Grantham Lake Georgia Weather Forecast Discussion

665
FXUS62 KJAX 151208
AFDJAX
Area Forecast Discussion
National Weather Service Jacksonville FL
808 AM EDT Wed Oct 15 2025
...New UPDATE...
.KEY MESSAGES...
For the latest NE FL and SE GA Daily Key Messages please visit:
https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf
- High Rip Current Risk through Friday
- Small Craft Advisory Outer Waters
- Tidal Flooding Continues this Week. Highest impacts: St. Johns
  River Basin south of Duval County. Increasing water levels again
  mid-week
- Isolated Thunderstorm Potential Sunday
&&
.UPDATE...
Issued at 805 AM EDT Wed Oct 15 2025
Backdoor front is now over the southern most zones and will exit the
area before noon time. The front will continue to result in a influx
of low level moisture and some occasional scattered to broken stratocu
clouds. Deep northeast flow is noted in the model guidance and will
eventually bring some drier air down into the area tonight. Some
sprinkles possible southern portions midday but dry conditions
continue to prevail. The front will help lower thicknesses and
will result in lower max temps than yesterday with highs in the
upper 70s to around 80 coast and lower 80s inland. Gusty northeast
winds at the coast near 25-30 mph possible, and lower gusts
inland. Overall, little change to the forecast with adjustments to
the sky and temps.
Current marine headlines look good with little change required at
this time.
&&
.NEAR TERM...(Today and Tonight)...
A fast-moving backdoor cool front has pushed south of the forecast
area this morning with breezy northeasterly winds ushered in behind
it. These winds will not be as strong as last week`s Nor`easter
event but gusts up to 25 mph at the immediate beaches will be
possible this afternoon. Increasing winds may slightly increase the
low-end Minor tidal flooding within the St Johns River through
today (more on this in the HYDRO section below). Patchy morning
fog could develop where winds have already decoupled but
widespread dense fog is unlikely.
Outside of the breeziness, a tranquil day is expect for the middle
of meteorological Autumn. Highs will push into the 80s inland while
the cooler onshore flow keeps coastal areas in the upper 70s. Not
much change tonight. Mostly clear skies will allow for excellent
cooling and let lows fall toward the mid/upper 50s for interior
SE GA and the Suwannee River valley while other areas fall to the
low 60s. The coast will be the warm region with lows in the upper
60s to near 70.
&&
.SHORT TERM...(Thursday through Friday night)
Ridging will extend across the region, from a high centered over the
Great Lakes region through Friday. Coastal troughing will be in
place in the northeast flow pattern around the high, leading to
elevated and gusty coastal winds. The high center will gradually
move more toward the northeast into Friday night. The coastal trough
is expected to dissipated Friday night, with onshore flow becoming
more from the east and decreasing.
This will be a dry period with temperatures trending near to a
little below seasonal averages.
&&
.LONG TERM...(Saturday through Tuesday)
The high pressure ridge will move off the east coast Saturday. It
will be another dry day, with the flow gradually coming more from
the southeast through the day. Highs Saturday will be near normal.
A cold front will approach far inland areas Saturday night, then
across region Sunday through Sunday night. A round of showers with a
few embedded thunderstorms are expected to accompany this passage.
At this point stronger storms are not expected, as the best upper
support will be north of the area. Southerly flow ahead of the
boundary, will yield above normal temperatures for Sunday.
High pressure will build across the southeastern US early next week,
with dry weather, and temperatures near seasonal levels.
&&
.AVIATION...
(12Z TAFS)
Issued at 715 AM EDT Wed Oct 15 2025
Some vsby restrictions at VQQ this morning, which should dissipate
soon. Otherwise, a backdoor cool front moving through early today
will bring breezy north to northeast winds later today and also usher
in some stratocumulus to the area with occasional periods of MVFR
cigs, mainly coastal TAFs, and so we have TEMPO groups to cover
this. Stratocumulus and cumulus should diminish and dissipate
after 22z today with mostly clear skies tonight with VFR.
&&
.MARINE...
Northeasterly winds developing across the waters this morning
will persist through the end of the week. Small Craft Exercise
Caution will continue across the waters today and likely on
Thursday. Rising seas has prompted a Small Craft Advisory across
the offshore waters beginning this afternoon. Elevated seas will
persist through at least Friday morning before winds veer
southerly ahead on an incoming cold front. This cold front is
expected to move over the waters Monday with high pressure
building in behind it from the west.
&&
.HYDROLOGY...
Breezy onshore flow will flatten out and at least slightly
reverse the downward trend in high tide levels within the middle
St Johns River (south of Jacksonville) today. Minor flooding will
be possible with both high tides today and possibly through the
end of the week as mild onshore flow persists. Southerly flow
this weekend will lead to lower tidal levels.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG  82  56  82  53 /   0   0   0   0
SSI  77  64  76  63 /   0   0   0   0
JAX  80  61  81  60 /   0   0   0   0
SGJ  79  67  79  67 /  10   0   0   0
GNV  83  59  84  59 /   0   0   0   0
OCF  83  61  84  61 /   0   0   0   0
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Advisory until 6 AM EDT Thursday for FLZ038-132-
     137-138-333-633.
High Rip Current Risk through late Thursday night for FLZ124-125-
     138-233-333.
GA...High Rip Current Risk through late Thursday night for GAZ154-166.
AM...Small Craft Advisory from 1 PM this afternoon to 8 AM EDT Friday
     for AMZ470-472-474.
&&
$$

NWS JAX Office Area Forecast Discussion