressure slowly builds into our area.

Rip Currents
A long period southeasterly ocean swell will combine with a southerly longshore current to create a moderate risk at all area beaches through Monday. Strengthening onshore winds on Tuesday may result in a high rip current risk.

Fire Weather
Thick fog/low clouds this morning will clear out in the late morning, the transport winds from the south will increase to around 15 knots in the afternoon, with mixing heigheights over 4500 ft across inland portions of the area. This will lead to LDSI values over 75 this afternoon, mainly between I-75 and I-95. A cold front will approach the region Monday, then stall out either across our area or to the south on Monday night, lifting back to the north as a warm front Tuesday, with another cold front sweeping in from the west on Wednesday. This will bring rounds of showers and scattered embedded thunderstorms. Thursday should be dry, but chances for showers return Friday.

Hydrology


Moderate River Flooding: Ongoing along the upper Alapaha River. The Alapaha River gage near Statenville will gradually lower to minor flood stage early this week.

Minor River Flooding: Ongoing along most of the St. Marys, Satilla, Altamaha and Santa Fe Rivers. The lower Santa Fe will continue to rise through the end of the week as flow becomes blocked by rising waters near its confluence with the lower Suwannee River, with moderate flooding forecast to begin along the lower Santa Fe River near Three Rivers Estates by this afternoon as minor flooding begins along lower portions of the Suwannee River from the gauge near Luraville southward to around the gauge near Rock Bluff.

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