491
FXUS62 KMFL 210519
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
119 AM EDT Fri Aug 21 2026

...New SHORT TERM, LONG TERM, AVIATION, MARINE...

.KEY MESSAGES...
Updated at 116 AM EDT Fri Aug 21 2026

 - Heat index values peak between 105-110 degrees today with a
   Heat Advisory in effect only for Miami-Dade and Broward
   counties.

 - Scattered thunderstorms expected after midday and into the
   evening. A couple of stronger storms are possible that could
   produce near-severe winds.

&&

.SHORT TERM...
(Today through Saturday)
Issued at 116 AM EDT Fri Aug 21 2026

As the ridge in the Southwestern US continues to strengthen,
increased jet dynamics will result in an amplified trough across
most of the Eastern Seaboard through this weekend. The base of the
trough is not anticipated to make it all the way to South Florida
and the overall flow pattern will remain largely on the weaker side,
but this enhanced troughing pattern is expected to keep a prevailing
southerly/south-southwesterly flow pattern in place today and
Saturday. Therefore, with abundant moisture advection continuing and
elevated PWATs of 1.7-2.0" or even more in some areas, diurnal
heating and sea breeze circulations each day will have the necessary
ingredients to produce scattered to numerous showers and
thunderstorms. With the primary south to south-southwest flow, this
will favor interior and Southeast Florida for highest rain chances
both today and on Saturday as showers and storms are expected to be
the most widespread in these areas. Some activity will be observed
across Southwest Florida as well, just not as widespread and thus
rain chances are between 30-50% there versus 50-70% across Southeast
Florida. Model soundings do highlight adequate SBCAPE of 3000-4000
J/kg as well as inverted-V signatures and steep low level lapse
rates, so there will be an outside chance for an isolated severe
storm or two via gusty winds. Otherwise, the primary hazards will be
heavy rainfall that could lead to localized flooding in poor
drainage areas, and sub-severe strong wind gusts.

High temperatures the next couple days will remain in the low to mid
90s. The deeper moisture will also keep dew points in the mid to
upper 70s each day, thus maximum heat index values are anticipated
to remain elevated up to the 105-110F range. Isolated locations
could experience heat index values a couple of degrees higher for a
short period of time. With the expectation of some increased cloud
cover today and perhaps slightly lower dew points, it has been
decided to only issue a Heat Advisory for Miami-Dade and Broward
counties from 11AM - 6PM today. HREF probabilities currently
indicate a 10% or less chance for heat indices to reach 108F or
higher. Depending on how conditions are trending through the
morning, a short-fused expansion of the advisory will be possible
but is not imminent.

&&

.LONG TERM...
(Saturday night through Thursday)
Issued at 116 AM EDT Fri Aug 21 2026

As the trough draped across the Eastern Seaboard starts to erode
early next week, the local wind regime will start to shift back to
what we typically see in the summer time here in South Florida with
low level flow being dominated by the Atlantic sea breeze. This will
cause diurnal convection to start focusing back over both the
interior and Southwest Florida rather than Southeast Florida like
has been observed recently. Starting Monday, the highest rain
chances (60-80%) will begin to focus across Southwest Florida and
this will last through the end of the long term period.

Latest guidance shows some slightly drier air (PWATs falling back
below 1.8-2.0") this weekend, which could result in some slightly
lower dew points that end the current streak of consecutive days
with Heat Advisories. There is also potential for another Saharan
Air Layer (SAL) to impact the area late in the weekend and early
next week, but guidance highlights this SAL breaking up upon it`s
arrival and thus it`s influence on a return to hot conditions
should be less than the previous round.

High temperatures are projected to remain in the low to mid 90s each
day with overnight lows ranging from the low 70s across the interior
and lake regions to the upper 70s and low 80s along the coastal
metros.

&&

.AVIATION...
(06Z TAFS)
Issued at 116 AM EDT Fri Aug 21 2026

Mainly VFR conditions will prevail through the forecast period.
Light winds at east coast terminals overnight will increase out of
the east after 16Z. Scattered afternoon showers and thunderstorms
may require short-fused AMDs and TEMPOs for east coast terminals
after 20Z. At KAPF, light winds tonight will increase out of the
west after 16Z.

&&

.MARINE...
Issued at 116 AM EDT Fri Aug 21 2026

Gentle west-southwest winds are expected across the Gulf waters
today with southerly winds continuing across the Atlantic. The
Atlantic winds will eventually become more southeasterly over the
weekend. Seas will remain at 1-2 feet or less each day across all
local waters. Scattered showers and thunderstorms are possible late
each day and in the late night hours which may result in locally
hazardous winds and seas.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            93  79  93  79 /  50  20  50  10
West Kendall     92  77  92  76 /  40  10  50  10
Opa-Locka        93  80  93  79 /  50  20  50  10
Homestead        92  78  92  78 /  30  10  40  10
Fort Lauderdale  92  80  92  79 /  50  20  50  10
N Ft Lauderdale  93  80  93  79 /  50  20  50  20
Pembroke Pines   93  80  93  79 /  50  20  50  10
West Palm Beach  94  78  93  77 /  50  20  50  10
Boca Raton       92  79  92  79 /  50  20  50  20
Naples           91  79  91  78 /  30  20  20  10

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory from 11 AM this morning to 6 PM EDT this evening
     for FLZ071>074-172>174.

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

$$

SHORT TERM...Redman
LONG TERM....Redman
AVIATION...Redman