Area Forecast Discussion
Issued by NWS Jacksonville, FL
FXUS62 KJAX 251815
Area Forecast Discussion
National Weather Service Jacksonville FL
215 PM EDT THU AUG 25 2016
.NEAR TERM (Through Friday night)...
The deep layer ridge across the southeast U.S will gradually shift
north and be across Ohio/West Va by Friday night. The northeast flow
around the high coupled with a coastal trough will bring isolated
showers mainly to coastal northeast Fl tonight into early Friday
morning. Models continue to indicate an onshore flow with strong
subsidence aloft will prevail across much of the area Friday with
only low rain chances across the far south. With stronger subsidence
in the area...max temps expected to be warmer than today with
readings in the lower/mid 90s inland to the upper 80s along the
.SHORT TERM....Sat through Sun night...
Stacked high pressure will continue north of the region with dry air
(PWATs below 1 inch) and subsidence bringing dry conditions over SE
Ga while breezy onshore flow will focus waves of showers and
potentially isolated tstorms moving inland generally along and south
of a JAX to GNV line from the morning through the afternoon. Shower
activity expected to increase over the adjacent Atlantic waters Sat
night into Sun as low pressure 99L approaches south Florida and
drifts slowly WNW through Sun night. An inverted trough axis
extending north of the surface low will advanced toward the local
coastline through early Sun morning with a few showers moving inland
mainly along the NE Florida coast by sunrise.
By Sunday models diverge with the track and intensity of the low as
it nears south Florida and once again used NHC/WPC synoptic pattern
consensus which indicated the low drifting WNW over the eastern
GOMEX during this period. Despite the uncertainty with the low track
and evolution...the local area will continue to experience onshore
flow with increased coastal convergence. Rain chances will increase
from the ESE through Sun afternoon and into Sun night as the parent
surface low drifts westward across the SSE Gulf of Mexico. Expect
mainly showers with clusters of isolated thunderstorms with diurnal
Temperatures will range from the lower 90s well inland toward I-75
to the mid/upper 80s along the coast.Muggy and above normal minimum
temperatures will continue with lows in the mid/upper 70s inland to
near 80 along the coast and inland estuaries.
The extended period of onshore flow and building swells through the
weekend will increase the risk of rip currents. There will also be
an increased potential for elevated water levels along the coast due
to both the onshore flow and also above normal astronomical tides
with the new moon on Sept. 1st.
.LONG TERM...Mon through Thu...
Based on the latest WPC/NHC guidance for 99L...indicated above
normal rain chances spreading northward across the local forecast
area Mon-Thu as the circulation is progged at this time to track
northward across the eastern gulf coast region and then across the
deep south later in the week as it gets pick up by a mid latitude
trough. A low level trough axis will likely linger over the local
forecast area if the low follows this general track...and regardless
of storm structure/intensity. This trough axis combined with high
tropical moisture content (PWAT values potentially 2-2.5 inches)
will bring the potential for a widespread rainfall event across
portions of Florida and potentially SE Ga...especially along the
coast and across the Gulf Coast region. Also based on the latest
track guidance the local forecast area would be positioned on the
ENE side of the low circulation which is not only historically the
wetter side and also the more favored side for tornado formation.
Now is the time for local interests to closely monitor the latest
forecast guidance and ensure their emergency supply kits are
stocked. Review family emergency plans.
.AVIATION...Prevailing VFR. VCSH at SSI and SGJ.
.MARINE...Strong high pressure to the north of the waters will
provide an onshore flow to the waters into the first part of next
week. An exercise caution will probably be needed for the offshore
waters beginning Friday. Marine interests are advised to stay
informed on the latest forecasts of Invest 99L which may begin to
impact the waters early next week.
Rip Currents: Moderate risk at least through Friday due to a
moderate onshore flow.
.PRELIMINARY POINT TEMPS/POPS...
AMG 70 93 70 93 / 10 10 0 10
SSI 78 88 77 88 / 10 10 10 10
JAX 73 91 73 89 / 10 10 10 20
SGJ 78 88 77 87 / 20 20 20 30
GNV 72 91 72 91 / 10 20 10 20
OCF 73 91 73 91 / 10 20 10 30