Area Forecast Discussion
Issued by NWS Jacksonville, FL
FXUS62 KJAX 270817
Area Forecast Discussion
National Weather Service Jacksonville FL
417 AM EDT SAT AUG 27 2016
.CURRENTLY...sfc high pressure around 1020 mb located over the
Carolinas with tropical wave/disturbance (invest 99L) near 23N76W.
East to northeast low level flow over the region with inverted
sfc trough near the coast. With relatively dry air and light winds
over the inland areas, temps have managed to drop to the cooler
mid to upper 60s...with upper 70s near the coast. An area of
enhance moisture and lift was located about 60 miles east of
Brunswick GA headed westward.
Today through tonight...the main near term issue is the shower
activity that is east of Brunswick GA in association with
inverted trough offshore and at this time expected to arrive
around the 11Z to 16Z time frame. The models have latched onto
this (though with varying intensity and location) and so anticipate
a chance of showers (at this time 30-40 percent) for most of our
GA zones today and portions of NE FL. May need to bump up POPS
further pending later radar trends. Not much in the way of
moderate or even strong instability so for most part will show
just slight chance of tstms. Max temps in the upper 80s at
coast...lower 90s inland. Breezy east to northeast flow along the
coast expected. For tonight...will continue with a 20-30 percent
chance of showers with the activity again becoming focused toward
the coastal zones as the inland areas will stabilize overnight.
Min temps forecast to be 2-3 degrees warmer as low level moisture
increases. Mins in the lower to mid 70s for most part.
Sunday...overall it looks like a bit more moisture is available
for shower and possible tstms activity. POPS are somewhat uniform
across the region at 30-40 percent due to uncertainty on exactly
where convergent bands setup. May be a bit more instability to
work with as well and a low chance of tstms fcst mainly toward
the aftn hours. Highs generally 89-94 expected with partly to
mostly cloudy skies and breezy at times near the coast.
.LONG TERM.../Sunday night through Friday/...
Latest model guidance appears to be in general agreement that
Invest 99L will remain a weak low that tracks across the FL
straits and over the eastern Gulf of Mexico Monday...then tracking
WNW across ctrl Gulf of Mexico Tue/Wed..while suggesting a weak
low will develop off the east coast of ne FL along a stalled
surface trough and track NE away from our area Thu/Fri. This
secondary low complicates the rain forecast during the week.
Following consensus model guidance that suggests high POPs in our
southern counties and over coastal waters Monday...with much lower
values i-10 northward. On Tuesday... guidance has high POPs over
our eastern and southern counties and coastal waters... with lower
values for interior areas of ne FL/se GA. For Wed/Thu...with
precipitation primarily well offshore with surface low...POP
values over land generally range from 20 pct interior se GA to
around 40 pct in our southeastern counties and coastal waters.
This scenario could change based on the actual track of Invest 99L
and whether the weak low develops off the ne FL coast. We return
to a more normal chance POP Friday afternoon for scattered sea-
breeze convection that likely will repeat next weekend.
With onshore flow pattern...consensus guidance has high temps in
upr 80s east to lwr 90s west Mon/Tue...with warming temps Wed-Fri
with mid 90s well inland to near 90 coast.
.AVIATION...VFR through the early morning hours. As an area of
higher moisture moves onshore from near JAX metro area northward
SSI...there is a chance of MVFR cigs and possible brief VSBY
restrictions in brief showers. Time frame around 11Z-16Z...but
VCSH will be carried through the aftn for all terminals given the
difficulty of timing precip with showers this aftn.
.MARINE...East to northeast flow near 15 knots today with seas of
around 3-5 ft expected...just under SCEC headline. Some enhanced
winds speeds possible in the GA zones associated with shower
activity and trough. Periods of higher easterly winds and
seas possible tonight and Monday as pressure gradient increases.
Marine interests are advised to stay informed on the latest
forecasts of Invest 99L which may begin to impact the waters early
Rip Currents: moderate to high risk through the weekend...with
increasing swell activity possible and rough surf. Based on
reports and surf conditions have gone with high risk for NE FL
beaches for today. Beachgoers are urged to use extra precautions
and ask lifeguards about conditions before entering the water.
.PRELIMINARY POINT TEMPS/POPS...
AMG 92 73 92 73 / 30 10 30 10
SSI 88 78 88 77 / 40 20 30 20
JAX 90 74 90 74 / 30 20 30 20
SGJ 88 78 87 77 / 30 40 30 30
GNV 93 74 91 73 / 20 10 40 10
OCF 92 74 92 74 / 30 10 40 10
FL...High Rip Current Risk from 6 AM EDT this morning through this
evening for Coastal Duval-Coastal Nassau-Flagler-St. Johns.