Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 281130
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
730 AM EDT Wed Jul 28 2021

.AVIATION...
Scattered showers and isolated thunderstorms are already popping up
over west central and southwest Florida this morning. Will hold VCTS
at all terminals through the day. Some brief periods of MVFR/IFR may
be possible in heavier showers and storms, cut overall VFR is
expected. Winds will be out of the west at 10 knots of less, except
in the vicinity of thunderstorms where gusty winds will be
possible.

&&

.Prev Discussion... /issued 331 AM EDT Wed Jul 28 2021/

DISCUSSION...
A strong U/L ridge over the central plains extends to the
southeast U.S. bridging with another area of high pressure over
the western Atlantic. An U/L disturbance will push across New
England today with an associated L/W trough digging down the
eastern seaboard. The southern extent of the trough will cause a
break/weakness in the ridge over the Florida peninsula...and the
slight lowering heights will decrease large scale subsidence over
the peninsula allowing convection to be enhanced today and
Thursday.

The U/L ridge over the central plains will build southeast over
the Florida peninsula Thursday night and Friday...and will hold
over the area on Saturday. An anomalously strong U/L disturbance
for late July will dive out of central Canada and push across the
Great Lakes and Northeast Sunday and Monday with the southern
extent of the associated U/L trough digging over the southeast
U.S. and Florida Sunday and Monday which will again breakdown the
ridge over Florida...which will hold over the region through the
middle of next week.

At the surface, overall pattern will be a broken record with west
to southwest boundary layer flow through the entire forecast
period. This will promote scattered late night/early morning
showers and thunderstorms developing over the coastal waters,
advecting onshore typically around sunrise. Thunderstorm activity
will increase over the coastal counties during the morning and
early afternoon hours, spreading inland and increasing in areal
coverage through the remainder of each day. Main differences in
day-to-day sensible weather and coverage will be slight changes in
U/L large scale subsidence based on changes in heights over the
forecast area. The persistent onshore flow will also create very
warm muggy uncomfortable conditions each day with overnight
temperatures struggling to drop to around 80 near the coast. High
temperatures each day will generally run from 90 to 95 with upper
80s along the coast.

Deep tropical moisture is currently over the region with TBW
28/00Z sounding coming in with a healthy 2.31 inches PCPW.
Winds aloft are also very weak as from the surface through almost
100MB winds were 15 knots or less through the entire column. This
will create ideal conditions for very slow moving storms. Combine
this with the high PCPW values and storms today and Thursday will
be capable of producing very heavy rain and localized flooding.
Unstable atmosphere currently over the area will lead to scattered
to numerous showers/thunderstorms developing over the coastal
counties this morning/early afternoon gradually spreading inland
through the day.

AVIATION...
Numerous showers and thunderstorms today with LCL MVFR CIGS
020-025 and IFR VSBYS may impact all terminals for a few hours
today. Most likely timing TPA/PIE/SRQ/PGD/FMY/RSW 08-17Z...and
LAL 15-20Z.

MARINE...
Weak gradient across the waters will keep winds less than 15 knots
and seas less than 3 feet through the period. Main hazard will be
scattered predominately nighttime showers and thunderstorms which
will be capable of producing locally gusty winds and rough seas.

FIRE WEATHER...
No fire weather hazards are expected for the next several days as
relative humidity values are expected to remain above critical
levels.

&&

.Preliminary Point Temps/PoPs...
TPA  92  81  93  82 /  70  40  60  30
FMY  92  78  94  79 /  60  30  50  20
GIF  92  78  93  78 /  70  40  60  30
SRQ  89  79  91  79 /  60  30  40  30
BKV  91  75  91  75 /  70  40  60  20
SPG  89  82  91  82 /  70  30  60  40

&&

Sea Breeze Thunderstorm Regime For Today: 4
Sea Breeze Thunderstorm Regime For Tomorrow: 4

For Additional Information On Sea Breeze Regimes go to the link below
https://www.weather.gov/tbw/ThunderstormClimatology

&&

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

&&

$$

AVIATION...74/Wynn
DECISION SUPPORT...57/McMichael


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