Severe Thunderstorm Warning 22, NWS Miami, FL

Area Forecast Discussion
National Weather Service Miami FL
1249 PM EDT Mon May 5 2025

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

...Strong to Severe Thunderstorms SE Florida This Afternoon...
...Main Threats are Large Hail and Damaging Wind...

.SHORT TERM...
(Rest of today through Tuesday)
Issued at 1240 PM EDT Mon May 5 2025

A slow-moving deep layered low pressure system over Tennessee and
Kentucky has a trough which extends south into the eastern Gulf. At
the surface, a stationary front lies across Central Florida. South
of the front, a weak ridge is across South Florida. The low pressure
system is expected to move north over the next 24-36 hours, finally
lessening its influence on South Florida's weather, with a shortwave
mid/upper level ridge building into our area on Tuesday.

Similar to yesterday, the influence of the deep layered low pressure
will contribute to a few strong to severe thunderstorms this
afternoon across portions of South Florida. Colder air aloft
(exemplified by -22C at 400 mb from the morning Miami sounding) is
leading to mid-level lapse rates of 7 to 7.5 C/km. Dewpoints at
midday are in the lower to mid 70s, noticeably higher than the past
several days. Plenty of morning sunshine will result in highs
reaching the upper 80s to lower 90s most areas before convective
initiation, with CAPE values around 2500 J/kg this afternoon. These
parameters are more conducive for strong to severe storms compared
to yesterday, with the only potential limiting factor is drier
mid/upper level air. Model consensus is for thunderstorms to develop
early this afternoon along a zone from the central Everglades to
western suburbs of Palm Beach County, generally along the
convergence of the east and west coast seabreezes, and the Lake
Okeechobee breeze in Palm Beach County. Storm motion will be
generally NE-E, but with the slightly stronger SE low level winds,
the bulk of the convection should concentrate over the interior. As
was the case yesterday, outflows will propagate away from the storms
and lead to redeveloping convection over interior SW Florida as well
as closer to the east coast metro areas. Also, with 25-35 knots of
westerly mid-level winds opposing the low level SE winds, there
could once again be cold pools which could enhance backbuilding
convection along mesoscale boundaries. The main hazards for this
afternoon are large hail and damaging wind, and accordingly SPC has
upgraded the severe thunderstorm risk to Slight/Level 2 of 5. There
is also a significantly lower (but non-zero) threat of a tornado.

From a rainfall/flooding perspective, backbuilding and slow-moving
storms have the potential of dropping as much as 2-4 inches in
localized areas this afternoon and early evening, favoring interior
locations but not totally ruling out portions of the east coast
metro with a localized flood threat. Thunderstorms could linger as
late as 8-10 PM this evening before dissipating.

Lingering surface moisture and light winds overnight should set the
stage for patchy fog over interior South Florida, lasting until
shortly after sunrise Tuesday.

After a few late night/early morning showers over the near-shore
waters of both coasts, the setup for Tuesday looks to favor less
instability as the ridge aloft builds in and mid/upper level
temperatures rise. Temperatures in the upper 80s to lower 90s and
dewpoints remaining mostly in the 70s will provide enough
instability for scattered afternoon thunderstorms. As low level SE
winds become more established across South Florida, favored areas
for thunderstorms will shift westward to over interior SW Florida as
opposed to the eastern half of the peninsula. This is reflected in
the highest PoPs and QPF over those areas. A couple of stronger
storms may still occur on Tuesday, but not expected to be as intense
as the previous 2 days.

Another result of the building ridge on Tuesday is increasing
temperatures, with max temps well into the lower 90s over inland
SW Florida. This coupled with dewpoints in the lower 70s will
result in heat index values in the 100-103F range for a few hours
across these areas. These are the highest heat index values in
quite a while, so persons are advised to use extra caution to
protect themselves against the heat. Elsewhere, heat index on
Tuesday will top out in the lower to mid 90s.

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 220 AM EDT Mon May 5 2025

Overall drier weather through Thursday and Friday as mid-to-upper
level ridging rebuilds back into the area from the south and weak
surface high pressure sits over the Gulf and western Atlantic.
Minimal shower chances are expected each day, mainly in the
afternoon and evening hours during peak diurnal heating and when
the sea breezes advance inland. By the weekend, a slow moving
upper level trough will approach the northern Gulf. Moisture
advection will occur at this point as South Florida will be in the
southeast quadrant of the system, which will usher in extra
moisture from the Caribbean via southerly low level and surface
flow. Dew points could rise into the 70s on a daily basis,
resulting in a more unstable atmosphere and bringing higher
chances of showers and thunderstorms back to South Florida
each day from Saturday through the end of the forecast period.

Temperatures will remain slightly above normal across the east coast
metro with highs in the middle 80s, and above normal over interior
and SW FL with highs each day in the upper 80s to lower 90s. Lows in
the 60s/70s are expected each night, with the warmest overnight
lows near the Atlantic coast.

&&

.AVIATION...
(18Z TAFS)
Issued at 1240 PM EDT Mon May 5 2025

TSRA developing over the peninsula and expected to affect MIA-
FLL-PBI corridor in the 19z-01z time frame. Expect occasional MVFR
and brief IFR conditions along with wind gusts 35 knots or higher
to affect at least a few of the terminals. KAPF will remain
precip-free and VFR through the period. TSRA dissipating, with
mainly VFR conditions after 02z, with only isolated SHRA or TSRA
for remainder of forecast period. Wind SE 10-13 knots, except SW
seabreeze at KAPF through 01z.

&&

.MARINE...
Issued at 1240 PM EDT Mon May 5 2025

High pressure will slowly rebuild over the local waters this week,
with prevailing winds out of the SE at 10-15 knots and seas
generally less than 4 ft. The main threat over the local waters will
be showers and thunderstorms, primarily this afternoon and tonight,
causing locally higher wind and seas.

&&

.BEACHES...
Issued at 1240 PM EDT Mon May 5 2025

The rip current risk will remain low for most of the week as SE
winds be mainly less than 15 mph. As is the case with the local
waters, the primary beach threat will be lightning and locally
strong wind gusts during the afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...
Miami            75  86  75  86 /  50  20   0  10
West Kendall     71  89  72  89 /  40  20   0  10
Opa-Locka        74  89  74  89 /  50  20   0  10
Homestead        74  86  74  86 /  40  20   0  10
Fort Lauderdale  74  85  75  84 /  60  20   0  10
N Ft Lauderdale  74  85  74  85 /  60  20   0  10
Pembroke Pines   76  90  76  90 /  50  20   0  10
West Palm Beach  72  86  73  86 /  60  20  10  20
Boca Raton       74  87  74  86 /  60  20  10  20
Naples           71  89  71  88 /  10  40  10  20

&&

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

SHORT TERM...Molleda
LONG TERM....Redman
AVIATION...Molleda