Area Forecast Discussion
Issued by NWS Jacksonville, FL

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FXUS62 KJAX 240747
AFDJAX

Area Forecast Discussion
National Weather Service Jacksonville FL
347 AM EDT Thu Aug 24 2017

.NEAR TERM (Through Tonight)...
A tail end of a short wave trough and associated cold front
will approach and move across southeast Ga by tonight. A
tropical wave across the eastern Gulf Of Mexico will move
ashore the west coast of Fl tonight. Light steering winds...
deep tropical moisture...seabreezes and outflows...plus added
lift and convergence from the approaching front will lead to
scattered mainly diurnal driven storms today. Model forecast
soundings suggest there will be a weak cap between 850-700 MB
which may initially inhibit convection...but there will be enough
forcing especially by the afternoon to easily overcome the cap
especially as the front approaches the area in addition to
seabreezes and outflows across the area. Appears best coverage of
storms will be across most of southeast Ga and inland areas of
Ne Fl generally between U.S. 301 and I-75 where the most boundary
collisions will occur. While severe storms appear unlikely...
it will still be unstable enough along with steep low level
lapse rates (from heating) for a few strong storms that could
produce strong and gusty winds in addition to frequent lightning
and locally heavy rain in excess of 2 inches. The storms will
linger into the early part of the evening before fading out.
Afternoon temps in the lower/mid 90s combined with the humidity
will produce heat indices from around 105 degrees across inland
areas while coastal areas will reach around 90 degrees with
heat indices of around 100 to 102 degrees.

&&

.SHORT TERM (Friday and Saturday)...
Base of a large upper level trough should be in place across the
Southeast to start the short term. A weak stationary front will
just to our north should be just about dissipated, and keep weak
troughing along the Florida/Georgia border. Scattered
thunderstorms are possible across the area on Friday, but will
likely start focusing closer to the coast and mainly just across
north Florida by Saturday. A tropical wave will start moving
northward from south Florida across the coastal waters, and the
pressure gradient will start to tighten as the wave strengthens
into a low pressure system Saturday. PWAT values will vary between
1.75 and 2.1 inches across Florida as the surface low develops,
with some drier air filtering into southeast Georgia. At this
time, rain chances are high but with PWATS near average or just
above, widespread heavy rainfall doesn`t appear likely. With
abundant cloud cover, high temperatures Saturday will only reach
the mid to upper 80s across southeast Georgia and northeast
Florida.

.LONG TERM (Sunday through Thursday)...
While the models are in fair agreement through about Sunday,
things start deviating by Monday regarding the low pressure
system`s strength and track up the coast. For now have trended
with the previous forecast and something closer to the GFS that
takes the low up the coast, but leaves strong onshore flow and
a surface trough across the area through mid-week. While this is a
stormier pattern for most of the week with the potential for heavy
rainfall, for now it looks like with the position and track of the
low the heaviest rain will stay at sea and across southern and
central Florida. High temperatures should stay in the mid to upper
80s through midweek. Overnight low temperatures will stay in the
mid 70s near the coast, but could drop into the upper 60s to low
70s inland.

&&

.AVIATION...
Scattered afternoon storms expected as a cold front
begins to approach the area. Most of the coverage of storms
expected to be across Se Ga and inland areas of Ne Fl. Have
VCTS beginning aft 18Z at JAX...VQQ...GNV...and SSI. Have
VCSH at CRG and SGJ aft 18Z. The trend will be for any storms
to develop to fade out in the evening.

&&

.MARINE...
A cold front will move across the waters Friday
and stall south of the waters over the weekend. A surface
low is forecast to develop offshore the Florida east coast
and move slowly northeast this weekend. South to Southeast
winds today will shift to the Northeast on Friday and increase
to Small Craft Advisory over the weekend into early next week
due to the tightening gradient between the low and high pressure
to the north. Seas will increase to 5 to 7 feet near shore
and 6 to 9 feet offshore. Scattered showers and storms
expected through the period.

Rip currents: A persistent long period swell will keep a
Moderate Risk of rip currents Friday. An elevated risk is
expected into the weekend as onshore winds and swells are
expected to increase as low pressure develops off the
Florida east coast and moves slowly Northeast.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  94  75  91  73 /  40  40  40  10
SSI  91  78  87  78 /  40  40  40  30
JAX  93  75  90  76 /  40  30  40  20
SGJ  91  77  89  77 /  20  20  40  30
GNV  93  74  91  74 /  40  30  40  10
OCF  93  75  92  74 /  40  30  40  20

&&

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

$$

PP/CE



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