Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 231311
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
910 AM EDT Wed Aug 23 2017

.UPDATE...Weak sfc high pressure extends over the region with low
pressure to our north and to our south. Tropical wave noted across
the FL straits northeastward to off the coast of east central FL.
Broad mid to upper level trough extends through the eastern U.S. but
mid level flow which becomes more zonal over srn GA and more of col
region over our forecast area...as inverted mid level troughing is
noted from central Cuba to central FL. As noted in prior
discussion...drier is over north central FL per GOES-R imagery with
PWATS down to 1.4-1.6 inches across Marion to Flagler and St Johns
County...with higher values into the I-10 corridor and points nwd
where they are 2 inches.

With the drier air over our southern zones and associated
subsidence...POPs will continue to be a bit low over most of NE FL
around the 20-30 percent range...with higher values indicated for SE
GA more in the 30-40 percent range due to richer moisture and weak
vort advection. Most convection initiated by Atlantic sea breeze and
outflow boundaries. Storm motion will be erratic or drift southeast
to south. A model modified sounding yields SBCAPE of 3500 J/kg and
DCAPE of 735 J/kg. This indicates a potential for gusty downburst
winds, as is typical. Have nudged temps up just a bit with mid 90s
common inland and heat indices reaching the 100-105 range. Isolated
to scattered showers and storms expected inland into the evening
hours before dissipating gradually through midnight.

&&

.AVIATION...VFR conditions expected to prevail. Cu bases will rise
to the low end VFR range (030-050 feet) by late morning and aftn.
Light westerly to northwest winds...except right along the coast as
the seabreeze moves inland and shifts winds southeasterly at 8-10
knots. Isolated to scattered thunderstorms will develop this
afternoon and have VCTS for now.

&&

.MARINE...Current forecast is on track with just minor edits. Buoy
readings show seas 2-3 ft and dominate wave period of 9 seconds.

Rip Currents: east swells are near 2-2.5 ft, and fully dominate the
sea state this morning. Outgoing tide this afternoon with
these seas yields a moderate risk of rip currents.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  95  76  93  74 /  40  40  40  40
SSI  91  78  90  78 /  20  30  40  30
JAX  93  76  93  74 /  20  20  40  20
SGJ  92  75  90  76 /  20  20  30  20
GNV  94  74  92  73 /  20  30  40  20
OCF  95  74  92  74 /  30  30  40  30

&&

.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&

$$

Shashy/Walker



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