044
FXUS62 KMFL 120633
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
233 AM EDT Wed Jun 12 2024

...New SHORT TERM, MARINE, BEACHES...

.SHORT TERM...
(Today through Thursday)
Issued at 147 AM EDT Wed Jun 12 2024

Somewhat drier mid-lvl air has filtered into SFL in the wake of
the earlier (convectively-enhanced) shortwave passage Tuesday
afternoon/evening. This combined with diurnal stabilization has
allowed for a general lull in heavier rainfall over the area early this
morning. This lull will likely not last very long as additional
convective development looks likely over portions of the area by
mid-morning (and potentially even by sunrise), as additional
shortwave impulses pivot into the area and interact with the
anomalous tropical moisture (PWATs 2.3-2.5 inches) that remains
pooled over South Florida.

The forecast for today remains complex, as the overnight guidance
suite hints at a plethora of plausible but sometimes conflicting
scenarios for how the day will evolve. There is a general
consensus that the best low-lvl convergence and moisture pooling
will be over northern areas of our CWA in the Lake region, and
many of the global models place their QPF maximum in this vicinity
(or even north of our area altogether). However, many of the
higher-res guidance hint at greater convective coverage/intensity
south of this zone of broader ascent likely fueled by greater
diurnal destabilization and potentially a weak differential
heating boundary. Both the northern and southern foci seem
plausible so went with a broadbrushed approach for QPF, giving
slightly more weight to the southern solution as it is favored by
the CAMs and we are only 6-18 hours out.

Whether the northern or southern solution pans out will have
impacts on today`s hydrology concerns, as the northern third or
so of the area saw significantly less rainfall (generally 2 inches
or less) on Tuesday compared to the region between Tamiami Trail
and Alligator Alley which observed a widespread 3-6 inches, with
localized amounts of up to 8 inches. This observed rainfall
gradient is evident in FFG with 6 hour FFG varying from around 2
inches in coastal Collier and Miami-Dade to 4-5 inches in Palm
Beach/Glades/Hendry counties. Consequently a southern solution
would likely result in greater hydrologic impacts, as several
inches of rain would be likely over already saturated areas, while
the northern solution would be more "equitable" and ideally less
impactful (unless it focused over urban portions of PB county).

The only notable change to the synoptic pattern on Thursday will
be the development of an intensifying sfc. low over the stalled
boundary to our north, just off the SE Coast. This low (which may
eventually acquire subtropical characteristics over the Gulf
Stream) will shift NE in the late week period, but looks to at
least in the short term keep the subtropical moisture tap in place
over our area through Thursday (i.e. the classic cyclone moisture
tail). With the potential for significant additional rainfall
(HREF PMMs would indicate areas of 2-4 inch totals possible) and
likely saturated ground made the decision to extend the Flood
Watch through Thursday evening with this morning update.

&&

.LONG TERM...
(Wednesday night through next Monday)
Issued at 256 PM EDT Tue Jun 11 2024

An active subtropical jetstream will become entrenched over central
Florida, just downstream of a positively tilted major short-wave
trough that will impart on the Gulf of Mexico. This will allow for a
fetch of deep tropical moisture to remain entrenched over South
Florida, thus resulting in a prolonged period of widespread rainfall
will continue through the remainder of the week. Hydrologic concerns
will be the primary focus through the remainder of the week,
primarily owing to antecedent rainfall from previous days, and the
repeated bouts of strong thunderstorms capable of producing very
high tropical rainfall rates. With precipitable water remaining
above 2.0 inches, expect favorable conditions for flooding and even
flashing flooding - particularly for urban locations. The most
intense rainfall will develop in tandem with upper level impulses
that trek through the CWA through this period. As far as rainfall
totals through Friday, expect 4-8 inches for the western half of the
region, and 2-6 inches for the eastern half of CWA (including
metropolitan east coast), with locally higher totals possible. These
totals are subject to deviate based on how the forecast evolves in
the coming days.

A stationary frontal boundary will gradually dissolve, as low-level
circulations develop over the southern Gulf of Mexico and coastal
FL/GA respectively. This will likely stretch/divert moisture away in
opposite directions away from the region, though there will still be
lingering deep tropical moisture such that heavy rainfall will still
be a concern through the weekend. By late Saturday/early Sunday, a
backing of low-level winds will be realized as expansive Bermuda
ridge of high pressure expands southwestward. An easterly flow
regime will likely become re-established, which will allow for
periods of heavy rainfall in the morning along the east coast, with
more coverage generally along interior and western portions of the
CWA. Heavy rainfall and flooding will be the primary concerns again,
though the threat should be diminished in comparison to earlier in
the week. Nevertheless, cannot rule out the potential for flooding
through the weekend, mostly conditional on measured rainfall up to
this point.

High temperatures will begin to increase slightly through the period
with mid 80s expected on Friday and slightly increasing each
afternoon. Highs will reach the lower 90s again by the Tuesday-
Wednesday time frame.

&&

.AVIATION...
(06Z TAFS)
Issued at 115 AM EDT Wed Jun 12 2024

A general lull in rainfall over the area will continue for the
next few hours, however, numerous shower and thunderstorm
development looks likely during the daytime hours. Periods of
IFR (or even briefly lower) conditions look likely in heavy
rainfall. Outside of storm outflows generally southerly winds will
prevail through the daytime hours.

&&

.MARINE...
Issued at 147 AM EDT Wed Jun 12 2024

Near hazardous southerly winds will persist over the area waters
today, as the area remains south of a stalled front and associated
surface low. These winds will decrease Thursday into the late
week period as the low progresses northeast into the Atlantic
waters. Numerous showers and thunderstorms remain likely through
much of the upcoming week resulting in periods of locally higher
winds and seas. Outside of storms wave heights should remain 3 ft
or less through the forecast period.

&&

.BEACHES...
Issued at 147 AM EDT Wed Jun 12 2024

The moderate risk of rip currents will continue today for the
beaches of Collier county as breezy SW flow persists.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            86  77  84  76 /  90  90  90  90
West Kendall     87  75  86  75 /  80  80  90  90
Opa-Locka        87  77  86  76 /  90  90  90  90
Homestead        87  77  86  76 /  80  90  90  90
Fort Lauderdale  85  76  83  77 /  90  90  90  90
N Ft Lauderdale  86  75  84  76 /  90  90  90  90
Pembroke Pines   88  77  86  77 /  90  90  90  90
West Palm Beach  86  75  84  75 /  90  80  90  80
Boca Raton       87  75  85  76 /  90  80  90  90
Naples           87  77  86  77 /  90  80  90  90

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Flood Watch through Thursday evening for FLZ063-066>075-168-
     172>174.

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

$$

SHORT TERM...Carr
LONG TERM....SRB/Rizzuto
AVIATION...Carr