675
FXUS62 KMLB 191859
AFDMLB

Area Forecast Discussion
National Weather Service Melbourne FL
259 PM EDT Thu Sep 19 2024

...New DISCUSSION, MARINE, HYDROLOGY...

.DISCUSSION...
Issued at 255 PM EDT Thu Sep 19 2024

Key Messages:

- Showers and storms continue through mid evening, decreasing
  rain chances as a front settles south of the area this weekend

- High astronomical tides promote minor coastal flooding into this
  weekend, particularly during late morning high tides

- A medium chance for tropical development next week remains in
  the northwest Caribbean and Gulf of Mexico

Now-Tonight...An earlier start to showers and lightning storms is
under way this afternoon. Activity is generally moving to the east
around 15 mph, and the highest coverage of rain so far extends from
Lake Okeechobee to the Treasure Coast. Coverage of showers and
storms is expected to continue increasing this afternoon through
early evening, before activity gradually dissipates by mid to late
evening. RAP analysis shows 1000-2000 J/kg of MLCAPE areawide with
very weak mid level lapse rates. Despite slightly more supportive
500mb temps around -6C to -7C, updrafts will struggle to maintain
any formidable strength. Additionally, PW are lower across the
northern half of the area (1.5-1.6"), compared to values around 1.9-
2.0" over locations from Osceola and southern Brevard southward. All
of this is to say, the environment is supportive of brief heavy
downpours, gusty winds up to 45 mph, and occasional lightning
strikes. Even a brief funnel cloud along boundary collisions cannot
be ruled out. However, stronger activity will likely be held back by
the limiting environmental conditions today.

As rain winds down later this evening, temperatures will retreat
from the 80s to the mid 70s overnight. Sky conditions are expected
to improve west to east, and similar to the past couple of
mornings, some patchy fog is possible over northern Lake and Volusia
counties into Friday morning.

A reminder that a high risk of rip currents remains at the Volusia
and northern Brevard County beaches, along with a moderate risk of
rip currents at the southern Brevard County and Treasure Coast
beaches through tonight. Additionally, a Coastal Flood Advisory
continues with minor flooding of low-lying areas along the shoreline
possible, especially around times of high tide (10 PM tonight).

Friday-Saturday...Coastal flooding concerns increase around times
of high tide, especially the mid morning high tides, late this
week into the weekend. A Coastal Flood Advisory remains in effect
through Saturday afternoon, and it is possible that this will
need to be extended further into the weekend. Some flooding of
low-lying areas along the shoreline, potentially leading to
instances of road closures, is possible.

A weak surface boundary settles well south of the area on Friday,
allowing drier northerly flow to overspread north central Florida.
This forecast reflects a shift to the drier weekend pattern,
beginning Friday afternoon, with 15-25 PoP north and 30-40 PoP
from Melbourne south to Lake O and the Treasure Coast. Slightly
higher moisture in these locations will allow for a little better
coverage of showers and a few lightning storms. Similarly on
Saturday, 15-25 PoP is in place for much east central Florida, as
weaker marine showers approach the coast and any development along
the inland-moving sea breeze stays rather isolated. Temperatures
both days will top out in the upper 80s to low 90s, but with lower
humidity, heat index values are expected to remain below the 100
degree mark. Overnight lows return to the low 70s inland to the
mid 70s along the coast.

Sunday-Wednesday...As upper ridging builds east over the Gulf
Coast and southeast U.S. late weekend into early next week, a lot
of questions remain regarding our next chance at widespread
measurable rainfall. Monday and Tuesday look to be the driest with
only 15-20 PoP, and depending on what happens across the northwest
Caribbean early to mid week (if anything), we will stay in a drier
pattern until deeper, southerly moisture makes a return to the
state. As outlined by the National Hurricane Center, a medium
chance for tropical cyclone development in the next 7 days over
the northwest Caribbean and south-central Gulf of Mexico. Models
continue to waver on a myriad of solutions, so for now, continue
to monitor the latest forecasts. Highs each day into next week are
forecast to remain near or slightly above mid-September normals,
with lows around typical values (low 70s) for this time of year.

&&

.MARINE...
Issued at 255 PM EDT Thu Sep 19 2024

Now-Tonight...Seas will continue to fall into tonight, around 2-4
ft, as onshore flow becomes light and variable through daybreak
Friday. Scattered showers and lightning storms will continue to
push over the waters through the evening and may last through the
early overnight period. Locally higher wind gusts and seas are
possible as a result of this activity.

Friday-Monday...Generally favorable conditions are forecast
through the weekend with poor boating conditions potentially
returning by Sunday or early next week. Persistent northeasterly
winds will increase each day with the highest gusts 15-20 kt in
the afternoon and evening hours. Seas 2-3 ft thru Saturday,
increasing to 3-5 ft Sunday-Monday.

&&

.HYDROLOGY...
Issued at 255 PM EDT Thu Sep 19 2024

The Saint Johns River at Astor is forecast to remain in Moderate
Flood stage through at least the upcoming weekend. The potential
exists for small additional rises if locally heavy rainfall develops
over the river basin. Farther upstream, the Saint Johns at Deland
and Sanford will remain near or slightly above Action Stage.

&&

.AVIATION...
(18Z TAFs)
Issued at 130 PM EDT Thu Sep 19 2024

Increasing shower and storm coverage is forecast through the
remainder of this afternoon and into the evening hours as the east
coast sea breeze moves inland and collides with the west coast sea
breeze. Activity has already started across the Treasure Coast
terminals, with TEMPOs between 18-21Z. Guidance is hinting at a
later collision across the interior terminals, so have started
TEMPOs later, between 22-01Z. The TEMPOs are for VIS and CIG
reductions to MVFR due to TSRA, though drops to IFR cannot be
ruled out. Will continue to monitor and amend as needed. Activity
will linger into the evening as activity gradually moves offshore,
with conditions improving after 00Z. VFR conditions are forecast
through the overnight hours with winds becoming light and
variable. Winds pick back up out of the NE after 15Z between 5 to
10 knots.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  73  88  74  88 /  10  20  10  30
MCO  74  90  74  90 /  30  20   0  30
MLB  74  88  74  88 /  30  30  10  20
VRB  73  89  74  89 /  30  40  10  20
LEE  74  90  73  90 /  20  20   0  20
SFB  73  89  73  89 /  20  20   0  30
ORL  74  90  74  90 /  30  20   0  30
FPR  72  88  73  89 /  30  40  10  20

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Advisory until 2 PM EDT Saturday for FLZ141-154-
     159-164-347-447-647-747.

AM...None.
&&

$$

DISCUSSION...Schaper
AVIATION...Tollefsen