455
FXUS62 KMFL 191728
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
128 PM EDT Thu Sep 19 2024

...New SHORT TERM, AVIATION, MARINE, BEACHES...

.SHORT TERM...
(Rest of today through Friday)
Issued at 120 PM EDT Thu Sep 19 2024

Scattered to numerous showers will be likely across portions of
South Florida this afternoon as as troughing prevails aloft and a
front remains stalled over northern Florida. This is helping pool
moisture over the region as evidenced by MLF`s 12Z sounding which
showed PWATs of 2.02 inches, well above average for this time of
year. The sounding also showed light sfc-3km westerly flow and ample
instability (SBCAPE >2000 J/kg), along with light WSW flow aloft.
Given this setup, expect afternoon sea breeze and outflow boundaries
to become the focal points for deeper confection. The main concern
for today remains heavy rainfall with slow moving storms which could
lead to localized flooding for portions of South Florida. In fact,
the HREF LPMM shows isolated areas along the East Coast metro
possibly getting 4-6 inches of rain, and there are areas that have
already received 2-4 inches of rain over the past couple of days,
which has made for waterlogged soils. To that effect, WPC has
placed most of the East Coast metro under a marginal (1/5) risk
for excessive rainfall this afternoon.

The frontal boundary will slowly drift southward across our region
tomorrow, ushering in some slightly drier mid-level air over the
area. This drier air mass could help limit shower and storm coverage
tomorrow. However, with troughing lingering over the peninsula and
light low level flow, there is still a chance for sea breeze driven
convection to pick up tomorrow afternoon. We kept PoPs in the 40-50%
range.

Although temperatures and heat indices will remain above normal,
convection and cloud coverage should help keep them below advisory
criteria through the period.

&&

.LONG TERM...
(Friday night through Wednesday)
Issued at 310 AM EDT Thu Sep 19 2024

Moving into the upcoming weekend, the upper level trough will
continue to dig southward into the southeastern CONUS. It will
maintain a W/NW flow over the region aloft as the trough`s backside
moves over Florida`s Peninsula. Meanwhile, the plume of moisture
remains over South Florida as the stationary front meanders across
the southern peninsula. Most convection will be driven by the sea
breezes and outflow boundaries, following the afternoon`s diurnal
heating and influence of widespread heavy PWATs (1.7-1.9"). The
primary hazards will be heavy rainfall, strong winds, and localized
flooding, especially over urban areas. While PWATs have dropped
below 2.0", with plentiful moisture and saturated grounds, any slow-
moving storms may lead to flash flooding.

As we move into Sunday and early next week, an expansive ridge will
stretch across the Gulf of Mexico and Florida as the trough moves
into the Atlantic. As this occurs, it will allow for drier air to
advect into the region. Currently, the extended models indicate a
chance for showers, with a drop in PoPs (30-50%) and lower PWATs
(1.4-1.7"), due to this incoming drier air mass. However, further
into the extended, less confidence in the regional impact from rain,
so PoPs are capped at 60% through day 7. This may allow for a drop
below climatological rainfall normals early next week. Looking into
the extended forecast, we will continue to monitor the tropics. In
the upcoming days, the area to watch will be in the western
Caribbean as there is potential for a body of low pressure to form.
The National Hurricane Center`s 2AM outlook has a 40% chance of
tropical formation in the next 7 days. As it remains far too early
for many upcoming details, we will continue to keep an eye on the
latest tropical forecasts.

Temperatures will be near seasonal normals throughout the long term
forecast. Afternoon high temperatures will be in the upper 80s to
low 90 and overnight lows in the 70s. With the potential for daytime
dew points to drop into the low to mid 70s, the drier air may
provide a relief from sticky humidity and heat advisories. However,
with less cloud coverage and lighter rainfall, it will still allow
for oppressive heat and warm temperatures.

&&

.AVIATION...
(18Z TAFS)
Issued at 120 PM EDT Thu Sep 19 2024

Brief periods of MVFR/IFR conditions could be likely for all sites
as slow moving SHRA/TSRA begin to develop. The sea breeze will
begin to work in over the sites around 18Z, and winds could become
gusty within storms and outflow boundaries. Conditions should
begin to improve shortly after sunset, but some stratiform rain
coverage could linger for a few hours after 00Z.

&&

.MARINE...
Issued at 120 PM EDT Thu Sep 19 2024

Winds remain generally light across the coastal waters today as a
weak surface boundary remains just to the north of the area, with
continuing scattered to numerous showers and thunderstorms possible
each day. The boundary reaches the area on Friday, bringing a
decrease in thunderstorm activity through the weekend and into early
next week. However, periods of locally higher seas and gusty winds
may accompany any thunderstorm that forms.

&&

.BEACHES...
Issued at 120 PM EDT Thu Sep 19 2024

Expect minor to moderate coastal flooding to continue during periods
of high tide. These elevated tides will continue to affect all
coastal areas of South Florida through Friday morning, for which a
coastal flood advisory remains in effect. For the upcoming weekend,
a decrease in northerly swell should help reduce the risk for
moderate flooding, but some minor flooding could still be possible.
Additionally, an elevated risk of rip currents could continue for
the Palm Beaches during the next several days.

NAPLES HIGH TIDE TIMES... 1:56 PM today, 1:44 AM tomorrow morning, 2:57PM
tomorrow afternoon

LAKE WORTH HIGH TIDE TIMES...949 PM tonight, 10:24 AM tomorrow morning

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            76  89  76  89 /  50  60  40  40
West Kendall     74  90  73  90 /  50  60  40  50
Opa-Locka        75  90  76  91 /  50  50  40  40
Homestead        75  89  76  89 /  50  60  40  50
Fort Lauderdale  75  88  76  89 /  50  60  40  40
N Ft Lauderdale  75  89  76  89 /  50  60  40  40
Pembroke Pines   75  91  76  92 /  50  50  40  40
West Palm Beach  75  89  76  90 /  50  50  30  30
Boca Raton       75  90  76  91 /  50  60  40  30
Naples           77  90  76  92 /  40  40  30  30

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Advisory until 5 PM EDT Friday for FLZ069-075-168-
     172>174.

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

$$

SHORT TERM...ATV
LONG TERM....JS
AVIATION...ATV