Heavy Rain in Florida, August 11, 2017

Area Forecast Discussion
National Weather Service Jacksonville FL
342 PM EDT Fri Aug 11 2017

.NEAR TERM.../THROUGH SATURDAY/...

A weak low offshore the Flagler County coast will continue to move
slowly north and be just offshore the extreme Ne Fl coast by late
this evening before opening up as wave as it gets absorbed by a
short wave trough that is covering much of the eastern U.S.
Convergent bands rotating around the low made it to the coast and
merged with the east coast seabreeze. Concern will be for training
of cells just inland from the Flagler and St Johns coast where
rainfall amounts greater than 2 inches could cause localized
flooding. The trend will be for scattered storms to spread inland
during the late afternoon and eve as the west and east coast
seabreezes advance inland and merge between I-75 and U.S. 301. Some
storms may also move east back towards the Flagler and St Johns
coast this eve before dissipating as the low moves further north and
steering winds begin to shift to the northwest.

On Saturday...the Bermuda ridge begins to build into south Fl while
a cold front advances into the southeast U.S. which helps deepen
southwest winds. With a moist and unstable southwest
flow...scattered storms expected to develop along the seabreezes
with best coverage of storms along seabreeze merger just west of I-
95 in the afternoon/early eve. Some storms may become strong...due
to afternoon heating...and produce strong and gusty winds in
addition to frequent lightning and locally heavy rain.

.SHORT TERM /Saturday Night Through Sunday Night/...

Weak upper troughing will remain across the northern and eastern
conus through the short term. An upper trough centered north of the
Lower Great Lakes will shift east and northeast, with various
shortwaves moving across the middle of the country reinforcing the
weak troughing. Upper ridges will be located east of Bermuda and
over Texas, with the ridge axis located south of the region. At the
surface, a stalled frontal boundary will be near northern Georgia,
with a broad trough of low pressure over Georgia and Alabama. Light
southwesterly flow will prevail. A tropical wave east of the Bahamas
Saturday night will lift northwest and then northward around high
pressure on Sunday and Sunday night, well to the east of the U.S.

A few showers/storms may linger across the eastern portion of the
region Saturday evening, ending before midnight. Mainly quiet
conditions are then expected overnight with lows in the 70s. The
light southwesterly flow will make the Gulf coast sea breeze
dominant on Sunday, with scattered to numerous showers and storms
moving into the Suwannee Valley in the late morning and early
afternoon, and then spreading northeast across southeast Georgia
closer to the trough of low pressure. A weak east coast sea breeze
is forecast to develop, with scattered storms developing along it in
the late afternoon to early evening before dissipating. Highs are
forecast to be generally in the lower 90s. Lows will be in the 70s.

.LONG TERM /Monday Through Friday/...
The models still differ in the midweek to end of the week period.
Weak ridging aloft is expected over the region early next week, with
a frontal boundary over northern Georgia. By the middle of the week,
the GFS still digs a trough southward along the eastern seaboard.
The ECMWF is much weaker with the trough and keeps ridging over to
just west of the region. Expect high end scattered to numerous
diurnally driven showers and storms each afternoon and early
evening. Highs will generally be in the lower 90s, except upper 80s
near the coast. Lows will be in the 70s.

&&

.AVIATION...Scattered showers and storms expected to develop
as seabreezes slowly advance inland. Have VCTS at all Ne Fl
terminals til 00Z. Amendments may be needed for TSRA especially at
SGJ.

&&

.MARINE...A weak low off the Flagler coast will move north
to just offshore the extreme Ne FL coast by late this eve before
opening up as a wave. Northeast winds 10 knots quickly become south
to southwest 10 to 15 knots tonight into early next week as a
Bermuda ridge builds just south of the waters. Scattered showers and
storms. A trough of low pressure north of Puerto Rico will move
northwest and may organize to the east of the Bahamas this weekend
but this system should eventually turn northward well to the east of
the waters by late in the weekend.

Rip Currents: A Moderate Risk is expected through the weekend due to
persistent groundswell.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  75  93  76  93 /  30  50  20  60
SSI  77  89  78  90 /  20  40  30  40
JAX  75  93  76  93 /  20  50  30  60
SGJ  76  92  76  91 /  30  50  30  50
GNV  75  92  74  91 /  40  40  10  50
OCF  75  92  75  91 /  40  40  20  40

&&

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

&&

PP/AK/NM

Hazardous Weather Outlook...UPDATED
National Weather Service Jacksonville FL
1049 AM EDT Fri Aug 11 2017

AMZ450-452-454-470-472-474-FLZ020>025-030>033-035>038-040-124-125-
GAZ132>136-149>154-162>166-120900-
Coastal waters from Altamaha Sound to Fernandina Beach FL out
20 NM-
Coastal waters from Fernandina Beach to St. Augustine FL out
20 NM-
Coastal waters from St. Augustine to Flagler Beach FL out 20 NM-
Waters from Altamaha Sound GA to Fernandina Beach FL from 20 to
60 NM-
Waters from Fernandina Beach to St. Augustine FL from 20 to 60 NM-
Waters from St. Augustine to Flagler Beach FL from 20 to 60 NM-
Hamilton-Suwannee-Columbia-Baker-Inland Nassau-Inland Duval-Union-
Bradford-Clay-St. Johns-Gilchrist-Alachua-Putnam-Flagler-Marion-
Coastal Nassau-Coastal Duval-Coffee-Jeff Davis-Bacon-Appling-
Wayne-Atkinson-Ware-Pierce-Brantley-Inland Glynn-Coastal Glynn-
Echols-Clinch-Charlton-Inland Camden-Coastal Camden-
1049 AM EDT Fri Aug 11 2017

...WATER SPOUTS POSSIBLE ALONG THE LOWER NORTHEAST FLORIDA
COAST TODAY...

...MODERATE RISK OF RIP CURRENTS AT AREA BEACHES TODAY...

This Hazardous Weather Outlook is for Northeast Florida,
Southeast Georgia and the Adjacent Coastal Waters.

.DAY ONE...This afternoon and and Tonight...

A weak low will track just offshore the coast and produce scattered
storms along the lower northeast Florida coast through mid
afternoon. Scattered storms are also expected across inland areas
late afternoon into the evening.  Isolated storms will be possible
and produce strong gusty winds...frequent lightning... and locally
heavy rain in excess of 2 inches which may cause temporary
flooding in low lying areas. Water Spouts will be possible along
the Flagler and St Johns county coasts through mid afternoon.
Storm motion will generally be south to southwest at 5 to 10 mph.

There is a moderate risk of rip currents along area beaches today.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday...

Scattered to numerous mainly afternoon and evening thunderstorms
are expected over the weekend and into next week. A few strong
storms will be possible in the afternoon and early evening hours
with gusty winds and heavy rainfall potential.

A low end moderate risk of rip currents is possible along area
beaches on Saturday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated at this time.

For additional information, visit the National Weather Service in
Jacksonville website on the internet at weather.gov/jax.