970
FXUS62 KTBW 142353
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
753 PM EDT Tue May 14 2024

...New UPDATE, AVIATION...

.UPDATE...
Issued at 710 PM EDT Tue May 14 2024
Brief reprieve this evening as the forecast area is between
systems. A former MCS over the central Gulf of Mexico/loop
current has rapidly dissipated during the past few hours as it
moved east toward the eastern Gulf. Residual high cloudiness is
currently spreading over west central and southwest Florida and
will persist for the next several hours.

Otherwise, a frontal boundary will approach north Florida
overnight with a band of showers and thunderstorms redeveloping
across north Florida and the northeast Gulf of Mexico around or
shortly after midnight as the atmosphere gradually destabilizes.
There is a slight chance for severe thunderstorms across Levy
county where BWD will be in the range of 30 to 40 knots late
tonight and a LLJ of similar strength, along with mid level CAA
with a pocket of 50T`s in the -9 to -11 range advecting across the
region. This will create conditions favorable for damaging wind
gusts and hail with stronger updrafts.

The boundary/line of showers and storms will sink very slowly
south late tonight and Wednesday as it will be nearly parallel to
the U/L flow. A marginal risk for severe storms will extend across
the central Florida peninsula associated with the
boundary mainly due to the mid level cold pocket, daytime heating
increasing convective instability, and sustained LLJ. However, it
appears that the best U/L support will be exiting east of the area
which will be an inhibiting factor and should lead to decreasing
areal coverage/weakening trend.  Would suspect best chance for
stronger storms would be over the interior during the afternoon
hours, if a west coast sea breeze boundary is able to develop and
push inland due to the southwest flow...which would aid in
creating additional boundary collisions.

&&

.DISCUSSION...
Issued at 253 PM EDT Tue May 14 2024

A shortwave trough continues to advance eastward across the
Mississippi Valley today with the associated trailing cold front
stretching southward into the Gulf of Mexico. A series of impulses
embedded along the southern periphery of the trough continue to
bring clusters of storms from the Gulf of Mexico across the Florida
peninsula with a line of storms that moved through earlier and
brought reports of severe wind gusts is now moving off the Atlantic
coast as well as another cluster of storms currently in the east-central
Gulf. Despite recent satellite imagery showing an organized cloud
shield with cloud tops as cold as around -70C, latest CAMs
generally show a weakening trend with this feature as it
approaches the west central FL coast by this evening but a brief
severe risk may exist if this activity can hold together enough.

The next and more likely severe risk will occur on Wednesday as the
trough shifts east and pushes a southward sagging cold front into
central Florida where this frontal boundary will eventually stall.
In addition to the frontal boundary, strong westerly winds aloft of
80+ kts at 300mb will move across the area and this will increase
deep layer shear with 0-6 km bulk shear values around 35-45 kts.
This combined with good CAPE values as high as 3000 J/kg and 500mb
temps around -10C will support scattered to numerous convection
across the region with potential for damaging wind gusts, hail, and
a few tornadoes and/or waterspouts. In addition to the severe risk,
WPC has placed much of the region in a Marginal risk of excessive
rainfall and while previous 30 day rainfall observations compared to
percent of normal are generally in the lowest 10th-25th percentile
(or even less in isolated areas), the westerly flow aloft should
align well with the west-to-east oriented frontal boundary to
possibly support training of storms. Regardless, this will be an
opportunity for very needed rain across much of the area, especially
areas that haven`t receive too much precipitation in recent days but
we be monitoring for any training/flooding potential, which would be
rather localized if anything does occur at all.

Transient ridging moves across the area by Thursday and this will
bring a decrease to rain chances with PoPs less than 15% from Tampa
Bay northward, though isolated to scattered storms will be possible
for southern portions of the forecast area where deeper moisture
will exist and interacts with the lingering frontal boundary. This
frontal boundary then lifts north as a warm front by Friday as low
pressure system in the central US shifts across the OH valley and
drives the next cold front towards the area for the upcoming
weekend. As a result, PoPs will be on the increase once again over
the weekend as models show this frontal boundary approaching late
Saturday into Sunday. Despite a possible frontal passage by early
next week, a model consensus of PoPs still supports precipitation
chances into the end of the forecast period as troughing aloft may
linger over the area, though it appears overall precipitation
coverage should still be on a decreasing trend into early week.

&&

.AVIATION...
(00Z TAFS)
Issued at 710 PM EDT Tue May 14 2024
VFR conditions expected this evening at all terminals. A few
showers may develop late tonight/early tomorrow morning vcnty
PIE/TPA with LCL MVFR CIGs/VSBYs. A band of showers/thunderstorms
will approach PIE/TPA/LAL tomorrow afternoon with LCL MVFR CIGs
and IFR VSBYs. Otherwise VFR CIGs will prevail. Southern terminals
will remain VFR tonight and Wednesday.

&&

.MARINE...
Issued at 253 PM EDT Tue May 14 2024

Several more storm clusters are expected to move across the Gulf
waters with the next round possibly occurring this evening,
though there remains uncertainty with how much of this activity
will hold together. However, a cold front will gradually push
southward across the region with scattered to numerous showers and
thunderstorms spreading from north to south throughout the day.
Some of this activity to produce strong winds, waterspouts,
lightning, and torrential downpours. In addition, small craft
exercise cautionary levels will be possible on Wednesday outside
of thunderstorms as gusty southwest winds will be in place
throughout the day. Winds then decrease late week as weak high
pressure builds in with decreasing rain chances, though another
cold front will arrive by next weekend with increasing
precipitation chances once again.

&&

.FIRE WEATHER...
Issued at 253 PM EDT Tue May 14 2024

Storm clusters will continue to move across the area ahead of a
cold front with the next cluster possibly approaching the area
this evening. However, better rain chances area-wide will occur
on Wednesday as a cold front gradually pushes southward across the
region with scattered to numerous showers and thunderstorms as
well as needed rainfall to many areas. Drier weather then returns
late week as weak high pressure builds in with minimum RH values
dropping into the upper 30 percent range for interior areas,
though red flag conditions are not expected at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  77  86  76  88 /  50  90  20  10
FMY  79  91  77  91 /  10  50  40  40
GIF  74  88  72  92 /  40  70  20  10
SRQ  77  88  76  89 /  40  70  40  10
BKV  71  87  67  90 /  60  80  10  10
SPG  79  85  78  87 /  50  90  30  10

&&

Sea Breeze Thunderstorm Regime For Wednesday: 5
Sea Breeze Thunderstorm Regime For Thursday: 5

For additional information on sea breeze regimes, go to:
     https://www.weather.gov/tbw/ThunderstormClimatology

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.

&&

$$

UPDATE/AVIATION/MARINE/FIRE WEATHER...Oglesby
DECISION SUPPORT...Hurt
UPPER AIR/CLIMATE...Hurt