Altamaha Sound, GA to Fernandina Beach, FL 20 - 60 NM Marine Forecast
|Tonight...West Southwest Winds 10 To 15 Knots. Seas 2 To 4 Feet. Dominant Period 8 Seconds. A Chance Of Showers And Thunderstorms.|
|Friday...West Northwest Winds 5 To 10 Knots Becoming South In The Afternoon. Seas 2 To 4 Feet. Dominant Period 9 Seconds. A Chance Of Showers And Thunderstorms.|
|Friday Night...Southwest Winds 5 To 10 Knots. Seas 2 To 3 Feet. Dominant Period 9 Seconds. A Chance Of Showers And A Slight Chance Of Thunderstorms.|
|Saturday...West Southwest Winds 5 To 10 Knots Becoming South Southwest In The Afternoon. Seas 2 To 3 Feet. Dominant Period 9 Seconds. A Chance Of Showers And A Slight Chance Of Thunderstorms.|
|Saturday Night...Southwest Winds 10 To 15 Knots. Seas 2 To 4 Feet Building To 4 To 6 Feet With Occasional Seas Up To 8 Feet After Midnight. Dominant Period 9 Seconds. A Chance Of Showers And A Slight Chance Of Thunderstorms.|
|Sunday...South Southwest Winds 10 To 15 Knots. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet. Dominant Period 8 Seconds. A Chance Of Showers And A Slight Chance Of Thunderstorms.|
|Sunday Night...South Southwest Winds Around 15 Knots. Seas 4 To 6 Feet With Occasional Seas Up To 8 Feet. A Chance Of Showers And Thunderstorms.|
|Monday...South Southwest Winds 10 To 15 Knots. Seas 3 To 5 Feet With Occasional Seas Up To 6 Feet. A Chance Of Showers And Thunderstorms.|
|Monday Night...Southwest Winds 10 To 15 Knots. Seas 3 To 4 Feet. A Chance Of Showers And Thunderstorms.|
|Tuesday...South Southwest Winds 5 To 10 Knots. Seas 2 To 3 Feet. A Chance Of Showers And Thunderstorms.|
AMZ400: Synopsis for Altamaha Sound GA to Flagler Beach FL out to 60 nm|
226 PM EDT Thu Jul 9 2020
Low pressure off the coast of North Carolina will track north- northeastward along the mid-Atlantic coast. The National Hurricane Center is forecasting that this surface low will likely develop into a tropical depression or storm within the next couple of days. A front trailing the departing surface low will linger across the southeast region through Saturday continuing elevated rain chances and prevailing offshore flow over the local waters. A weakening surface front will approach from the west late Sunday into Monday with an increase in southerly winds.
The approximate location of the west wall of the Gulf Stream as of Jul 09, 2020 at 1200 UTC...
- 66 nautical miles east of Flagler Beach.
- 74 nautical miles east of Saint Augustine Beach.
- 82 nautical miles east of Jacksonville Beach. 96 nautical miles east southeast of St Simons Island.
Area Forecast Discussion|
National Weather Service Jacksonville FL
111pm EDT Thu July 9 2020
Near Term - Through Tonight
Similar pattern characterized by WNW steering flow continues across the area with high pressure ridging extending across the southern peninsula from the central Gulf and low pressure to our northeast tracking northward along the mid Atlantic seaboard. Elevated rain chances will continue this late morning through the afternoon. Convective pattern will start this morning with showers and isolated storms edging inland from the GOMEX. With PW between 2.1 and 2.2 inches, we should continue to see plenty of coverage of showers and storms this afternoon. While lapse rates are not conducive for severe storms, with 500 mb temps around -5, there may be a few strong thunderstorms with wind gusts of 35 to 45 mph with some heavy rain. During the early evening hours, the bulk of convection will focus east of highway 301 eastward toward the Atlantic coast where boundary mergers will be maximized through early evening. The lions share off the convection will push offshore by mid to late evening as convection propagating eastward into the adjacent Atlantic waters. After midnight, there will be a chance of an inland shower given the very moist airmass still in place, but the best focus for pre-dawn rain potential will shift back west toward the Gulf Coast region into the Suwannee Valley.
.SHORT TERM [Friday Through Saturday]... Friday, the area will be located near the base of of a mid/upper level trough over the eastern US with mid/upper level ridging centered over the desert southwest and to our east over Bermuda. A departing surface low moving north along the eastern seaboard of the US will leave some weak troughing over the southeast Friday with surface high pressure over the western Gulf of Mexico and the this will allow northwest flow to preside over our area. Moisture levels will be higher on Friday than Saturday as drier air in the low levels arrives from the north in the wake of the departing low with Precipitable water levels between 2.00 to 2.20 inches. Friday will continue to feature scattered to numerous thunderstorms across the area with a threat for strong wind gusts up to 50 mph, locally heavy rainfall from any cells that train over the same areas, and frequent lightning but should keep the potential for severe storms low as the environment remains warm in the mid levels near -5 degrees celsius along with weak shear levels.
Saturday will feature some drier air aloft filtering down from the north that will reduce coverage of showers and storms over SE GA, but may help to increase the threat for strong to severe downburst winds 50 to 60 mph with thunderstorms over NE FL. The drier air aloft will lower precipitable water levels below 1.3 north and west of Waycross, but remain between 1.5 and 1.8 inches from Jacksonville southward. Therefore scattered to numerous thunderstorms to form south of Waycross over Se GA and over NE FL with help from shortwave energy swinging through the region near the base of the trough.
Temperatures will above average as high temperatures rise into the low to mid 90s Friday and the mid 90s Saturday as the drier air aloft allows plentiful daytime heating. Low temperatures on saturday will be slightly above average with lows in the upper 70s along the coast and the mid 70s inland.
.LONG TERM [Sunday Through Thursday]... A pattern of mid/upper level troughing over the eastern US with ridging to our west over the southwest US and to our east near Bermuda will remain Sunday through Tuesday. Scattered Showers and storms chances will continue over NE FL with drier air aloft on Sunday and Tuesday with some higher moisture levels on Monday as a shortwave swings SE into the region within the trough. The drier air aloft will raise the potential for strong to severe downburst wind gusts up to 60 mph over the area.
The pattern will shift on Wednesday into Thursday as mid/upper level ridging moves eastward from the southwest US into the mid MS valley region. This will develop high pressure at the surface over the southeast US and moisture levels will rise as light easterly flow develops off the Atlantic. Scattered showers and storms over NE FL and SE GA are expected as this pattern allows the seabreezes to push inland and converge with high pressure to our north.
Temperatures will be slightly above normal with high temperatures in the mid 90s through Tuesday and then near normal with low 90s Wednesday into Thursday. Low temperatures will remains near to above normal in the upper 70s at the coast and low to mid 70s inland.
Low pressure near the North Carolina coast will track north through Friday as surface high pressure lingers over the central Gulf of Mexico. A front trailing the departing surface low will linger across the southeast region through Saturday continuing elevated rain chances and prevailing offshore flow over the local waters. Prevailing SSW winds 10-15 kts expected with combined seas generally 4 ft or less. A weakening surface front will approach from the west late Sunday into Monday with an increase southerly winds with potential Small Craft Exercise Caution conditions over the outer waters.
Low risk under prevailing offshore flow.
NOAA Jacksonville FL Office: Watches - Warnings - Advisories
FL...None. GA...None. AM...None.