Area Forecast Discussion
Issued by NWS Melbourne, FL
FXUS62 KMLB 280852
Area Forecast Discussion
National Weather Service Melbourne FL
452 AM EDT WED SEP 28 2016
Today-Tonight...Deep offshore flow will exist across the area today
between weak frontal boundary across the southeast U.S. and
subtropical ridge axis south of central Florida. Moisture is
expected to gradually increase through the day and will be
sufficient for scattered showers and storms initially developing
along and out ahead of the west coast sea breeze this afternoon.
This convective activity will shift eastward across the region and
toward the coast later in the day.
Majority of model guidance indicates low level offshore flow will
range around 7-10kts, which should be weak enough to allow the east
coast sea breeze to form. However it will likely be delayed and
stall near the coast. Any storms or boundaries that interact with
the sea breeze will enhance thunderstorm activity along the coast,
with a few stronger storms forming and pushing offshore. 500MB temps
around -8C and some drier air in mid levels will support potential
for frequent lightning, small hail and gusty winds up to 40 to 45
mph in any stronger storms.
Highs will generally reach the upper 80s to around 90 degrees, but
with a delayed sea breeze and sufficient daytime heating temps could
be a few degrees warmer along the coast. Low overnight will be in
the low to mid 70s.
THU...00Z GFS shows mid level cut-off low over the Ohio Valley
forcing a frontal boundary into the deep south/Gulf coast.
Deepening W-SW flow ahead of the boundary will at least delay the
onset of the east coast sea breeze as 850 mb winds increase near 15
knots which is close to the threshold for preventing the sea
breeze from forming. Despite some cloudiness, temperatures will be
at least a couple degrees above normal reaching near 90 at the
coast and upper 80s interior. With precipitable water values just
under 2 inches and 500 mb temps cooling near -9C, expect scattered
aftn storms to push E/NE across the area.
FRI-TUE...The frontal boundary is forecast to stall over north
Florida on Fri, then retreat northward this weekend as upper low
slowly lifts up to the Great Lakes and Atlantic ridge builds back
over the area. 00Z GFS has continued to back off on the amount of
drying that pushes into central Florida on Fri so have raised PoPs
to 40-50 percent with afternoon storms. Offshore (SW) flow will
continue but not quite as strong so the east coast sea breeze
should be able to develop and push across the coastal counties at
Onshore (east) flow is forecast to develop this weekend and with
no significant drying, scattered showers and storms are forecast
each day. Highs are expected to continue to reach the upper 80s
over much of the area each day with lows generally in the low 70s,
except upper 60s possible in Lake/Volusia counties.
Tropics...NHC and the suite of 00Z models are forecasting a
tropical cyclone to develop in the eastern Caribbean later today,
moving west or west northwest. The message for now is that we
remain in peak hurricane season and it is too early to say if this
system will have an impact on east central Florida.
.AVIATION...Mainly VFR through the morning. Then Tempo IFR/MVFR
conds will occur in scattered showers and storms moving east to
northeast across the region into the afternoon. East coast sea
breeze should develop and briefly switch winds to the E/SE at
coastal TAF sites before storms reach the coast and push offshore
late in the day.
Today/Tonight...Stalled frontal boundary over the southeast U.S.
will keep W/SW winds over the waters, with winds speeds around 5-10
knots today and up to 10-15 knots offshore tonight. Winds near the
coast may briefly back to the S/SE with sea breeze development later
in the afternoon. Seas up to 2-4 feet today will become 3 feet or
less into tonight.
Main concern for boaters today will be with scattered offshore
moving storms into the afternoon and early evening hours, producing
gusty winds and frequent lightning strikes.
THU-SUN...Frontal boundary across the Southeast U.S. expected to
reach north FL Thu-Fri before retreating northward this weekend.
W/SW winds up to 10-15 knots expected over the waters Thursday and
then flow weakens into Friday before becoming onshore into the
weekend as front lifts back northward and fades. Seas will range
from 2-4 feet through the period. Longer period ocean swells will
keep a moderate risk of rip currents into the weekend.
.PRELIMINARY POINT TEMPS/POPS...
DAB 90 72 89 71 / 50 30 50 20
MCO 90 72 88 72 / 50 20 50 20
MLB 90 73 90 73 / 50 30 50 30
VRB 90 72 90 72 / 50 30 50 30
LEE 89 74 87 72 / 50 20 50 20
SFB 90 73 89 73 / 50 20 50 20
ORL 90 74 88 73 / 50 20 50 20
FPR 90 72 90 72 / 50 30 50 30