Blackshear, Georgia Weather Forecast Discussion

317
FXUS62 KJAX 201901
AFDJAX
Area Forecast Discussion
National Weather Service Jacksonville FL
301 PM EDT Sat Sep 20 2025
...New SYNOPSIS, NEAR TERM, SHORT TERM, LONG TERM, MARINE, FIRE WEATHER, HYDROLOGY, CLIMATE...
.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
- Breezy with a High Rip Current Risk at the Northeast FL Beaches
- Inland Fog Potential Late Tonight and Early Sunday Morning
- Minor Tidal Flooding Possible for the St. Johns River Basin
  Early Next Week
&&
.SYNOPSIS...
Issued at 301 PM EDT Sat Sep 20 2025
Afternoon surface analysis depicts strengthening high pressure
(1031 millibars) building southeastward across the eastern Great
Lakes towards New England. This feature was pushing a "backdoor"
cold front southward across the Delmarva region. Meanwhile,
coastal troughing has sharpened over the Atlantic waters adjacent
to our region, with this feature generating isolated showers
across the Atlantic waters adjacent to coastal St. Johns and
Flagler Counties. Aloft...zonal flow prevails across the Deep
South. Meanwhile, cutoff troughing over the Upper Midwest was
directing a shortwave trough east-southeastward across the
Ozarks. Latest GOES-East derived Total Precipitable Water imagery
indicates that the persistent, unseasonably dry air mass that
prevailed across most of our area during the past week has
gradually moistened, with PWATS generally between 1.25 - 1.5
inches throughout our region, which remains slightly below late
September climatology. Our local pressure gradient is in the
process of gradually tightening, with breezy onshore winds at
coastal locations pushing the Atlantic sea breeze boundary inland
past the Interstate 95 corridor. These onshore winds were keeping
coastal temperatures in the mid to upper 80s, with dewpoints in
the 70s yielding heat index values mostly in the 90-95 degree
range. Isolated showers were developing ahead of the Atlantic sea
breeze boundary across southern portions of the St. Johns River
basin, where additional mesoscale boundaries such as the Lake
George and Crescent Lake breezes were assisting in shower
development. A healthy cumulus field has developed ahead of the
approaching sea breeze boundary for locations west of I-95, where
temperatures at 19Z have soared to around 90 degrees, with
dewpoints falling through the 60s, keeping heat index values
mostly in the low to mid 90s this afternoon.
&&
.NEAR TERM...
(through Tonight)
Issued at 301 PM EDT Sat Sep 20 2025
Our local pressure gradient will continue to gradually tighten
this weekend as strong high pressure builds over New England, with
this feature wedging down the southeastern seaboard and combining
with a sharpening coastal trough offshore to maintain breezy
winds along the I-95 corridor this afternoon. This tightening
gradient will shove the Atlantic sea breeze boundary well inland,
with isolated, low-topped and mostly brief convection possible
for inland locations south of I-10 and along/west of the U.S.
Highway 301 corridor through sunset.
High pressure wedging down the southeastern seaboard will advect a
pocket of drier air southwestward across our area overnight, with
model soundings indicating that PWATs will fall below 1.25 inches.
This drier air should limit any convergent shower activity to the
Atlantic waters, with winds west of U.S.-301 decoupling overnight.
Patchy fog may develop for inland portions of southeast GA during
the predawn hours on Sunday, mainly for locations west of
Waycross. Subsidence and fair skies inland tonight will allow lows
to fall to the mid to upper 60s inland, while an onshore breeze
keeps coastal lows generally in the mid 70s.
&&
.SHORT TERM...
(Sunday through Monday night)
Issued at 301 PM EDT Sat Sep 20 2025
High pressure centered off the New England coast extends down the
eastern seaboard maintaining breezy NNE winds and tightening the
local coastal trough. Another dry day is in store on Sunday with
increased subsidence and a drier airmass (PWATs 1.1-1.4 inches)
over the area. Coastal showers may shift onshore but mainly for
Flagler county. On Monday, moisture gradually advects in from the
south as a frontal boundary lifts northward up the FL peninsula.
Scattered coastal showers move onshore in the morning hours with
isolated thunderstorm coverage by the afternoon, especially from
the St Johns river east to the Atlantic coast. In the NNE flow,
highs will range from low 80s in SE GA coast to low 90s along the
I-75 corridor. Overnight lows will range from the mi/upper 60s
inland to low 70s along the coast.
&&
.LONG TERM...
