C Gables, Florida Weather Forecast Discussion

870
FXUS62 KMFL 151846
AFDMFL
Area Forecast Discussion
National Weather Service Miami FL
246 PM EDT Mon Sep 15 2025
...New UPDATE...
.UPDATE...
Issued at 242 PM EDT Mon Sep 15 2025
A slightly drier air mass remains in place across South Florida,
evident in the lack of showers and storms currently on radar. For
now, pleasant conditions prevail with mainly sunny skies across
the majority of the area. A few showers and storms should begin to
develop over the next 1 to 2 hours and linger into the early
evening hours. These showers and storms will likely develop across
the western suburbs of the east coast metro areas and eastern
Everglades and push towards the coastline during the early
evening. Once daytime heating is lost after sunset, this activity
should dissipate rather quickly making way for a mainly dry
overnight period.
&&
.SHORT TERM...
(Today through Tuesday)
Issued at 123 AM EDT Mon Sep 15 2025
A drier airmass remains in place across South Florida today as a
plume of drier mid-level air still resides over our area, on the far
southern periphery of influence with a stationary cut-off low. 05z
RTMA and ACARS data from KMIA/KFLL/KPBI indicate a substantial
amount of dry air from 850mb up in the vertical column which present
an interesting forecast conundrum. While overall rain chances are
still expected to be in the 30-50% range today, analysis of various
forecast model soundings from convection allowing models (CAMs)
suggest the potential of an isolated strong to severe wind gust
threat with the most robust afternoon and early evening storms. In
such a classic high CAPE, weak shear environment, multicellular
thunderstorm clusters will propagate along outflow boundaries,
bringing the threat of gusty winds and excessive lightning as they
pulse up and down in intensity. DCAPE (Downdraft Convective
Available Potential Energy) values of 1000+ J/kg, steep low level
lapse rates of 7 to 9 C/km, and unstable surface CAPE of
3000-4000+ J/Kg will support the threat of one or two strong to
marginally severe storms. Technical factoids above out of the way,
in simple terms, the drier air aloft may result in some strong to
marginally severe downbursts. As these downbursts hit the
surface, momentum forces the air to push outwards in all
directions, resulting in the potential of strong to marginally
wind gusts at the surface as a storm collapses. Light northerly
winds during the morning hours will veer onshore along both coasts
by the early afternoon hours resulting in the greatest
convergence of storms across inland areas today.
South Florida will still remain on the north side of the stalled
frontal boundary over the the Florida Straits. Forecasted
precipitable water values today will begin the slow gradual climb
upwards as values increase to the 1.6 to 1.8 range during the
afternoon hours. As our rain chances remain below climatological
norms, the cooling benefits that we have seen from the previous
pattern of widespread shower and storm coverage will be limited in
spatial and temporal extent. This will result in the continued trend
of higher afternoon temperatures today with forecasted highs in the
upper 80s to low 90s area-wide.
Effectively blocked by mid-level ridging to the east over the
western Atlantic waters, the aforementioned cut-off low will remain
in place over the southeastern United States coast on Tuesday as the
weak surface low moves onshore across coastal North Carolina. This
surface low remains attached to the persistent frontal boundary that
we dealt with last week, now elongated from the western Atlantic
waters into the Florida Straits. Although we still remain to the
north of the boundary, atmospheric moisture will continue to trend
up with forecasted precipitable water values back in the 1.9 to 2.1
range, especially across the southern half of South Florida. At the
same time, forecast model soundings depict the gradual mixing out of
drier air aloft, resulting in a more saturated vertical profile on
Tuesday. However there will still be enough mid-level dry air to
support the potential of an isolated strong to severe wind threat
with the most robust afternoon and early evening storms once again
on Tuesday. Chances of precipitation increase to the 50-70% range
during the afternoon and evening hours, with the greatest coverage
expected across inland areas but convective action may spread to the
entirety of South Florida via sprawling outflow boundaries. High
temperatures will once again reach the upper 80s to low 90s with
sharp temperature fluctuations possible in and around shower and
thunderstorm activity.
&&
.LONG TERM...
