Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tampa Bay Ruskin Florida
429 am EDT Wednesday Aug 20 2014
Short term (today - thursday)...
strong high pressure will remain in control of the weather pattern
today and Thursday...with the middle level ridge currently stretched
from the Bahamas through the southern and central Florida Peninsula
and into the eastern Gulf of Mexico. Through tonight and
Thursday...this ridge will shift to the west as a strong longwave
ridge builds into the lower Mississippi River valley. At the
surface...the ridge axis is positioned across southern
Florida...resulting in onshore flow north of Tampa Bay. Under this
pattern...a few showers can be expected to develop over the
northeastern Gulf this morning and move into the Nature
Coast...however a dry atmospheric column should keep these showers
minimal. Despite the dry air and subsidence being supplied by the
ridge...isolated to scattered storms should be able to find a way to
develop this afternoon under strong surface heating...with the
highest chances over southwest Florida and interior west central
As the middle level ridge shifts west on Thursday...a bit more moisture
will be able to return to the Florida Peninsula...with chances for
scattered thunderstorms possible at almost any location...especially
away from the immediate coast.
The ridge will also keep temperatures well above normal...with maximum
temperatures reaching into the middle 90s across the interior...and
heat index values peaking as high as 106.
Long term (thursday night-tuesday)...
latest model solutions are back in decent agreement after some big
differences in the previous runs. The middle/upper level ridge will
continue to strength over the lower Mississippi Valley late in the
week then drift north into the Tennessee Valley over the weekend as
a deepening trough develops and cuts off over the western Atlantic
Ocean. At the surface...the high pressure ridge axis across the
region Friday will become suppressed south over the weekend as a
back door cold front moves down the eastern Seaboard and eventually
stalls over North Florida early next week. Meanwhile the GFS and now
even the latest European model (ecmwf) try to develop the elongated area of low
pressure (96l) as it moves westward through the Caribbean Sea and
eventually into the south central Gulf of Mexico by the middle of
next week. Will have to wait and see how things evolve over the next
few days...but present indications are that this system would
continue moving west northwest staying well to the south and west of
the forecast area.
For Thursday night through Saturday the overall flow will remain
rather light west to northwest with the sea breezes developing each
afternoon. Moisture will be slowly increasing during this time so we
should see isolated to scattered convection develop mainly during
the afternoon and early evening each day. Temperatures will remain
near to slightly above normal through Saturday with overnight lows
in the middle 70s inland to around 80 along the coast...and daytime
highs in the lower to middle 90s...except upper 80s along the immediate
For Sunday into the first half of next week deep moisture will
return as the boundary approaches from the north and this will
combine with daytime heating and the sea breezes to cause scattered
to numerous mainly afternoon and evening storms each day.
Temperatures will be closer to normal during this time with
overnight lows mostly in the 70s and daytime highs in the upper 80s
to lower 90s.
generally VFR conditions will continue through the next 24 hours.
The possible exception will come from isolated to scattered
thunderstorms that develop this afternoon...with the best chances in
the vicinity of krsw...kfmy...kpgd...and klal.
high pressure centered over the eastern Gulf of Mexico will keep
winds below 15 knots and seas less than 2 feet into the weekend.
Thunderstorm chances will also remain minimal for the next couple of
days with little more than isolated showers and a few
thunderstorms...but increasing moisture this weekend will bring rain
chances back to around normal.
humidity levels will stay well above critical levels...with no fire
weather concerns this week.
Preliminary point temps/pops...
tpa 93 79 93 80 / 10 10 20 20
fmy 95 78 94 78 / 30 20 40 20
gif 95 77 96 77 / 20 10 30 10
srq 93 78 93 77 / 10 10 20 20
bkv 94 71 96 74 / 10 10 30 20
spg 92 80 92 82 / 10 10 20 20
Short term/aviation/marine/fire weather...18/Fleming
long term/decision support...69/close