Special Marine Warning 460, NWS Miami, FL

Area Forecast Discussion
National Weather Service Miami FL
229 PM EDT Sat Sep 11 2021

.DISCUSSION...

Short Term (Today through Sunday)...

South Florida has transitioned to an easterly flow pattern with
today serving as a transition day as some relatively drier air has
moved over the region. The convective focus is expected to be
mainly around boundary collisions as the easterly flow has pinned
the Gulf sea breeze over Southwest Florida. Cannot rule out a
strong storm or two this afternoon but convection should be more
muted today than in previous days.

The surface ridge axis sitting to the north of the area will keep a
persistent easterly flow overnight. Easterly wind surges are
possible, particularly as increasing moisture arrives from the
Bahamas. As this moisture arrives, shower and thunderstorm chances
will increase from east to west overnight into Sunday. The enriched
moisture (2+ inch precipitable water values) will also allow a
return for heavy rain chances across the area. Adjusted temperatures
a few degrees cooler compared to some guidance along the east coast
to account for the increased cloud cover, moisture, and rain-cooled
air chances.

Long Term (Sunday night - Friday):

Models depict broad high pressure dominating much of the west
Atlantic, and keeping a generally easterly flow over SoFlo. In the
mid-upper levels, model solutions agree in bringing a couple of weak
disturbances, which move over the area during the first half of the
work week, while mid-level high pressure gradually migrates into the
eastern Gulf region. Meanwhile, model soundings still depict a
persistently moist profile with PWATS at 2 inches or higher for most
of the long term days. This synoptic scenario will keep chances of
rain and storms on the high-end scattered to numerous range each
day, with highest chances during the afternoon hours.

The overall weather pattern will be similar to a typical summertime
one, with showers and thunderstorms developing near the east coast
metro areas late in the morning and early in the afternoon, then
moving to interior and west coast areas late in the afternoon as sea
breezes push inland. Main hazards with any thunderstorm that forms
will be heavy rainfall, and flooding.

For the end of the work week, uncertainty remains high as long-range
model solutions continue to present different scenarios for a
potential wave feature reaching the area. ECMWF is still the more
wet solution with very deep moisture and colder temps aloft across
the area, while GFS barely shows a much weaker disturbance in the
mid levels, along with a drier airmass. With little changes in
model performance, will keep capping POPs around 60 percent and
wait for better consistency in upcoming model runs. However, there
should be enough thermodynamic support and moisture for a few
cells to become strong, especially at the peak of daytime heating.

Temperatures remain hot with afternoon highs in the upper 80s to
lower 90s, and overnight lows in the mid to upper 70s. Heat indices
should hit the mi

&&

.AVIATION(18Z TAFS)...

Easterly flow remains (except for the diurnal Gulf sea breeze at
APF) through the period. Drier air may limit convective coverage
this afternoon and evening with the focus shifting to SW Florida.
Overnight, increasing easterly moisture will lead to increasing
convective activity to end the forecast period. Generally VFR with
some brief bouts of sub-MVFR possible. Short-fused AMDs may be
necessary for convection.

&&

.MARINE...

Persistent easterly winds this weekend as the influence of high
pressure builds in. Swell from Larry will diminish through the
weekend. A light onshore component to the wind is possible in the
mornings and afternoons along the nearshore Gulf waters.

&&

.BEACH FORECAST...

An elevated rip current risk continues for at least the Palm
Beaches, where swell from Larry is starting to diminish. The rip
current risk may increase along all the Atlantic beaches in the
coming days as the persistent easterly flow continues.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            80  90  79  90 /  30  50  50  60
West Kendall     79  90  78  91 /  30  50  50  60
Opa-Locka        79  90  78  90 /  20  50  50  60
Homestead        79  88  78  89 /  30  50  60  60
Fort Lauderdale  80  88  79  89 /  20  40  40  60
N Ft Lauderdale  80  89  79  89 /  20  40  40  60
Pembroke Pines   79  89  78  89 /  20  50  40  60
West Palm Beach  79  90  78  89 /  20  40  30  60
Boca Raton       80  89  79  89 /  20  40  40  60
Naples           77  92  77  92 /  30  60  30  60

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
GM...None.
&&

Tonight/Sunday and Aviation/Marine...RAG
Sunday Night through Saturday...AR

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Hazardous Weather Outlook for South Florida
National Weather Service Miami FL
351 AM EDT Sat Sep 11 2021

AMZ610-630-650-651-670-671-FLZ063-066>075-168-172>174-GMZ656-657-676-
120200-
Lake Okeechobee-Biscayne Bay-
Coastal waters from Jupiter Inlet to Deerfield Beach FL out 20 NM-
Coastal waters from Deerfield Beach to Ocean Reef FL out 20 NM-
Waters from Jupiter Inlet to Deerfield Beach FL from 20 to 60 NM-
Waters from Deerfield Beach to Ocean Reef FL from 20 to 60 NM
excluding the territorial waters of Bahamas-Glades-Hendry-
Inland Palm Beach-Metro Palm Beach-Coastal Collier-Inland Collier-
Inland Broward-Metro Broward-Inland Miami-Dade-Metro Miami-Dade-
Mainland Monroe-Coastal Palm Beach-Coastal Broward-Coastal Miami-
Dade-Far South Miami-Dade-
Coastal waters from Chokoloskee to Bonita Beach FL out 20 NM-
Coastal waters from East Cape Sable to Chokoloskee FL out 20 NM-
Waters from Chokoloskee to Bonita Beach FL from 20 to 60 NM-
351 AM EDT Sat Sep 11 2021

...Moderate Risk Of Rip Currents Beaches of Palm Beach County...
...Scattered Storms Interior/West Coast areas Today...
...Wet Pattern Rest of Weekend Into Next Week With Possible Heavy Rainfall...

This hazardous weather outlook is for South Florida.

.DAY ONE...TODAY AND TONIGHT

Rip Currents: There is a Moderate Risk of Rip Currents along the
beaches of Palm Beach County due to a small northeast swell.

Thunderstorms: Scattered showers and thunderstorms will be possible
over the interior and west coast metro areas this afternoon into
early this evening. The east coast metro areas will see isolated to
scattered showers and thunderstorms late tonight. Storms this
afternoon may produce gusty winds, cloud to ground lightning, and
heavy rainfall.

Wind: Thunderstorms this afternoon into early this evening will be
capable of producing brief gusty winds in excess of 40 mph over the
interior and west coast metro areas.

Waterspouts: Waterspouts are possible with any showers and storms
that form over the local waters today.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

Scattered to numerous showers and thunderstorms will be possible rest
of this weekend into next week with locally gusty winds, frequent
lightning, and heavy rainfall leading to possible localized flooding
over South Florida.

The enhance risk of rip currents will continue over the beaches of
Palm Beach County with rest of the east coast beaches increasing for
Sunday. The threat of rip currents will then decrease along the east
coast beaches of South Florida for next week.

.SPOTTER INFORMATION STATEMENT...

Widespread spotter activation is not anticipated, however,
individual spotters are encouraged to report high wind, hail and
flooding to the National Weather Service forecast office in Miami.

For more information...visit the National Weather Service in
Miami website at www.weather.gov/miami.

Baxter