(Tuesday night through Sunday)
Issued at 123 AM EDT Mon Sep 15 2025
By mid-week, the aforementioned cut-off low will begin a slow
acceleration to the northeast out ahead of the next longwave trough
pushing eastward across the central United States. The attached
frontal boundary over the Florida Straits will be pulled back
northwards (pseudo warm front?) as the "parent" surface low lifts
north. As the front arrives back over South Florida, even deeper
moisture is forecast to make a return to the region with the
continuance of an increasing trend in precipitable water values.
Maximum daily rain chances increase to the 60-80% range Wednesday
through Friday. By Wednesday, forecast model guidance once again
depicts the potential of a saturated atmosphere over South Florida
with precipitable water values in the 2.1 to 2.3 inch range (once
again over the the percentile). These forecast model soundings once
again depict a classic skinny CAPE profile that points to the
potential of efficient rainfall rates that could lead to localized
flooding concerns. ECENS and GEFS ensemble guidance suites depict a
higher QPF signal across the entire region which coincides with the
return and stall of the frontal boundary. WPC cluster analysis also
highlights a heavy rainfall threat across the region during this
time frame.
With the background environment conducive for heavy rainfall, the
main driving force behind rainfall accumulations will be the
coverage and storm motion of afternoon showers and storms across the
region during the second half of the week. Similar to last week,
sharp rainfall gradients may materialize with problematic pockets of
higher rainfall totals resulting in the potential of urban flooding.
As of the writing of this discussion, The Weather Prediction Center
(WPC) has placed the southeastern portion of South Florida in a
Marginal Risk (level 1 of 4) of excessive flooding on Wednesday with
the threat increasing in spatial extent to the entire east coast on
Thursday. With the abundance of convective activity and resultant
cloud debris, high temperatures may be held in check during this
period with forecast highs in the mid to upper 80s each afternoon.
Forecast guidance keeps the stalled frontal boundary in place over
South Florida into the upcoming weekend which will result in
scattered to numerous showers and storms each afternoon and evening.
While mid-level troughing will weaken over the eastern United States
during this time period, 500mb flow will remain out of a
southwesterly direction continuing to advect deeper mid-level
moisture into South Florida. The lessening of mid-level flow aloft
will once again result in sea-breeze circulations remaining the main
foci of diurnal convection each afternoon and evening.
&&
.AVIATION...
(18Z TAFS)
Issued at 1237 PM EDT Mon Sep 15 2025
Scattered showers and storms expected to develop between 18Z-19Z
and may bring sub-MVFR cigs and visibilities along with erratic
wind shifts. Winds become light and variable again overnight with
another chance for showers and storms Tuesday beginning late
morning into the early afternoon.
&&
.MARINE...
Issued at 123 AM EDT Mon Sep 15 2025
A gentle to moderate northerly breeze will continue across most of
the local waters into early next week before veering out of a
northeasterly direction and enhancing by the mid week period. Seas
across the Atlantic waters will generally remain between 2 to 4 feet
through mid next week while seas across the Gulf waters remain at 1
to 2 feet. Periods of rough seas and gusty winds will be possible
each day near the most robust shower and thunderstorm activity.
&&
.BEACHES...
Issued at 123 AM EDT Mon Sep 15 2025
A high risk of rip currents will develop across the Palm Beaches
today as onshore flow develops this afternoon and a northeasterly
swell in the Atlantic waters lingers. This rip current risk will
increase and expand further south across the east coast by Tuesday
as easterly winds increase in strength.
&&
.PRELIMINARY POINT TEMPS/POPS...
Miami            77  89  76  86 /  30  60  40  70
West Kendall     75  90  76  86 /  30  60  40  70
Opa-Locka        77  90  77  87 /  30  60  40  70
Homestead        76  88  76  86 /  30  50  50  70
Fort Lauderdale  77  88  77  86 /  30  60  40  70
N Ft Lauderdale  77  89  78  87 /  30  50  40  70
Pembroke Pines   77  91  78  89 /  30  60  40  70
West Palm Beach  77  89  77  87 /  30  50  40  60
Boca Raton       77  90  76  87 /  30  50  40  70
Naples           75  91  76  87 /  10  50  30  70
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk until 8 PM EDT this evening for FLZ168.
AM...None.
GM...None.
&&
$$
SHORT TERM...Hadi
LONG TERM....Hadi
AVIATION...Rizzuto

NWS MFL Office Area Forecast Discussion