Special Weather Statement, NWS Melbourne, FL

Area Forecast Discussion
National Weather Service Melbourne FL
359 PM EDT Thu Aug 20 2020

.DISCUSSION...
Thru Tonight...Several pockets of convective initiation in the early
afternoon will bring gusty winds, frequent lightning and heavy rain
across the Treasure and Space Coast, as well as the I-4 corridor
southwest of Orlando. While strong to potentially severe
thunderstorms are still anticipated, the driving mechanisms seem to
be a little less impressive based on the 15Z sounding, with temps
aloft above -7, PWAT decreasing to 1.64" and DCAPE of 713 J/kg. With
sufficient heating after dissipation of earlier broken cirrus and
the east coast breeze advancing inland, additional strong storms are
likely to develop even without robust conditions aloft, especially
as present outflow boundaries move towards the east. Essentially,
much uncertainty still rests in the evolution of the next few hours,
with conditions in the mid levels not favorable for strong storms,
although radar trends continue on an upward rise, with numerous
showers and storms developing and will continue to over the next few
hours. Confidence is low in timing of precipitation clearing this
evening as well, with current storm movement and progress across the
interior not supportive of activity persisting past sunset, with
most storms strengthening along the coast in the sea breeze
interaction; however meso models keep a broad area of precip and
embedded thunderstorms across most of the forecast area past
midnight. Tonight's forecast favoring the persistence trend, keeping
30% chance over land areas a bit past sunset, and a 20% chance just
at the coast beyond midnight.

Fri-Sat...(modified previous) The Atlantic ridge axis will move
north to across the central FL peninsula on Fri, then lift further
north on Sat. This will act to gradually deepen onshore flow.
Early morning SWRLY surface flow will become more S/SE during the
day on Fri/Fri night and then SE/E on Sat. Storm steering flow on
Fri will be out of the S/SW and S/SE on Sat. This will gradually
favor interior areas for highest PoP coverage. Keeping 60-70 PoPs
for Fri areawide, and 40-60 PoPs on Sat with highest numbers
across the I-4 corridor and interior; lowest near the Treasure
Coast. Highs in the U80s to 90 near the coast and L90s interior.
Lows generally in the 70s areawide.

Sun-Wed...The Atlantic ridge axis continues north of the area as
Tropical Depression 13 (TD13) cruises WNW near the Greater Antilles
and towards the FL Straits/Keys Sun overnight-Mon. Much
uncertainty in track and intensity is present in regards to this
system and relative impacts to east central FL, so residents and
visitors should continue to monitor the unfolding situation and
the latest forecast from the National Hurricane Center. As of now,
differences reside in global model solutions, but the general
consensus is for the system to make its approach to the southern
Bahamas early Monday, rapidly pushing NW to the southern FL
peninsula by late Monday/early Tuesday. As we monitor the
progression of TD 13, the current forecast keeps high PoPs
(70-80%) beyond Sunday through midweek, with seasonal temps in the
lower 90s in the afternoon, low 70s overnight.

&&

.AVIATION...
Highest storm coverage through this evening generally south of an
ISM-TIX line where TEMPO IFR/MVFR restrictions from storms can be
expected. Some other boundaries may still develop convection farther
north, but the cloud cover may keep coverage lower from MCO
northward. Expecting an earlier end to convection across inland
sites (approx. 23Z-00Z) and a little later toward the east coast
(00Z-01Z).  VFR conditions will prevail overnight with BKN/OVC mid
and high level clouds gradually decreasing from late evening
onward.

&&

.MARINE...
Current-Tonight...Fast moving showers and thunderstorms developing
along the coast will move towards the northeast at around 15
knots through the late evening. As storms over the interior reach
the east coast sea breeze, intensification is expected, with wind
gusts in excess of 35 knots possible along the nearshore Atlantic
waters generally south of Cape Canaveral. SE winds near 10 knots
will return to S/SW after the sea breeze circulation diminishes
tonight with seas of 2-3 ft.

Fri- Fri Night...The Atlantic ridge axis will move back north to
across the local waters during the day on Fri- Fri evening. S/SW
morning winds will back a bit to the SSE/SE thru the period.
Speeds AOB 12 kts. Seas generally 2-3 ft and up to 4 ft well
offshore north of Sebastian Inlet. Strong afternoon/evening storms
remain in the forecast across the intracoastal and near shore
Atlc waters. Winds and seas locally higher near storms.

Sat-Mon...The Atlantic ridge axis will continue to advance northward
on Sat and into early next week. This will gradually deepen onshore
flow across the area through this weekend and into Mon. TD13 will
move across the Caribbean and towards the south FL peninsula Sun
overnight and into Mon. Onshore-moving, gusty squalls, will increase
in coverage/intensity during the day on Sun and thru Mon. Seas
generally AOB 4 ft thru the day on Sun will build as the system
approaches. Latest track trend builds seas 5-6 ft nearshore on
Monday and up to 8 ft in the offshore zones, peaking near 10 ft
Monday night then diminishing as it shifts across the state and
into the Gulf waters. As of now, SE winds will max out at 20 knots
late Mon/early Tue, keeping in mind that strength and exact track will
play a role for both winds/seas heading into late weekend and
early next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
DAB  75  89  76  89 /  40  60  40  60
MCO  75  90  75  91 /  30  70  40  60
MLB  76  89  77  89 /  40  60  30  50
VRB  76  89  75  89 /  40  50  20  50
LEE  75  90  74  91 /  30  70  40  60
SFB  75  91  75  91 /  30  70  40  60
ORL  75  91  75  92 /  30  70  40  60
FPR  76  90  75  89 /  40  50  20  50

&&

.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&

Smith/Weitlich/Combs