509
FXUS62 KMFL 131315
AFDMFL

Area Forecast Discussion
National Weather Service Miami FL
915 AM EDT Sat Jul 13 2024

...New UPDATE...

.UPDATE...
Issued at 907 AM EDT Sat Jul 13 2024

Convective activity is beginning to make its arrival along the
southeastern coast in Miami-Dade County. Thunderstorm activity
has been ongoing over the Atlantic throughout the early morning
hours. The cloud coverage, and it`s impact on the temperatures,
will have the determining factor on the heat advisory. Relatively
clear skies have allowed for a quickly warming morning, but the
incoming cloud coverage and potential showers will play a large
role in whether the temperatures continue to warm. The RH is
definitely there, but we will see how quickly this first line of
showers moves.

&&

.SHORT TERM...
(Today through Sunday)
Issued at 336 AM EDT Sat Jul 13 2024

A transient upper high hovers over the Florida peninsula, placing
South Florida in a weak easterly flow regime. Residual vorticity
maxima aloft from remnants of a weak upper-level disturbance may
continue to advect through the mean synoptic scale flow. This
setup could result in periodic increases in cloud coverage and
convective activity at atypical times. Expect a weak flow
convective regime, where areas with optimal juxtaposition of ML
CAPE and low-level forcing for ascent may experience pulse-type
convective cells, leading to localized flooding and nuisance
rainfall.

On Sunday, a strong Bermuda High and a mid-level ridge will shift
winds to a more easterly flow. Diurnally driven convection will
begin early along the eastern coast, with the highest rainfall
probabilities expected across southwestern Florida and the
interior by the latter part of the day. The presence of a warm air
mass and 500mb temperatures remaining in the -5 to -6 degrees C
range through the weekend will likely inhibit the development of
robust and severe thunderstorms.

Temperatures will be seasonable to seasonably warm. Expect maximum
temperatures generally between the upper 80s to mid 90s, with
possible heat index values reaching 106-107 degrees over portions
of Broward and Miami-Dade counties this afternoon. A Heat
Advisory is in effect for those counties from 10AM through 6PM
today.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 336 AM EDT Sat Jul 13 2024

An extension of the Subtropical Ridge centered over the Western
Atlantic will maintain deep easterly flow across the region. Embedded
within this easterly flow is a fast-moving tropical wave near the
Windward Islands, forecast to reach the Straits of Florida and
the Florida Keys early Monday. This wave will bring deep tropical
moisture, with precipitable water values around 2.3 inches (90th
percentile) and breezy east-southeast winds of 15-20 mph. The
arrival of the tropical wave and associated moisture will result
in numerous showers and thunderstorms, supported by sufficient
forcing and large-scale ascent. This may lead to atypical
convective activity that does not follow the diurnal cycle,
potentially causing heavy rainfall in short periods and localized
flooding.

There exists uncertainty in the forecast regarding the northern extent
of the moisture plume as it approaches our CWA. The ECMWF model
suggests a more southerly track, resulting in lower PWATs over the
area, while the GFS model indicates a more northerly track with
higher moisture content.

Temperatures are expected to remain near normal throughout the
long-term period. Daytime highs will climb into the upper 80s
along the east coast and lower 90s across the interior and west
coast. Overnight lows will settle into the mid to upper 70s inland
and on the west coast, and upper 70s to low 80s on the east
coast.

&&

.AVIATION...
(12Z TAFS)
Issued at 659 AM EDT Sat Jul 13 2024

Light and variable winds will continue at TAF sites until 14Z before
increasing to around 10-12 KT from the ESE throughout the day.
VCSH/VCTS expected after 13-15Z at TAF sites, starting on the east
coast, and will continue until around 00Z. Short-fused MVFR/IFR
periods possible with any passing activity. KAPF will likely
experience a westerly onshore flow with Gulf breezes during the
afternoon hours beginning around 16-18Z through 00Z. Overnight,
winds will become light and variable with activity backing off
until the morning hours.

&&

.MARINE...
Issued at 336 AM EDT Sat Jul 13 2024

Easterly flow will generally prevail through the weekend as high
pressure strengthens over the western Atlantic. Seas and wind speeds
will remain well below highlight criteria, ensuring overall
benign boating conditions through early next week. The only
exception will be near any thunderstorms that form, which could
bring brief periods of rough seas and gusty winds.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            92  81  92  81 /  60  40  60  30
West Kendall     92  79  92  79 /  60  40  60  30
Opa-Locka        92  81  93  81 /  60  40  50  30
Homestead        90  81  91  81 /  60  40  60  40
Fort Lauderdale  89  81  90  81 /  60  40  50  30
N Ft Lauderdale  91  81  91  81 /  60  40  50  20
Pembroke Pines   93  81  93  81 /  60  30  50  30
West Palm Beach  92  81  91  80 /  60  30  50  10
Boca Raton       91  81  91  80 /  50  30  50  20
Naples           92  79  93  78 /  70  40  60  30

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory until 6 PM EDT this evening for FLZ071>074-172>174.

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

$$

SHORT TERM...JS
LONG TERM....99
AVIATION...JS