Areal Flood Advisory 202, NWS Miami, FL

Area Forecast Discussion
National Weather Service Miami FL
249 PM EDT Fri Sep 24 2021

...One More Day of Wet Wetter Before Drier Conditions Late This
Weekend Into Early Next Week...

...Increase Risk Of Rip Currents East Coast Beaches Of South
Florida this Weekend Into Next Week...

.SHORT TERM...

Through Saturday:

A weak quasi-stationary frontal boundary lounging across the Lake Okeechobee
Region will keep a tight moisture gradient across South FL. Just to show this
gradient, MFL’s 24/12Z sounding measured a PW of 2.04 inches whereas TBW and
JAX measured 1.53 inches and 0.83 inches, respectively. I don’t know about
you but I much rather see the lower humidities and drier weather that the
northern portions of the state get to experience. To put these excessive PW’s
into perspective, the moving average for MFL is 1.70 inches. With that said,
based off this morning’s sounding, South FL is running close to the 90th
percentile in respect to the climatological normal. Another day with very
weak steering flow, though has a subtle west component. Thus, scattered to
numerous showers and thunderstorms are forecast across South FL today,
especially during the afternoon hours. Highest chances will shift from west
to east, with the Gulf Coast seeing late morning/early afternoon activity
and the east coast seeing early afternoon/early evening activity. Due to
the aforesaid weak steering flow, slow storm motion is expected along with
the increased potential for locally heavy rainfall and flooding. Aside
from hydro concerns, lightning and gusty winds are possible with the
stronger storms this afternoon. Convection should diminish overnight with
activity generally flaring up over the warm Gulf Stream waters in the
Atlantic.

Not much change in the forecast going into Saturday. A copy and paste of
Friday’s forecast can be inserted for Saturday. One small difference is
that the low-level flow will transition to more of a northeasterly flow,
except for the Gulf Coast where southwesterly winds will develop once the
Gulf Breeze pushes inland by the afternoon hours. Weak steering flow with
a subtle westerly component once again Saturday, favoring the east coast
for scattered to numerous showers and thunderstorms during the afternoon
through early evening hours. Models suggest a pre-frontal trough dragging
across northern areas of the CWA Saturday, more so across Palm Beach County
and the Lake Region. The areas closest to the trough may see slightly more
enhanced convection due to increased instability. Main hazards once again
related to hydro, though with drier air nosing its way into northern areas
of the CWA, an isolated damaging wind gust cannot entirely be ruled out.

Temperatures near average for this time of year, with highs in the mid to
upper 80s. Heat indices in the mid to upper 90s areawide.

.LONG TERM...

Late This Weekend...
A stationary front over the Lake Okeechobee region on Saturday
will move southward through South Florida on Sunday, as the mid to
upper level trough moves eastward from the Tennesee valley into
the Mid Atlantic States. This will allow for the steering flow to
become more northerly over South florida allowing for drier air to
work into the region. Therefore, POPs on Sunday will be in the
slight chance over the northern areas with low end chance POPs
over the southern areas. The threat of storms will mainly be over
the southern areas on Sunday ahead of the front.

Early Next Week...
The weather pattern across the United States will become a blocky
pattern with a over the Western United States and the Eastern
United States with the mid to upper ridge over the Central United
States. There will also be a surface high over Northern Florida
during this time frame. This will allow for the surface winds to
be from the northeast direction with speeds becoming moderate to
breezy at times. The mid to upper levels will also remain dry during
this time. Therefore, most of South Florida will remain dry except
for the eastern areas where isolated showers will be moving into
the area from the Atlantic waters.

Middle to End of Next Week...
The long range models are showing an mid to upper level low
breaking off from the mid to upper level trough over the eastern
United States and regorating back into the Southeastern United
States. This will allow for deeper moisture to work back into
South Florida during this time and bring back scattered showers
and even a few thunderstorms.

The long range models are showing Hurricane Sam turning toward the
Northern Atlantic waters and keeping the system away from South
Florida at this time. Please continue to monitor the the latest
information from the Hurricane Center on Hurricane Sam through
this weekend into next week.

&&

.AVIATION(18Z TAFS)...

Northeast winds are anticipated for most areas this afternoon with
the exception of along the Gulf coast where a sea breeze will turn
winds westerly around 19Z. Scattered to numerous showers and
thunderstorms expected through the early evening hours. Temporary
lower ceilings and visibilities are possible should a storm impact
any particular airfield. Quiet tonight with light and variable
winds, with similar weather returning for tomorrow.

&&

.MARINE...

Surface winds will begin to shift to a more northeasterly direction
as high pressure sets up over the mid-south states this weekend. A
light to moderate northeasterly fetch and building (northeasterly)
long period swell can be expected. That said, conditions should
remain at or below cautionary headline thresholds. Additionally,
locally higher winds and seas are possible near convection through
the weekend.

&&

.BEACHES...

A building long period swell across the Atlantic waters will allow
for an elevated risk of rip currents into the upcoming weekend,
especially along the Palm Beaches. Moderate northeasterly winds
this weekend into next week will also elevated risk for rip
currents for rest of the east coast beaches of South Florida.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            76  89  75  89 /  40  60  30  50
West Kendall     74  90  74  90 /  40  60  30  50
Opa-Locka        75  89  75  89 /  40  60  30  50
Homestead        74  89  74  88 /  40  60  30  50
Fort Lauderdale  76  88  76  88 /  50  60  30  40
N Ft Lauderdale  77  88  76  88 /  50  60  30  40
Pembroke Pines   75  88  75  88 /  40  60  30  40
West Palm Beach  75  88  75  88 /  40  60  20  30
Boca Raton       76  87  75  87 /  40  60  30  40
Naples           75  89  74  89 /  40  50  20  30

&&

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

Tonight/Saturday...Fell
Aviation/Beaches/Marine...SPM
Saturday Night through Friday...BNB

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