Special Weather Statement, NWS Miami, FL

Area Forecast Discussion
National Weather Service Miami FL
255 PM EDT Mon Aug 23 2021

.SHORT TERM...

This Afternoon and Tuesday:

No meaningful changes in the large-scale pattern with troughing
located to our north, subtropical Atlantic ridging nosing in from
the east, and a series of Tropical Waves marching through the
Caribbean Sea. For South Florida a similar pattern will persist of
somewhat suppressed convection and hazy skies resulting from a
Saharan Air Layer (SAL). As with yesterday, the prevailing
southeasterly synoptic flow and expected Gulf/Lake Breezes will
favor the greatest afternoon shower/storm chances over the northern
Everglades and Lake Okeechobee regions. While the dry/dusty
conditions aloft should limit coverage a bit (especially by Tuesday)
the storms which do develop could be locally strong with gusty winds
possible. Otherwise warm temperatures and heat indices are the
continued story with apparent temperatures in the 100 to 105
degree range each afternoon.

.LONG TERM...

Tuesday Night through Monday:

With the Bermuda High remaining established across the region aloft,
lingering Saharan Dust associated with the current plume over our
area will continue to advect across the region through Wednesday
via prevailing and persistent easterly flow. With a relatively dry
airmass and low amount of precipitable water in the overall
vertical column, widespread shower and thunderstorm activity will
be inhibited. However it is important to note that although the
Saharan Dust can act as an inhibiting factor for the distribution
and areal coverage of shower and thunderstorm activity, some
shower and thunderstorm could still develop albeit relatively
isolated in nature. There is certainly the potential for a few of
these isolated thunderstorms to become locally strong to
marginally severe. The drier air in the mid-levels will allow for
steep lapse rates of 6.5 to 7.5 C/km, which when coupled with
differental heating and efficient insolation will allow for enough
buoyancy to sustain efficient convective updrafts. With the
relatively dry profile in the mid-levels as well as modest
forecast DCAPE values, there is the potential of a few isolated
strong wind gusts with the strongest thunderstorm activity
Wednesday afternoon. As mentioned in the previous AFD, the lack of
widespread shower and thunderstorm activity will allow for
maximum temperatures to remain slightly above average with the
warmest temperatures remaining across the interior areas of South
Florida. Prevailing easterly flow overnight will allow for minimum
temperatures along the east coast to remain warm, with slightly
cooler values elsewhere.

By Wednesday night into Thursday, a middle to upper level low will
propagate westwards into South Florida from the NW Bahamas. Model
guidance continues to depict the potential of an increase of
moisture in the lower to middle levels, as well as colder
temperatures aloft with a forecast 500mb temperature of -8C to -9C
during the day on Thursday. Even with an slight uptick in moisture,
there remains little confidence in the potential of widespread
shower and thunderstorm activity during this period at this time.
However this will be something to monitor as the week goes on, as
environmental conditions could support the potential for a few
stronger storms during the afternoon hours. Prevailing easterly
flow will act to focus shower and thunderstorm activity across the
interior and the Gulf coast.

By Friday, the middle to upper level low will exit the region as it
pushes northwestwards into the Gulf of Mexico. With the Bermuda High
once again building back into the region, prevailing easterly flow
will continue to remain as a constant across the region. The
greatest coverage of shower and thunderstorm activity will once
again be across the interior and Gulf coast region during the
afternoon hours as a typical summertime pattern sets up over the
region.

&&

.AVIATION(18Z TAFS)...

Shower/storm development this afternoon should remain inland from
the terminals. Although KAPF is a possible exception as the Gulf
Breeze pushes through around/after 18z. Otherwise SE winds 10-15
kt this afternoon decreasing to 5 kt or less tonight. Hazy skies
at times with the presence of a Saharan Air Layer aloft.

&&

.MARINE...

