368
FXUS62 KMFL 160653
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
253 AM EDT Mon Sep 16 2024

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

.SHORT TERM...
(Today through Tuesday)
Issued at 250 AM EDT Mon Sep 16 2024

The persistent Rex Block synoptic pattern over the eastern United
States today will gradually begin to break down today as a
complex capture interaction of Potential Tropical Cyclone Eight
takes place in conjunction with an upper level low over the
southeastern United States. This interaction of the two lobes of
vorticity will weaken the existing mid-level ridge across the
northeastern United States and usher in a period of troughing
across a large swath of the eastern United States by late Monday.
This will usher in cooler temperatures aloft (-6C to -7C at 500mb)
and facilitate the development of stronger southwesterly 500mb
flow across the region. The CAMs (Convection Allowing Models) such
as the HRRR, RAP, etc depict a residual column of drier mid-level
air aloft today as well. At the surface, light and variable
surface winds will continue to prevail at the surface which may
facilitate the development of fairly patchy inland fog this
morning that should quickly burn off after sunrise. With the onset
of diurnal heating, the mesoscale-driven sea-breeze circulations
will gradually begin to develop during the late morning hours into
the early afternoon hours. Ample heating and initially clear
skies will result in another day of warm and toasty temperatures
across the region. Factor in the ample humidity courtesy of a
stalled frontal boundary just to the north of our area, and peak
heat index values will once again be in the triple digits before
convective initiation occurs. For this reason, a Heat Advisory has
been issued for Miami-Dade and Broward counties from 10am to 6pm
today as peak heat indices of 104-107 degrees fahrenheit are
forecast. With ample surface heat and cooler values aloft, lapse
rates will steepen today with the potential of mid-level lapse
rates of 6.0 to 6.5 C/km. The increased influence of synoptic
troughing will favor southwesterly background flow and the
continued evolution of convection developing over inland areas
before shifting towards the east coast metro.

Combining the mesoscale and synoptic factors listed above, there
is the potential for a few strong to marginally severe storms
across the east coast metro this afternoon. With background
southwesterly flow, the Atlantic sea-breeze will remain pinned
along the east coast metro which could provide localized ascent
and allow for the development of a few pulse storms reaching
strong to marginally severe levels. Residual dry air aloft may
result in wet microbursts with the collapse of the tallest cores
producing strong to marginally severe wind gusts. In addition,
given the veering of winds with height along the pinned Atlantic
sea-breeze, a brief tornado cannot be ruled out. The most
favorable region for a potential spin-up would be across coastal
Broward & Palm Beach counties as the Atlantic sea-breeze struggles
to make much inland progress. Aside from convective hazards, the
pinned Atlantic sea-breeze may also result in some limited scope
of a localized flooding hazard in localized pockets where heavy
rainfall falls. The latest HREF LPMM (localized probability-
matched mean) depicts the potential of a few localized pockets of
1-2 inches across the east coast metro areas which could result in
some localized flooding, especially if timed with the elevated
high tide cycles (King Tides). The combination of heavy rainfall
and higher than normal tides could result in slow drainage and a
lower threshold of localized flooding across coastal areas.

By Tuesday, the two lobes of 500mb vorticity across the southeastern
United States will merge into one concise area of low pressure.
This will keep southwesterly synoptic flow across the region and a
similar setup to what will be experienced across the region
today. 500mb temperatures will still remain in the ballpark of -6C
to -7C with mesoscale circulations and boundaries developing
during the afternoon hours. A threat of a few locally strong to
marginally severe storms across the east coast metro areas remains
possible on Tuesday afternoon as the Atlantic sea-breeze will be
pinned along the coast once again. Strong winds and the potential
of a brief spin-up along the Atlantic sea-breeze remains possible
on Tuesday afternoon. High temperatures will reach the lower 90s
each afternoon before convective initiation will result in a cool
down across affected areas.

