Flood and Heavy Rain in Florida, July 7, 2018

Area Forecast Discussion
National Weather Service Jacksonville FL
827 AM EDT Sat Jul 7 2018

...LOCALIZED FLOODING POTENTIAL TODAY...

.UPDATE...

TUTT was rotating westward over Apalachee Bay this morning with
early morning cloud cover along and west of the I-75 corridor.
This cloud cover will delay the onset of the west coast sea breeze
front. Mostly sunny skies prevailed across the remainder of the
forecast area with a fairly weak low level pressure pattern in
place between high pressure across south FL and a weak surface
trough north of the Altamaha River basin, which was sliding
southward around the western periphery of TD#3. The 12Z JAX RAOB
continued to show elevated moisture content across the local area
with PWAT at 1.89 inches, slightly above normal, while the mid
levels of the atmosphere were a tad more stable compared to
yesterday with warming around 500 mb where temps were 8.3 deg C as
the TUTT low continued to push farther west, away from the First
Coast. East coast and St. Johns river breeze convection expected
to develop by midday, with very slow progress inland as storm
motion will be quite weak and erratic under 1000-500 mb trough
axis between departing TUTT and TD#3. Expect to see deeper
convective growth by early afternoon near the I-75 corridor where
a differential heating boundary will likely develop between
departing TUTT cloud cover and inland warming, which will be
similar to west coast sea breeze convective line. These bands of
convection and outflows will slowly progress farther inland across
the interior of NE FL and south GA in the vicinity of the
Okefenokee NWR into the mid to late afternoon, with the main
convective hazards including wet downbursts, excessive lightning
and localized flooding rainfall. Convection expected to drift
toward the Altamaha River basin late afternoon into the early
evening associated with the surface front edging southward. Plenty
of low level convective forcing mechanisms in place as well as
surface based instability and deep layer moisture to continue with
elevated rain chances, but given increasing stability in the
mid/upper levels with warming temps in the wake of the departing
TUTT, severe storms not as probable as yesterday. The Weather
Prediction Center advertised parts of SE GA as under a Marginal
Risk for Excessive Rainfall which could promote flooding potential
along and near the surface front

Temperatures will trend near normal with highs in the upper 80s
to low 90s with heat index values in the upper 90s.

.AVIATION...12Z TAF period...

Restrictions expected this afternoon due to passing showers and
tstorms. Best tstorms chances will focused inland specifically at
JAX, VQQ and GNV in the afternoon and evening. Very slow storm
motion will favor an extended period of restrictions if convection
impacts terminals. Light and variable winds 6 kts or less this
morning will transition along the coast at SSI, CRG and SGJ to ESE
with east coast sea breeze this afternoon with speeds 10-15 kts.

.MARINE...

No headlines with light offshore flow over the waters this
morning 10 kts or less with seas increasing as swells from TD#3
increase within the waters from TD#3, offshore of the Carolinas.
Combined seas expected to be less than 3 ft today. East coast sea
breeze convection expected to fire near the coast by early
afternoon, with slow progression inland as winds over the adjacent
waters transition to ESE 10-15 kts.

Rip Currents: Low risk today. Lifeguard reported more numerous
sandbars and sloughs that will tend to funnel seaward retreating
water and thus create a small scale rip current threat.

&&

.PRELIMINARY POINT TEMPS/POPS...
AMG  91  72  89  72 /  60  50  60  30
SSI  88  76  86  76 /  20  10  40  30
JAX  91  72  90  73 /  50  20  50  20
SGJ  88  73  88  74 /  30  10  30  20
GNV  91  71  91  73 /  60  30  50  30
OCF  89  72  90  73 /  50  30  30  20

&&

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

Enyedi/Bricker