Damaging Wind and Heavy Rain in Florida, July 16, 2018

Area Forecast Discussion
National Weather Service Jacksonville FL
312 AM EDT Mon Jul 16 2018

...WET PATTERN CONTINUES...

.NEAR TERM.../Today and Tonight/...

Surface observations showing a few areas across southeast GA and
northeast Fl are experiencing shallow fog which is reducing
visibility to about 3-5 miles. Trends in the visibility will be
watched over the next few hours, but visibility should quickly
improve after sunrise.

For today, another good chance of seeing widespread showers and
thunderstorms across the area, especially southeast GA and I-95
corridor. The biggest change for today is the mean flow of the
atmosphere. By afternoon, sfc to 700 mb will be west-southwest.
Despite the flow remaining weak, the flow will help push the Gulf
coast sea- breeze eastward while holding the East coast sea-
breeze along the coast/I-95 corridor. Along with the southwesterly
steering flow, a weak and broad upper-level trough will be digging
into the Southeast. This will assist thunderstorm development
across southeast GA. Throughout the afternoon, thunderstorms
should slowly move eastward, producing gusty winds and heavy rain
along the way. Forecast soundings continue to indicate very deep
moisture content of over 2". Lack of environmental shear will
promote pulse convection which collapses and producing outflow
boundaries. By late afternoon, The I-75 corridor from Lack City
down to Ocala likely dries out to mostly isolated activity. The
I-95 corridor will become the focus for new thunderstorm
development as outflow and sea-breeze boundaries collide during
the late afternoon and evening hours. With the slow storm motions,
this expectation could be realized later in the day, keeping
showers and thunderstorms around the I-95 corridor into the early
evening hours. This potential has been acknowledged in the
forecast, but could change evolve tomorrow if this transpire more
quickly.

With the conditions discussed above, precipitation remains in the
forecast throughout the overnight period, although coverage will
be greatly reduced. Southwesterly flow ahead of a frontal pattern
results in continued precipitation chances Monday morning,
primarily for southwest zones near the Gulf Coast.

.Short Term.../Tuesday and Wednesday/...

Upper level troughing over the forecast area will be the dominant
driving force for Tuesday and Wednesday with the potential for
excessive rainfall, particularly over southern Georgia. Models
show surface level shortwaves moving through the area on both
Tuesday and Wednesday which, in tandem with the standard daytime
heating, could result in the strong thunderstorms that that could
be capable of producing a significant amount of rain which, even
though the prevailing flow will allow storms to move faster than
it had in previous days, could still pose a risk to areas that
have already received a good amount of rain earlier in the week.
The direction of the flow will be a result of the upper level
trough forming in the north and ridging building in the southeast
from the Bermuda high, resulting in the expected flow during this
period to be predominantly out of the southwest. This will help
to strengthen the west coast seabreeze and severely diminish the
eastern seabreeze, resulting in storms developing along the
eastern shore later in the day as the two flows meet.

High temperatures are expected to be in the low 90s during this
span, with low overnight temperatures dropping into the low 70s.

.Long Term.../Thursday through Sunday/...

Conditions are going to be very wet over the course of the week.
Prevailing flow will shift to more out of the southwest with the
models forecasting a mid level low forming over north central
Florida between Friday and Saturday. Very high amounts of
precipitable water are associated with the passage of the low,
with any reductions in moisture in the atmosphere being dispelled
as the westerly flow resumes and brings in moist air from the
Gulf.

Max and min temperatures will be consistent for the forecast area
up to the end of the week, with highs in the low 90s and
overnight lows in the low 70s.

.AVIATION...

Once again this morning, some TAF sites are seeing restricted
visibility associated with the radiationally driven fog.
Otherwise, TAF sites have prevailing VFR conditions. Southwesterly
steering flow tomorrow will result in earlier potential for
showers/thunderstorms for GNV tomorrow. TAF sites along the east
coast will see isolated activity during the afternoon, followed by
higher probabilities during the late afternoon and evening time
frames. Southwesterly winds of the Gulf of Mexico may result in
lower ceilings for GNV Tuesday morning, but will wait for higher
confidence in later TAF packages.

&&

.MARINE...

As a frontal trough moves in from the northwest, pressure gradient
increases slightly resulting in 10-15 knot southerly winds over
the waters today. Abundant moisture remains so expecting another
day of showers and thunderstorms, especially later in the day for
near-shore waters. Throughout the rest of the week, frontal trough
settles in over the Southeast, promoting persistent southwesterly
flow of 10-15 knots over the waters. Showers and thunderstorms
remain in the forecast throughout the week as well.

Rip Currents: Moderate risk of rip currents at all beaches Monday.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  92  74  90  73 /  60  50  70  20
SSI  89  77  89  77 /  40  60  70  30
JAX  93  75  92  75 /  60  60  60  30
SGJ  92  75  91  75 /  60  60  50  40
GNV  92  74  91  74 /  40  40  50  40
OCF  92  74  89  74 /  30  50  50  40

&&

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

McGinnis/Corless/Enyedi