Damaging Winds in Florida, June 24, 2021

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
151 PM EDT Thu Jun 24 2021

.SHORT TERM (Rest of Today through Friday)...
The morning KTBW sounding was quite moist through the column,
with PW values around 1.75", so certainly the potential for heavy
rainfall with our storms in to the evening hours. Otherwise, the
sounding parameters were not all that favorable for severe storms
given marginal lapse rates, and little in the way of drier air
below 500mb. 500mb temps are also right about where the should be
for this time of year. Obviously, any given storm needs to be
watched for more mesoscale environmental factor contributing to
updraft strength, but the potential for significant severe seems
low today.

We do see a little in the way of upper support to enhance storm
coverage later today in the form of an upper inverted trough
migrating from east to west over the peninsula. We will be on the
western side of this energy today and then underneath or just east
of the axis for Friday. Storms, once they develop today, will be
migrating generally east to west or northeast to southwest toward
the coast. Those at the beach or especially boating over the
coastal waters should be aware of this offshore movement and
prepare to seek safe harbor quickly if the skies to the east or
northeast begin to darken. Lightning is still our greatest day to
day weather threat, and it does not take strong or severe
thunderstorms to produce deadly lightning.

Storms begin to push off the coast and diminish within a couple of
hours post-sunset this evening. By 11pm or so, the forecast
becomes generally dry for the remainder of the evening over land,
with a few residual storms possible over the coastal waters.

As discussed above, some low end synoptic support for enhanced
storm coverage will continue in the vicinity on Friday, although
late in the day as the axis of this trough exits over the eastern
Gulf of Mexico, there should be some drying of the column. Hard to
say, but the drying is likely not going to be significant enough,
or occur too late to really allow for any suppression of storm
potential. Therefore, overall rain chances remain high.

.LONG TERM (Saturday through next Thursday)...
We will end up in a very persistent pattern for the majority of
the upcoming week as high pressure remains centered well to our
north. The distance of the ridge axis from our area will keep the
gradient fairly tight for late June...with 10 to 15 knots of
easterly flow in the lower levels of the atmosphere. This pattern
from a climatological sense if favored for showers and storms each
day to be most enhanced along the Florida west coast / I-75
corridor. The issue/question each day will be if the synoptic flow
is too strong to allow the sea-breeze to develop, or if it does,
will it be able to penetrate inland at all. It may be a scenario,
from a pure convergence argument that the best rain chances will
be right at the beaches.

Within the fast flow, we are likely to see minor vorticity centers
aloft that could help fire storm away from the best sea-breeze
convergence zones, and this makes the forecast a bit more
difficult to put high levels of detail in each day beyond the
weekend. The elevated southeast flow is typically associated with
high rain chances, but low rain totals, as storms tend to move
quickly. This is how the forecast will run for much of next week.
High rain chances, but not necessarily, significant rain amounts
in any one spot.

&&

.AVIATION...
Scattered showers are starting to develop across west-central and
southwest florid. The easterly wind pattern suggests the best
chances for storms occurs 18Z to 22Z for Fort Myers area, and
generally 20Z and beyond for the Tampa Bay Area terminals. Storm
motion will be generally from the east/northeast to the
west/southwest. Storms will pass off the coast within an hour or
two post sunset, with a generally quiet night with light variable
or easterly winds. Generally quiet and VFR conditions persisting
into the morning daylight hours of Friday, with renewed
thunderstorm activity moving east to west across the peninsula
after 18Z.

&&

.MARINE...
High pressure parked well to the north of the region will provide
a long duration east to southeast wind flow over the eastern Gulf
of Mexico. Winds are likely to slacken or briefly turn onshore at
the coast each afternoon, but then quickly resume an easterly
direction around sunset. Scattered to numerous showers and storms
will be in the forecast in this pattern throughout the week.
Mariners will have to watch out for these storms during the early
morning hours...and then again late afternoon and early evening as
the land based storms move offshore into the Gulf.

&&

.FIRE WEATHER...
Minimum relative humidity values remain well above critical levels
through the duration of the upcoming week. A large scale east to
southeast wind flow suggests decent chances for wetting rains
from passing storms each day...although mainly in the afternoon
and evenings.

No significant areas of fog are anticipated.

&&

.Preliminary Point Temps/PoPs...
TPA  76  89  77  92 /  60  70  20  60
FMY  74  91  75  92 /  60  70  20  70
GIF  74  88  75  90 /  50  60  20  70
SRQ  74  89  74  92 /  60  70  30  60
BKV  70  89  71  92 /  60  70  20  60
SPG  76  87  77  90 /  60  60  30  60

&&

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