941
FXUS62 KTBW 181128
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
728 AM EDT Thu Jul 18 2024

...New AVIATION...

.SHORT TERM...
(Today and tonight)
Issued at 341 AM EDT Thu Jul 18 2024

As a deep trough passes to the north, ridging remains in place
across the Florida peninsula. The center of this surface ridge axis
remains situated across the Central FL peninsula, with light and
variable flow in place across the region once again today. This most
closely resembles a regime 1 setup today. Lacking a dominant flow,
sea breeze movement will be sluggish, favoring higher POPs along the
FL West Coast - not unlike the last few days

Today`s limiting factor is some mid-level dry air that is present
once again. However, it didn`t end up being a significant barrier to
convection yesterday and doesn`t look to be all that impactful once
again today. Water vapor satellite imagery also suggests a fair
amount of this dry air is being scoured out. Assuming thunderstorms
develop much like they did yesterday, there is a higher potential
for downbursts this afternoon. Forecast DCAPE is exceeding 1000 J/KG
during the afternoon hours. As convection grows deeper in the late
afternoon, the risk becomes higher. It is not particularly high, but
enough that it is worth noting. With such a light flow, storm
motions are going to be almost nonexistent, which means locally
heavy rainfall is possible. Additionally, storms will produce
frequent lightning as they grow deeper in the afternoon.

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 341 AM EDT Thu Jul 18 2024

As the trough axis centered over the Upper Great Lakes lifts
northward back into Canada, the suppressed ridge axis will build
back west. In response, the subtropical ridge will shift farther
west as well. A stronger ESE flow will then setup in response for
Friday and over the weekend, much like regime 6. Climatologically,
this doesn`t have a huge impact on our weather. The West Coast
remains favored for thunderstorms in the afternoon and evening as
the stronger ESE flow delays sea breeze development and pins it
near the coast. However, there is another patch of Saharan Dust
being carried westward by the trade winds. It looks like this
could also begin to impact our area beginning on Saturday. Dust
tends to limit convective activity as the air becomes drier; but
this has the tradeoff of potentially enhancing storms that do
develop, allowing for an elevated wind risk. With fewer storms, it
also means less relief from daytime heat in the afternoon.
Questions still remain about just how much and how impactful dust
could actually be, though. Global models are not showing much
influence at this time. The forecast continues to show max daytime
POPs of 55% to 65% each day.

Aside from some slight day-to-day variability with some drier air
and/or fluctuations in wind speeds with the mean flow, there is
really no significant change in pattern until the very end of the
forecast period when a weak upper-level disturbance enters the
scene. This Tropical Upper Tropospheric Trough (or TUTT) could lead
to earlier and enhanced rain chances with the return of SW flow for
next Thursday, perhaps lasting a couple days beyond and towards next
weekend.

In summary, a typical summertime pattern will continue. Expect warm,
humid mornings, afternoon storms, and quiet evenings. Late next
week, the timing could shift earlier, but still is in line with
typical patterns for this time of year.

&&

.AVIATION...
(12Z TAFS)
Issued at 725 AM EDT Thu Jul 18 2024

A light mainly SE flow this morning will gradually shift onshore
later today as the sea breeze pushes inland with winds becoming
more WNW at coastal terminals. In addition, scattered showers and
storms are expected to develop later today with greatest precip
chances expected to occur from around 19Z-23Z so brief IFR
restrictions may occur depending on how close in proximity this
activity is to aerodromes. Otherwise, precipitation activity will
taper off after around 01Z/Friday with light/VRB winds expected
overnight.

&&

.MARINE...
Issued at 341 AM EDT Thu Jul 18 2024

A light and variable flow will continue across coastal waters today,
with some shower and thunderstorm activity expected this morning
and into the afternoon. The highest winds and seas should be
expected in the vicinity of storms. However, as an ESE flow
settles in and becomes stronger on Friday, thunderstorms over
land are more likely to drift over nearshore coastal waters in the
late afternoon and into the evening through the middle of next
week. While the background flow will be come slightly stronger,
the expectation is little change in surface wind speeds. Seas
remain around 1 foot or less outside thunderstorms.

&&

.FIRE WEATHER...
Issued at 341 AM EDT Thu Jul 18 2024

While some slightly drier air is present in the mid-levels, this
does not appear to be a significant barrier to thunderstorm
activity. Scattered to numerous storms are forecast once again
today, with the highest coverage expected this afternoon and into
the evening as the sea breeze develops. However, the flow is light
and variable, meaning that dispersions are low. A slightly stronger
ESE flow begins to settle in tomorrow, raising dispersions during
the afternoon. Additionally, slightly drier air could arrive this
weekend. However, storms are still forecast and RH values will
remain well above critical thresholds. No significant fire weather
concerns exist at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
TPA  93  80  93  79 /  60  30  70  40
FMY  93  77  93  78 /  70  40  70  30
GIF  95  77  95  77 /  50  40  70  20
SRQ  93  78  93  78 /  50  40  70  40
BKV  95  75  95  75 /  50  30  70  40
SPG  94  82  93  82 /  50  40  70  50

&&

Sea Breeze Thunderstorm Regime For Thursday: 1
Sea Breeze Thunderstorm Regime For Friday: 6

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

&&

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

&&

$$

SHORT TERM/LONG TERM/MARINE/FIRE WEATHER...Flannery
AVIATION...Giarratana
DECISION SUPPORT...Hubbard
UPPER AIR/CLIMATE...Hubbard