Severe Thunderstorm Warning 381, NWS Tallahassee, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
326 PM EDT THU JUL 30 2015

.Near Term [Through Tonight]...

Convective development through 1830Z has closely mirrored the
forecasts of most of the convection-allowing models. Thus far,
storms have been focused on the Florida Big Bend sea breeze, and are
slowly propagating further inland, while isolated storms have been
observed elsewhere. The convective coverage should continue to
increase across the area as the afternoon progresses, with storms
likely to linger until the mid-to-late evening. Likely PoPs (60-70%)
have been maintained in all areas. With very high precipitable water
values (up to 2.4" near Gulf County on SPC mesoanalysis) and high
freeing levels, heavy rain rates in storms and locally heavy
rainfall appear likely this afternoon. A few storms could produce
strong-severe wind gusts, but the severe weather threat should
remain somewhat isolated.

Temperature trends today have also been close to expectations now
that the denser cloud cover from this morning has scattered out. A
few locations may see heat index readings reach around 110 degrees,
but most areas should top out in the in the 105-108 range. Lows
tonight look to be in the mid-70s.

.Short Term [Friday Through Saturday Night]...

Friday begins with an upper ridge exiting the Southeast to the
west, and a broad trough covering the northern third of the
country, but also dipping down the eastern CONUS just short of the
Southeast. At the surface, a frontal boundary will be draped
northeast to southwest from the NC coast to the LA coast,
essentially bisecting the Southeast. Out ahead of the front
remains the broad surface low/trough that has been aiding in
convective development over the past few days. These features will
move very little through Saturday night.

PoPs will remain higher than typical for this time of year with
the two primary focus areas being the front (NW half of the area)
and the broad low pressure (SE half of the area). High PWATs
between 2-2.25" and deep warm cloud layers (12-15 kft) each day
would suggest the potential for heavy rain. In addition, although
there are small differences in the steering flow between models,
it is probable that steering flow may run parallel to each of the
forcing mechanisms making training and isolated urban flooding a
concern. The threat for severe weather remains low, with only
an isolated damaging wind potential likely attributed to water
loaded downdrafts.

Highs will still be able to reach at least the lower 90s, and
possibly middle 90s in a very moist boundary layer. Thus, heat
advisory conditions are not out of the question tomorrow, but for
now heat indices appear to top out just below criteria. Slightly
cooler temps on Saturday will likely preclude heat advisory
conditions.

.Long Term [Sunday Through Thursday]...

The wet pattern will continue through the extending with the
persistent surface trough entrenched across the Southeast. PoPs
will remain above normal, with near to slightly below normal
afternoon highs.

&&

.Aviation...
[Through 18Z Friday]

Scattered to numerous thunderstorms are expected to affect the
region this afternoon and early this evening. Any of the terminals
could be affected by storms, which could bring brief gusty winds
and IFR visibilities in heavier downpours. Otherwise, primarily
VFR conditions are expected overall, although some brief MVFR
ceilings could occur early this afternoon. There is a chance for
some patchy fog overnight, but confidence is not sufficiently high
to put that in the TAFs yet.

&&

.Marine...

Southwest winds will become more westerly late in the weekend,
with high rain chances both day and night over the next several
days. On and off cautionary level winds will be possible east of
Apalachicola beginning Friday and lasting through early next week.

&&

.Fire Weather...

No red flag conditions are forecast for the next week with hot and
humid summertime conditions in place.

&&

.Hydrology...

Five day estimated rain totals indicate that 3 to 4 inches is
likely along the coast, especially in the southeastern Big Bend.
Elsewhere, 1.5 to 2.5 inches is likely. Area rivers are still
below action stage. With the heaviest rainfall expected near the
coast, river flooding is not expected; though isolated urban
flooding maybe possible in training or stationary storms.

&&

.Preliminary Point Temps/PoPs...

Tallahassee   76  92  76  92  75 /  40  60  50  60  40
Panama City   79  89  78  88  78 /  40  60  50  50  40
Dothan        75  94  74  93  74 /  40  60  50  50  30
Albany        75  95  75  93  74 /  40  60  40  60  40
Valdosta      74  93  75  92  75 /  30  60  30  60  40
Cross City    75  90  75  89  76 /  30  60  60  60  60
Apalachicola  79  90  78  88  77 /  40  60  40  50  40

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AL...NONE.
GM...NONE.
&&

NEAR TERM...LAMERS
SHORT TERM...HARRIGAN
LONG TERM...HARRIGAN
AVIATION...LAMERS
MARINE...HARRIGAN
FIRE WEATHER...MOORE
HYDROLOGY...MCDERMOTT/HARRIGAN