Area Forecast Discussion
Issued by NWS Miami, FL

Home |  Current Version |  Previous Version |  Graphics & Text |  Print | Product List |  Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48
075
FXUS62 KMFL 181814
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
214 PM EDT Wed Sep 18 2024

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

.SHORT TERM...
(Rest of today through Thursday)
Issued at 210 PM EDT Wed Sep 18 2024

A trough of low pressure over the southeastern United States is
keeping an unsettled pattern over much of Florida today and
Thursday. With the trough axis generally east of southern Florida,
some relatively cooler air has moved in aloft allowing for
somewhat steeper lapse rates compared to previous days.
Precipitable water values have dipped below 2 inches but there is
still plenty of atmospheric moisture around to allow any slow-
moving storms that may form today to be efficient rainfall
producers. There is also the potential for some strong to locally
damaging wind gusts with the more vigorous convection that may
develop today.

The westerly component to the wind flow is just present enough to
pin the Atlantic sea breeze near the coast offering a focus for
convection this afternoon and again on Thursday. Repeated rainfall
could lead to localized saturation which will need to be
monitored as moisture recovery in the coming days could build into
an increasing risk of urban flooding from excessive rainfall.
Temperatures will reach the lower 90s again on Thursday afternoon
and heat index values should reach the 100 to 106 range.

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 210 PM EDT Wed Sep 18 2024

By the end of the work week and into the upcoming weekend, upper
level troughing will continue to dig southward into the eastern
Gulf of Mexico and over South Florida, maintaining west-north
westerly flow over the region aloft. Meanwhile a persistent plume
of deep tropical moisture remains in place over the region as a
diffuse stationary frontal boundary meanders through this period.
The presence of cooler upper level temperatures (-6 to -7C @ 500
mb) and a pocket of divergence aloft may act to enhance convective
coverage and intensity at times, though most convective will be
driven by localized convergence maxima owing to mesoscale
processes (sea- breeze and outflow boundary collisions). Expect
bouts of periodic heavy rainfall to continue, particularly in the
afternoon when instability and low-level convergence is maximized.
Heavy rainfall that persists for a prolonged duration over urban
areas may result in the usual localized flooding concerns.

By Sunday and into early next week, a dominant/expansive ridge of
high pressure will emanate from the TX/Mexico region and increase
geopotential heights across South Florida. This may be
commensurate with a wedge of drier air advecting towards the
region through this same period (simultaneously), though there
exists uncertainty regarding the southward extent of this drier
air-mass. For now, it appears that strong upper ridging coupled
with a lack of moisture should allow for rainfall totals that are
below climatological norms through this period.

Temperatures through this period will hover around seasonal norms
through this period. Afternoon high temperatures should reach the
upper 80s to low 90, while dew points reach the mid to upper 70s
through the early part of the weekend. Heat Advisories may be
necessary during portions of this period, although that will be
contingent on the rainfall and cloud coverage for any given
afternoon. Towards the end of the weekend and into early next
week, dew-points may drop a few degrees, although less cloud
coverage and rainfall could allow for more oppressive temperatures
through this period.

The National Hurricane Center continues to monitor an area of low
pressure in the western Caribbean Sea with a 20% chance of
tropical development over the next seven days. Readers are
reminded that a lot can change in the 7-10 day time-frame,
especially with the genesis and evolution of tropical systems.
While the general pattern for tropical development appears to be
favorable, it remains far too early to identify a potential track.
In simplest terms, while deterministic model solutions will vary
from run to run, it is very important to take them with several
grains of salt. Ensemble model plots (EPS and GEFS) may provide a
slightly clearer picture of what may unfold, however it is still
quite early. Regardless of what transpires, this is an important
reminder that we are in the midst of the peak of hurricane season.
Although the climatological peak of the Atlantic hurricane season
is on September 10th, the stretch of late September into the
first half of October is the climatological peak for hurricane
landfalls in South Florida. Remain weather aware, check hurricane
supplies, and most importantly, be sure to receive information
from reliable sources such as the National Hurricane Center, NWS
Miami, and local and national broadcast media sources.

&&

.AVIATION...
(18Z TAFS)
Issued at 210 PM EDT Wed Sep 18 2024

Scattered to numerous showers and storms will develop as the day
progresses. These storms could bring sub-VFR conditions to the east
coast terminals, mainly during the afternoon/early evening, and
short fused AMDs will be likely. At KAPF, winds will increase out
of the SW this afternoon as a Gulf breeze develops. Convection
should diminish later this evening with the focus returning over
the local waters overnight. Wind should lighten and again become
variable.

&&

.MARINE...
Issued at 210 PM EDT Wed Sep 18 2024

Generally light winds will prevail across the area through most of
this week as a weak surface boundary remains just to the north of
the area. Scattered showers and thunderstorms will be possible each
day through the period and could lead to locally higher winds and
seas.

&&

.BEACHES...
Issued at 210 PM EDT Wed Sep 18 2024

Minor to moderate coastal flooding will continue during periods of
high tide due to astronomically higher tides associated with the
full moon phase. Elevated tides will continue on both coasts of
South Florida through the end of the work-week.

Upcoming High Tide Times:

* Naples: 1:46 PM Wed, 1:52 AM Thu, 2:38 PM Thu
* Lake Worth: 9:01 PM Wed, 9:31 AM Thu, 9:49 PM Thu
* Port Everglades: 9:19 PM Wed, 9:50 AM Thu, 10:07 PM Thu
* Virginia Key:  10:04 PM Wed, 10:36 AM Thu, 10:51 PM Thu

Decreasing northerly swell will result in a lingering elevated
risk of rip currents for the Palm Beaches with a decreasing risk
along the Broward and Miami-Dade beaches in the coming days.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            77  90  75  89 /  50  70  50  60
West Kendall     74  90  74  90 /  50  70  50  60
Opa-Locka        77  91  75  90 /  50  70  50  60
Homestead        76  90  75  89 /  50  70  50  60
Fort Lauderdale  77  89  75  88 /  50  70  50  50
N Ft Lauderdale  77  90  76  89 /  50  70  50  50
Pembroke Pines   77  92  76  91 /  50  70  50  60
West Palm Beach  75  91  75  90 /  50  70  50  50
Boca Raton       76  92  75  90 /  40  70  50  50
Naples           78  90  76  90 /  40  50  30  40

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Advisory until 2 PM EDT Friday for FLZ069-075-168-
     172>174.

     Heat Advisory until 6 PM EDT this evening for FLZ071>074-172>174.

     High Rip Current Risk until 8 PM EDT this evening for FLZ168.

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

$$

SHORT TERM...RAG
LONG TERM....Hadi
AVIATION...RAG