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 250 AM EDT Mon Sep 16 2024

The mid-level low across the southeastern United States will
gradually lift northward through the mid-week period which will
veer 500mb flow across the region to a westerly then northwesterly
direction. The elongation of troughing over the eastern United
States will keep 500mb temperatures in the -6C to -7C range during
the mid-week period with forecasted daily afternoon lapse rates
in the 5.5 to 6.0 C/km range. At the surface, we will remain
situated to the south of the weak yet quite persistent stationary
boundary still draped across Central Florida. Ample precipitable
water (PWAT) values of 2.0+ inches and a fairly moist saturated
column will result in daily afternoon rain chances near
climatological norms. The prevailing weak surface winds and the
generally westerly flow aloft will keep a rain pattern favoring
SoFlos interior and eastern metro areas. Deeper convection will
again focus along sea breeze and outflow boundaries mainly in the
afternoon hours, with the continued potential of a few isolated
strong to marginally severe pulse storms when ascent is briefly
maximized along those aforementioned mesoscale boundaries.
Afternoon highs are expected to moderate a little and remain near
seasonal normals (upper 80s to low 90s). However, peak heat
indices will likely remain in the low triple digits, but should
remain just below heat advisory criteria.

&&

.AVIATION...
(06Z TAFS)
Issued at 131 AM EDT Mon Sep 16 2024

Mainly VFR conditions will prevail through the overnight hours
along with light winds. Some patchy fog may develop after 08z
across the interior and should stay away from the terminals. On
Monday morning, the east coast sea breeze will try to push inland
and it may shift winds to the SSE later in the afternoon mainly at
KPBI, KFLL, and KFXE. Scattered to numerous thunderstorms will
develop early this afternoon across the east coast terminals and
could bring periods of sub-VFR conditions during this time frame.

&&

.MARINE...
Issued at 250 AM EDT Mon Sep 16 2024

Generally light south to westerly winds will prevail through most
of this week as a weak surface boundary and Potential Tropical
Cyclone Eight remain north of the area. Seas across the northern
Atlantic waters will remain elevated through this afternoon as
northerly swell generated by Potential Tropical Cyclone Eight
offshore of the southeastern United States moves in. Scattered
showers and thunderstorms will be possible each day through the
period and could lead to locally higher winds and seas.

&&

.BEACHES...
Issued at 250 AM EDT Mon Sep 16 2024

Continued northerly swell from Potential Tropical Cyclone Eight
offshore of the southeastern United States will result in a high
risk of rip currents along the Palm Beaches today with a moderate
risk of rip currents being realized elsewhere along the east
coast. This ongoing northerly swell will result in a continued
elevated rip current risk through the middle part of the work week
along the east coast of South Florida as the swell gradually
subsides.

There will also be the continued potential for minor coastal flooding
around periods of high tide due to astronomically higher tides
associated with this full moon through mid-week. A Coastal Flood
Statement is in effect through at least Wednesday.

High Tide Times:

Naples: 12:05 pm Monday, 1:01 am Tuesday, 12:56 pm Tuesday
Lake Worth: 6:52 am Monday, 7:27 pm Monday, 7:46 am Tuesday
Port Everglades: 7:12 am Monday, 7:44 pm Monday, 8:06 am Tuesday
Virginia Key: 8:00 am Monday, 8:30 pm Monday, 8:53 am Tuesday

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            91  78  91  77 /  60  40  50  40
West Kendall     92  76  90  75 /  60  30  60  40
Opa-Locka        92  78  91  77 /  60  40  50  40
Homestead        91  78  90  76 /  60  40  50  40
Fort Lauderdale  90  78  91  77 /  50  40  50  40
N Ft Lauderdale  91  78  90  77 /  50  40  50  40
Pembroke Pines   94  78  91  77 /  60  40  50  40
West Palm Beach  93  77  90  76 /  40  30  50  40
Boca Raton       93  78  91  76 /  50  40  50  40
Naples           90  79  90  77 /  30  20  40  20

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory from 10 AM this morning to 6 PM EDT this evening
     for FLZ071>074-172>174.

     High Rip Current Risk through Tuesday evening for FLZ168.

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

$$

SHORT TERM...Hadi
LONG TERM....Hadi
AVIATION...CWC