702
FXUS62 KMFL 122334
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
734 PM EDT Mon Aug 12 2024

...New UPDATE, AVIATION...

.UPDATE...
Issued at 722 PM EDT Mon Aug 12 2024

Latest 00Z MFL sounding indicates a pocket of drier air aloft in
the mid-levels, which is further reinforced by satellite PWI
(precipitable water index) sampling around 1.5-1.7 inches. While
still sufficient to produce isolated to scattered thunderstorms,
this is a departure from the norm in this typically wet period of
August. Expect this drying trend to continue through tomorrow,
where PoPs are anomalously low (around 20-40 area-wide on
average). Storms that do develop will generally be of the garden
variety and mostly short-lived.

&&

.SHORT TERM...
(Rest of today through Tuesday)
Issued at 1258 PM EDT Mon Aug 12 2024

Another day of very warm and humid conditions across South
Florida as the Bermuda High persists over the area. A shallow
pocket of Saharan dust is gradually pushing over the area from
the southeast, and will knock PWAT values down to more seasonable
averages (1.7-1.9 inches) later on this afternoon and evening.
Despite this, there will still be enough low to mid level
moisture to support shower and thunderstorm development along the
sea breeze convergence boundaries, beginning along the westernmost
edges of the East Coast metro area in the early afternoon hours,
and progressing northwest towards the Lake region and the
interior through late afternoon and evening.

The setup remains pretty similar on Tuesday as the high
continues to expand over the region and the shallow
Saharan dust plume lingers over the area. Plenty of low-level
moisture will still be in place across the region, supporting
isolated morning showers along the east coast, with isolated to
scattered shower and thunderstorm activity over the interior and
Lake Okeechobee areas during the afternoon.

With limited cloud coverage expected, temperatures will rise to
the low to mid 90s across much of the region both this afternoon
and Tuesday afternoon. The warm temperatures combined with muggy
dewpoints will once again result in heat indices reaching the
105-110 degree range for much of the area. A Heat Advisory is in
effect for all of South Florida through 6 PM today, and may be
needed again on Tuesday.

&&

.LONG TERM...
(Tuesday night through next Sunday)
Issued at 218 PM EDT Mon Aug 12 2024

The main story of the long-term will be the weakening of the
subtropical ridge and the establishment of east coast troughing
and ridging over the SW/South-Central CONUS. This process will
begin on Wednesday with PWATs increasing to near climo after the
early week dust outbreak, and low-lvl flow being light and sea
breeze driven. PoPs should increase to the 40-60% range (highest
over the Interior) with the light flow and warm airmass
supporting highs in the mid 90s and heat indices above advisory
thresholds area-wide. Heading into Thursday a weak frontal
boundary will begin to move into northern Florida favoring
northwesterly low-lvl flow over the area. This will create an
enhanced zone of low-lvl convergence and moisture pooling over
the area (especially over the southern half of SFL), which will
maintain PoPs in the likely range (although heat headlines look
likely before precipitation develops).

Forecast uncertainty increases a for the Friday-weekend period as
some members of guidance (notably the Euro/ICON) actually have
the audacity to tease us with a frontal passage in mid August,
while others (the GFS/CMC) favor a more climo solution which shows
the postfrontal wind-shift making it through our area and some
slight mid- lvl drying but no low-lvl Theta E response. Although
the eastern trough will certainly amplify over the weekend (and
thankfully steer future Ernesto well clear of the area), I still
have skepticism of a clean sfc.frontal passage this time of year
so kept temps near climo for the weekend with reduced PoPs, as at
least some mid-lvl drying looks likely.

&&

.AVIATION...
(00Z TAFS)
Issued at 722 PM EDT Mon Aug 12 2024

Generally VFR conditions are expected to prevail through the TAF
cycle. Any lingering SHRA/TSRA will likely wane by 01-02Z. Winds
generally light/vrb, then BCMG ESE around 5-10 kt on Tuesday by
mid-morning. Less overall convection expected due to influx of
drier air, though ISLD/SCT storms may still spawn over interior
and SW portions of the region. Gulf sea breeze is likely to
materialize over/near APF.

&&

.MARINE...
Issued at 1258 PM EDT Mon Aug 12 2024

Gentle easterly-southeasterly winds will prevail over the local
waters through the first half of the week, although afternoon wind
shifts to the W-SW will be possible over the nearshore Gulf
waters. Seas should remain 2 ft or less through at least mid week.
Although the pattern will favor the highest thunderstorm chances
over land, isolated-scattered storms will be possible over the
waters each day. In and around showers and thunderstorms, locally
elevated seas and winds could be realized.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            81  93  81  94 /  10  30  10  40
West Kendall     78  94  79  94 /  10  40  10  40
Opa-Locka        81  95  81  94 /  10  30  10  40
Homestead        80  93  80  93 /  10  40  10  40
Fort Lauderdale  81  91  81  92 /  10  20  10  30
N Ft Lauderdale  81  93  81  93 /  10  20  10  30
Pembroke Pines   81  96  82  97 /  10  30  10  40
West Palm Beach  80  93  80  94 /  10  20  10  30
Boca Raton       80  93  80  94 /  10  20  10  30
Naples           78  93  79  92 /  20  40  20  40

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory from 10 AM Tuesday to 6 PM EDT Wednesday for
     FLZ063-066>075-168-172>174.

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

$$

SHORT TERM...Culver
LONG TERM....Carr
AVIATION...SRB