Generally quiet conditions are anticipated to start the week outside
of local effects from scattered showers and storms. Thereafter an
increase in winds, seas, and rain chances is expected by mid week.
Cautionary conditions are possible for mid to late week, so keep up
with forecast changes.

&&

.BEACHES...

Increasing onshore winds are expected for the Atlantic beaches with
an elevated rip current risk persisting through the week.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            81  92  80  92 /  10  20  10  40
West Kendall     79  93  79  93 /  10  20  10  40
Opa-Locka        80  93  79  91 /  10  20  10  40
Homestead        79  90  79  91 /  10  20  10  40
Fort Lauderdale  82  91  80  91 /  10  20  10  40
N Ft Lauderdale  81  91  80  91 /  10  20  10  40
Pembroke Pines   79  92  79  91 /  10  20  10  40
West Palm Beach  79  92  79  91 /  10  30  10  40
Boca Raton       81  91  79  91 /  10  20  10  40
Naples           78  93  77  93 /  30  30  10  40

&&

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

Tonight/Tuesday and Aviation/Beaches/Marine...SPM
Tuesday Night through Monday...Hadi

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Hazardous Weather Outlook for South Florida
National Weather Service Miami FL
709 AM EDT Mon Aug 23 2021

AMZ610-630-650-651-670-671-FLZ063-066>075-168-172>174-GMZ656-657-676-
232315-
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-
709 AM EDT Mon Aug 23 2021

...A Strong Storm or Two Possible Interior & Gulf Coast...
...Moderate Risk of Rip Currents East Coast Beaches...

This hazardous weather outlook is for South Florida.

.DAY ONE...TODAY AND TONIGHT

Thunderstorms: Isolated to scattered showers and thunderstorms are
possible, mainly over interior South Florida and the Gulf Coast
region this evening. The primary threat is lightning, gusty winds,
small hail, and brief heavy rainfall.

Hail: Small hail may be possible in the strongest storms this
afternoon across the Lake Okeechobee Region.

Wind: Strong to near severe wind gusts will be possible with the
strongest storms across the Gulf Coast and Lake Okeechobee Region.

Rip Currents: A moderate rip current risk exists for the east coast
Beaches.

Waterspouts: A few waterspouts are possible over the South Florida
coastal waters.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

Isolated to scattered thunderstorms, heat indices in the lower to mid
100s, and rip currents along the Atlantic coast are the main hazards
through the upcoming workweek.

.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.

Special Weather Statement
National Weather Service Miami FL
302 PM EDT Mon Aug 23 2021

FLZ069-070-231930-
Coastal Collier County FL-Inland Collier County FL-
302 PM EDT Mon Aug 23 2021

...A strong thunderstorm will impact portions of west central Collier
County through 330 PM EDT...

At 302 PM EDT, National Weather Service meteorologists were tracking
a strong thunderstorm capable of producing a funnel cloud over Golden
Gate Estates. This storm was nearly stationary.

HAZARD...Funnel clouds and winds in excess of 40 mph.

SOURCE...Radar indicated.

IMPACT...Funnel clouds occasionally touch down and produce tornadoes
         or waterspouts. Gusty winds could knock down tree limbs and
         blow around unsecured objects.

Locations impacted include...
Golden Gate Estates, Orangetree, West Toll Gate On Alligator Alley,
Golden Gate, South Blocks Golde, Picayune Strand State Forest and
Intersection I-75 And Everglades Blvd.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

These winds can down small tree limbs and branches, and blow around
unsecured small objects. Seek shelter in a safe building until the
storm passes.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

Persons participating in outdoor activities should seek sturdy
shelter until this storm passes. Open shelters found in parks,
beaches, or golf courses offer no protection from the dangers of
lightning.

&&

LAT...LON 2632 8152 2605 8145 2601 8165 2632 8172
TIME...MOT...LOC 1902Z 189DEG 2KT 2623 8159

FUNNEL CLOUD...POSSIBLE
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

Hadi/BNB