(Tuesday through Friday)
Issued at 301 PM EDT Sat Sep 20 2025
Upper shortwaves streaming up from the south on Tuesday will
promote scattered coastal showers moving onshore with isolated
afternoon thunderstorms mainly for NE FL. Surface high pressure
quickly builds back in for mid week shifting flow to be more
easterly. Drier conditions on Wednesday limiting any convection to
north-central FL. Cutoff mid/upper low dives southeastward from
the northern Plains into the mid-MS river valley mid to late next
week as its associated surface cold front moves into the SE US
Thursday and approaches the area on Friday. This will bring a
return of scattered convection area-wide. This rain will be
beneficial for our inland areas especially across the Suwannee
River Valley that is currently being highlighted for Moderate
Drought (D1) conditions. Temperatures will be above seasonable
next week with highs in the upper 80s along the coast to the low-
mid 90s inland.
&&
.AVIATION...
(18Z TAFS)
Issued at 155 PM EDT Sat Sep 20 2025
VFR conditions will prevail at the regional terminals through at
least 05Z Sunday. Broken ceilings of 3,500 - 4,500 feet will
progress westward across the inland terminals this afternoon
hours, with clearing from east to west as the Atlantic sea breeze
boundary shifts inland. An isolated, brief shower cannot be ruled
out around GNV between 20Z - 00Z, but confidence was too low to
indicate anything other than vicinity coverage at this time. IFR
to LIFR conditions are expected to develop at VQQ after 05Z.
Northeasterly surface winds will increase to 10-15 this
afternoon at the regional terminals. Surface winds will diminish
towards midnight at the inland terminals, while northeasterly
winds will remain sustained at 5-10 knots overnight at the SSI
and SGJ coastal terminals, where winds will shift slightly to
north-northeasterly towards sunrise. Northeasterly surface winds
will then increase to around 15 knots and gusty at the coastal
terminals before 15Z, while speeds inland increase to 10-15 knots
by 16Z Sunday.
&&
.MARINE...
Issued at 301 PM EDT Sat Sep 20 2025
High pressure building over New England will wedge down the
southeastern seaboard tonight, sharpening a coastal trough
situated offshore. Northeasterly winds will gradually strengthen
to Caution levels of 15-20 knots on Sunday, with scattered
showers and thunderstorms developing, mainly over the offshore
waters and the near shore waters adjacent to northeast Florida.
Seas will build to the 3-5 foot range throughout our local waters
this weekend. High pressure will then gradually weaken as it
shifts southward down the U.S. eastern seaboard early next week,
allowing winds and seas to diminish by midweek.
Rip Currents: Strengthening northeasterly winds will build
breaker heights to the 3-4 foot range later this afternoon at the
northeast FL beaches, creating a high rip current risk. Breakers
of 2-3 feet will likely yield a higher end moderate risk at the
southeast GA beaches. Breakers on Sunday and Monday will build to
the 4-5 foot range at the northeast FL beaches, maintaining a high
risk, while 2-3 foot breakers at the southeast GA beaches likely
will maintain a higher end moderate risk.
&&
.FIRE WEATHER...
Issued at 301 PM EDT Sat Sep 20 2025
The area will remain rain-free this weekend with breezy north-
northeast winds. Elevated mixing heights and transport winds
will lead to very good dispersions this afternoon and high inland
dispersions on Sunday. Dry air over the area will result in Min RH
values dropping into the upper 30s over inland SE GA and portions
of the Suwannee Valley region this weekend. Coastal showers and
afternoon thunderstorm chances will increase early next week.
&&
.HYDROLOGY...
Issued at 301 PM EDT Sat Sep 20 2025
Latest guidance continues to trend downward in terms of coastal
flood potential along the Atlantic coast, while water levels may
rise to around 1.5 feet above Mean Higher High Water (MHHW) early
next week within the St. Johns River basin due to persistent
onshore winds "trapping" tides, especially for locations south of
downtown Jacksonville. This would be near minor flood, or
"nuisance" type flood levels for normally flood prone, low lying
areas along the St. Johns River and its tributaries.
&&
.CLIMATE...
Issued at 301 PM EDT Sat Sep 20 2025
The high temperature reached 90 degrees earlier this afternoon at
the Jacksonville International Airport, making this the 109th day
of high temperatures at or above 90 degrees in 2025. This is now
the third highest number of days with highs at or above 90 degrees
at Jacksonville since records began in 1872, trailing only 1990
(111 days) and 2011 (114 days).
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG  65  89  66  88 /   0   0   0  10
SSI  72  83  73  82 /   0   0  10  30
JAX  68  86  71  85 /   0   0   0  40
SGJ  74  86  73  86 /   0  10  10  40
GNV  67  91  69  89 /   0   0   0  20
OCF  68  90  71  90 /   0   0   0  30
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Monday evening for FLZ124-125-138-
     233-333.
GA...None.
AM...None.
&&
$$

NWS JAX Office Area Forecast Discussion