251
FXUS62 KMFL 151328
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
928 AM EDT Sun Sep 15 2024

...New UPDATE...

.UPDATE...
Issued at 907 AM EDT Sun Sep 15 2024

A weak frontal boundary will remain nearly stationary today over
the Lake Okeechobee region. This will keep a south/southwest
steering flow over South Florida today allowing for the west coast
sea breeze to push eastward across the region with the east coast
sea breeze remaining over the east coast metro areas. This in turn
will allow for scattered to numerous showers and thunderstorms to
develop this afternoon with the focus over the eastern half of
South Florida this afternoon into early even hours. The current
forecast show this weather pattern and no changes are plan for the
POPS across South Florida today.

There could be a couple of strong storms this afternoon over the
east coast metro areas where the sea breezes collide. Primary
impacts will be lightning strike, gusty winds up to 50 mph, and
locally heavy rainfall.

Forecast highs today will be in the lower to mid 90s over most of
South Florida with dew points in the mid to upper 70s. This will
allow for the heat indices be in the 105 to 110 range over most of
South Florida, except for Glades and Hendry Counties where it will
be 100 to 105. Therefore, the Heat Advisory will remain in effect
today for most areas except for Glades and Hendry Counties.

Rest of the forecast looks good at this time and no other changes
are planned.

&&

.SHORT TERM...
(Today through Monday)
Issued at 219 AM EDT Sun Sep 15 2024

A Rex Block (high over low) synoptic pattern will set up over the eastern US
for the short-term period, with the closed low beginning to pivot southward
today into Monday which should erode the ridge that has been in place over
the SE Gulf the last several days. At the surface, an area of low pressure
will develop along the stalled Atlantic frontal boundary today, with this
low then lifting northward into the vicinity of the Carolinas by Monday
(with some chance of it obtaining tropical characteristics over the Gulf
Stream). We will remain positioned south of this boundary and associated
low, with generally weak W-SW flow prevailing over SFL.  The flow is weak
enough that it should allow for limited inland progression of the east
coast sea breeze this afternoon. Some drier mid-lvl air will be drawn
southward into the area today, bringing PWATs closer to climo (around 2
inches) and this combined with the continued warm temperatures aloft should
make convection a bit more anemic/less widespread than previous days. The
highest rain chances should still be over Interior and SEFL with a general
eastward progression of convection with time.

The mid-lvl low will pivot southeastward towards the area on Monday with
some low amplitude shortwave energy also approaching the area and mid-lvl
temperatures cooling a couple of degrees. Rain chances will be highest over
southern portions of the area due to both the W-NW mean low-level flow, and
the generally higher PWATs over the southern half of the area. PoPs should
be near climo with storms remaining fairly "garden variety" in terms of
threats, i.e. gusty winds and locally heavy rainfall.

Peak heat indices may drop a couple degrees today relative to
Friday/Saturday but will still likely run in the 105-111 degree range over
the area, and a heat advisory is in effect for all of SFL apart from
Glades/Hendry counties. Conditions look more marginal on Monday with peak
heat indices right around the 105 degree mark. Highs should remain just
above seasonal normals, i.e. generally in the low 90s with lows largely in
the mid to upper 70s.

&&

.LONG TERM...
(Monday night through Saturday)
Issued at 219 AM EDT Sun Sep 15 2024

The stagnant/blocking pattern will remain in place over the eastern US
through the week with SFL generally lying along the southern periphery
of the eastern US trough. The surface gradient will remain light favoring
sea-breeze driven winds through much of the week. PWATs will largely
remain in the 1.8 to 2.1 inch range (near to just above climo) through
mid-week although similar to Monday there could be some spatial variation
within our area depending on the positioning/orientation of the tropical
moisture plume. This setup will generally favor near to slightly above
normal rain chances through most of the period (largely 40 to 60% range),
with the main question marks being the timing of any shortwaves which
pivot into the area,and where the max PWATs align. Temperatures and
heat indices will be near to just above normal through the period (highs
in the upper 80s to low 90s).

The center of the closed low/trough may shift southward closer to the area
late next week into next weekend which would result in cooler temperatures
aloft, drier air, and perhaps even some cooling at the surface, but as is
typical with blocking patterns and cut-off lows, confidence in this
evolution is low.

&&

.AVIATION...
(12Z TAFS)
Issued at 708 AM EDT Sun Sep 15 2024

Winds will be mostly south/southwest today at 5 to 10 knots over
the TAF sites, except for KFLL where it should become S/SE in the
afternoon hours. VCTS for all of the TAF sites between 18Z and 00Z
except for KAPF where VCSH for most of today. Ceiling and Vis in
VFR conditons but should fall down into MVFR with possible IFR
conditions in the showers and thunderstorms this afternoon.

&&

.MARINE...
Issued at 219 AM EDT Sun Sep 15 2024

Generally light south to westerly winds will prevail through early next
week as a frontal boundary and associated low pressure remain north of the
area. Seas over the Gulf waters will generally be 2 feet or less with seas
increasing today into Monday over the Atlantic waters as northerly swell
generated by low pressure off the SE Coast moves in. Scattered showers and
thunderstorms will be possible each day through the period and could lead
to locally higher winds and seas.

&&

.BEACHES...
Issued at 219 AM EDT Sun Sep 15 2024

Lingering northerly swell will result in a moderate risk of rip
currents along Palm Beaches today. The rip risk will likely increase early
next week over the Atlantic beaches as higher amplitude northerly swell moves in.

From today through the middle of the week, there will be the
potential for minor coastal flooding around periods of high tide due to
astronomically higher tides associated with this full moon. A Coastal Flood
Statement is in effect through at least Wednesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            93  78  92  78 /  60  20  50  30
West Kendall     93  76  92  76 /  60  20  50  30
Opa-Locka        93  78  92  78 /  60  20  50  30
Homestead        92  78  91  78 /  60  20  50  40
Fort Lauderdale  92  78  90  78 /  60  20  50  40
N Ft Lauderdale  93  78  92  78 /  60  20  50  40
Pembroke Pines   93  78  94  78 /  60  20  50  30
West Palm Beach  93  78  92  78 /  50  20  40  30
Boca Raton       92  78  93  78 /  60  20  50  40
Naples           90  79  90  78 /  30  10  20  20

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory until 6 PM EDT this evening for FLZ067>075-168-
     172>174.

AM...None.
GM...None.
&&

$$

SHORT TERM...Carr
LONG TERM....Carr
AVIATION...BNB