919
FXUS62 KMFL 171217
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
817 AM EDT Sat Aug 17 2024

...New UPDATE...

.UPDATE...
Issued at 814 AM EDT Sat Aug 17 2024

No major changes to the near term forecast. Noticeable difference
in PWAT values across South FL this morning with 2.1-2.2 inches
across the Miami area closer to the surface boundary, and only 1.6
inches up in Palm Beach county. Highest PoPs today still appear to
be across the southern most portion of the peninsula, with chances
decreasing as you head north. High temps this afternoon will
generally be in the upper 80s to lower 90s.

&&

.SHORT TERM...
(Today through Sunday)
Issued at 229 AM EDT Sat Aug 17 2024

Strong ridging over the eastern half of CONUS will gradually
diminish through the weekend as a jet streak digs south over the
great plains and mid-Atlantic region. South Florida remains far
detached from these features, though a subtle veering of boundary
layer winds will materialize through the weekend from ENE to ESE.
This will maintain a sufficient moisture profile to support
scattered showers and thunderstorms through the period. The
greatest convective coverage will likely be realized over the
interior and southern portions of the region, including portions
of the east coast. The Weather Prediction Center has a marginal
risk for excessive rainfall over the southern and coastal portions
of South Florida today, and thus localized flooding will be a
threat to monitor with storms that develop.

Upper level trough will continue to deepen across eastern CONUS
Sunday, causing a further veering of winds out of the ESE to SE
across South Florida. This will allow for the greatest low-level
moisture flux convergence to be realized across the interior and
northern portion of the region (near Lake Okeechobee). With deep
tropical moisture in place (PW around 2.0 to 2.3 inches), expect
scattered to even numerous showers and thunderstorms across these
locations to round off the weekend. Localized flooding remains the
main concern, and cannot rule out a few stronger wind gusts where
highest values of SB CAPE and moisture flux convergence become
juxtaposed.

Max temperatures will remain in the upper 80s to low 90s across
the region this weekend with heat indices around 95 to 100.
Overnight lows will range from the upper 70s along the coast, to
the low 70s over the interior.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 229 AM EDT Sat Aug 17 2024

Extended-range models continue to depict a deep mid-to-upper-
level trough dominating much of the eastern CONUS as the work week
begins. Additionally, a frontal boundary is expected to stall
over northern Florida, enhancing moisture advection across South
Florida. As a result, precipitable water (PWAT) values will
increase to around 2 to 2.1 inches, which may prove to be a
conditionally favorable environment for the development of
scattered to numerous showers and thunderstorms, even in a weakly
forced regime. Localized flooding and isolated instances of flash
flooding cannot be ruled out through this period, particularly for
slow draining urban regions.

The Atlantic ridge will retreat from the central Florida
peninsula and the southwestern Atlantic, further establishing a
south- southwest flow regime across South Florida into the mid-
week period. Under this synoptic pattern, afternoon convection
will predominantly affect the interior northern and east coast
regions, particularly during the peak of diurnal heating. However,
morning showers are also possible due to the persistent southerly
flow, which will continue to transport moisture from the
Caribbean. Long-range models suggest the potential for several
shortwave perturbations to traverse the mid-to-upper levels of the
atmosphere, rotating around the base of a long-wave trough and
moving into the region. This could lead to a slight cooling of
500MB temperatures, increasing the threat of isolated severe
storms towards mid-to-late week.

Towards the end of the extended forecast, the Atlantic ridge is
expected to rebuild over the area, potentially accompanied by a
weak tropical wave that could bring additional moisture into South
Florida. However, we will await greater consistency among models
before making significant adjustments to the long-term
precipitation and weather grids. For now, expect climatological
PoPs, indicating scattered shower and thunderstorm coverage.

As the work week progresses, temperatures are anticipated to rise
following a short-lived weekend cooldown. Afternoon highs will
generally reach the mid-90s, with slightly lower temperatures
along the west coast in areas unaffected by showers and
thunderstorms. Heat index values will likely range from 100 to 105
degrees, with some locations reaching up to 108 degrees
Fahrenheit. The combination of daytime convection and increased
cloud cover should mitigate the persistence of oppressive heat,
though conditions will remain uncomfortably warm.

&&

.AVIATION...
(12Z TAFS)
Issued at 702 AM EDT Sat Aug 17 2024

SCT showers and thunderstorms today, especially this afternoon
into early evening may result in brief flight restrictions and
erratic winds. Outside of storms, E/NE winds around 5 kts this
morning increasing to 10-15 kts this afternoon.

&&

.MARINE...
Issued at 229 AM EDT Sat Aug 17 2024

Northeast winds will gradually become east this weekend, slowly
transitioning to southeast by the end of the weekend. Seas may
range from 2 to 4 feet, with higher values being realized over
northern waters (coastal/outer Palm Beach). Isolated to scattered
thunderstorms will be possible through the period. In and around
showers and thunderstorms, locally elevated seas and winds could
be realized.

&&

.BEACHES...
Issued at 229 AM EDT Sat Aug 17 2024

A persistent easterly wind flow over the weekend and into early
next week will bring an elevated risk of rip currents along the
Atlantic beaches of South Florida, particularly in the Palm
Beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            89  80  90  79 /  50  30  50  30
West Kendall     89  76  90  76 /  60  30  60  30
Opa-Locka        91  79  91  78 /  50  20  50  20
Homestead        88  77  88  77 /  60  30  60  30
Fort Lauderdale  89  79  89  79 /  40  20  40  20
N Ft Lauderdale  89  79  90  79 /  40  10  40  20
Pembroke Pines   92  79  93  79 /  40  20  40  20
West Palm Beach  90  78  92  77 /  20   0  20  10
Boca Raton       91  79  91  78 /  30  10  30  20
Naples           92  77  92  79 /  60  40  40  20

&&

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

$$

SHORT TERM...SRB
LONG TERM....SRB
AVIATION...CMF