Altamaha Sound to Fernandina Beach FL Marine Forecast
|Tonight...Southeast Winds 5 To 10 Knots Becoming Northeast After Midnight, Then Increasing To 10 To 15 Knots Late In The Night. Seas 3 To 4 Feet With A Dominant Period 8 Seconds. A Light Chop On The Intracoastal Waters. Slight Chance Of Showers And Thunderstorms In The Evening.|
|Thursday...Northeast Winds 15 To 20 Knots. Seas 3 To 4 Feet With A Dominant Period 8 Seconds. Choppy On The Intracoastal Waters. Slight Chance Of Showers In The Morning. Chance Of Thunderstorms. Chance Of Showers In The Afternoon.|
|Thursday Night...East Winds 10 To 15 Knots Diminishing To 5 To 10 Knots After Midnight. Seas 3 To 5 Feet With A Dominant Period 8 Seconds. A Light Chop On The Intracoastal Waters. Chance Of Showers And Slight Chance Of Thunderstorms.|
|Friday...East Winds 5 To 10 Knots. Seas 3 To 4 Feet. A Light Chop On The Intracoastal Waters. Slight Chance Of Thunderstorms In The Morning. Chance Of Showers. Chance Of Thunderstorms In The Afternoon.|
|Friday Night...East Winds 10 Knots. Seas 3 To 4 Feet. Mostly Smooth On The Intracoastal Waters. Slight Chance Of Showers And Thunderstorms After Midnight.|
|Saturday...East Winds 10 To 15 Knots. Seas 3 To 4 Feet. A Moderate Chop On The Intracoastal Waters. Showers Likely And Slight Chance Of Thunderstorms.|
|Saturday Night...Southeast Winds 10 To 15 Knots. Seas 3 To 4 Feet. Slight Chance Of Showers And Thunderstorms.|
|Sunday...East Winds 10 Knots. Seas 3 To 4 Feet. Chance Of Showers And Thunderstorms.|
|Sunday Night...East Winds 5 To 10 Knots. Seas 3 To 4 Feet.|
|Monday...East Winds 5 To 10 Knots. Seas 2 To 3 Feet. Chance Of Showers And Thunderstorms.|
| AMZ400: Synopsis for Altamaha Sound GA to Flagler Beach FL out to 60 nm|
925 PM EDT Wed Jun 23 2021
The approaching frontal boundary appears to have stalled over the SE GA waters and will linger around the FL/GA border through the end of the week, then dissipate this weekend. Winds will shift to southeasterly tonight then easterly Thursday as high pressure builds to the northeast with elevated winds arriving Thursday as an inverted trough forms over the coastal waters. Easterly winds will continue into next week as high pressure wedges down the east coast. Daily chances of showers and thunderstorms will continue as well. Winds and waves expected to remain below advisory criteria through at least Monday.
The approximate location of the west wall of the Gulf Stream as of Jun 24, 2021 at 1200 UTC...
- 46 nautical miles east northeast of Flagler Beach.
- 44 nautical miles east northeast of Saint Augustine Beach.
- 55 nautical miles east southeast of Jacksonville Beach.
- 97 nautical miles east of St Simons Island.
| Area Forecast Discussion|
National Weather Service Jacksonville FL
932pm EDT Wednesday Jun 23 2021
Showers and thunderstorms are slowly coming to an end with exception of the suwannee valley of inland NE FL and interior SE GA areas where enough sunshine helped to destabilize areas from Waycross north and west north of the frontal boundary and ahead of the Atlantic seabreeze to produce scattered showers and storms. This activity will fade over the next few hours will mainly a heavy rain threat the only impact due to slow storm motion near and north of the stalled frontal boundary. Mostly cloudy skies will last overnight with light southeast winds to near calm inland becoming northeasterly towards dawn. Near normal low temperatures will be in the low to mid 70s at the coast and around 70 degrees inland.
Made a few adjustments to the forecast to lower showers and storms chances over the brunswick area on Thursday and lower our high temperatures based on more cloud cover during the day and the latest guidance into the low to mid 80s. The northeast flow will bring the Atlantic seabreeze well inland during the day and focus likely thunderstorms between the highway 301 and I-75 corridors with more isolated to scattered storm coverage near the Atlantic coast in the early afternoon as the seabreeze initially moves inland.
Near Term - Through Tonight
The approaching front appears to have stalled just north of the FL/GA border, and satellite measurements indicate that southwest flow ahead of the front has brought precipitable water values back up to around 1.9 inches across NE FL. Showers and thunderstorms will continue into this evening, the Gulf coast sea breeze is expected to merge with the much slower Atlantic coast sea breeze just west of the I-95 corridor. Locally heavy rainfall, strong wind gusts, and lightning will be possible with these storms. Shower and storm activity is expected to decrease after sunset and taper off near midnight. High pressure building to the northeast will shift winds tonight to become east northeasterly. Overnight low temperatures will be in the upper 60s to lower 70s, cooler inland than at the coasts.
Short Term - Thursday Through Friday Night
Thursday, the stalled frontal boundary will linger around the FL/GA border, high pressure will continue to build to the northeast, and an inverted coastal trough will develop over the area. This pattern will continue active convection during the daytime hours as diurnal instability develops. Generally easterly flow will allow the Atlantic sea breeze to move well inland, and showers and storms will form along the boundary as it moves inland and merges with the Gulf coast sea breeze near the I-75 corridor.
Friday, the stalled boundary will weaken, and high pressure will continue to build to the northeast. Another active convection day is anticipated due to diurnal instability and decent upper level divergence from upper level troughing developing over the FL peninsula. Easterly flow will continue and shower and storm activity will focus along the Atlantic coast sea breeze again as it moves inland.
High temperatures will be below normal in the 80s due to cloud and precipitation coverage. Low temperatures will be near normal in the upper 60s to middle 70s.
Long Term - Saturday Through Wednesday
Upper level troughing over the area will weaken and the stalled frontal boundary will dissipate this weekend, and the high pressure ridge will remain in place to the northeast through the long term period. Onshore flow is expected to continue, which will allow the Atlantic coast sea breeze to move inland each day. Daily diurnal convection is expected, focusing along the Atlantic coast sea breeze as it moves from east to west across the area and merges with the Gulf coast sea breeze likely near the I-75 corridor. Temperatures will trend near to slightly below normal through the long term period.
NOAA Jacksonville FL Office: Watches - Warnings - Advisories
FL...None. GA...None. AM...None.