Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 121921
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
321 PM EDT Fri Sep 12 2014
.Near Term [Through Tonight]...
Deep layer ridging and a relative minimum in PWATs (and mid-level
moisture) has thus far kept convective activity suppressed through
19Z across much of our forecast area. This is expected to
continue through mid afternoon, although most models do generate
some isolated to scattered thunderstorms from late this afternoon
into the evening hours. Convection-allowing models are in good
agreement in showing some storms lingering several hours after
sunset. Because of these trends, we focused the best rain chances
(as high as 30-40%) from around 22Z to 06Z. Otherwise,
temperatures should continue to be a few degrees above normal for
this time of year.
.Short Term [Saturday Through Sunday Night]...
Although the upper level pattern will feature an elongated east-
west upper level ridge across the area, a weak surface boundary
will get pushed into the area as a strong surface ridge builds
across the middle part of the country. Deep moisture is expected
to pool along this boundary with an increase in convection likely
for Saturday afternoon, especially across the western portions of
the area. In addition, with precipitable water values rising to
near 2 inches and weak steering flow, some localized heavy
rainfall amounts could occur, again most likely mainly west of a
Tallahassee to Albany line.
Deep moisture will linger across the area on Sunday, but there
appears to be less of a focusing mechanism for convection compared
to Saturday, so PoPs are expected to be more uniform across the
area in the 40-50% range. High temperatures are expected to be
mainly in the lower 90s with lows in the low to mid 70s.
.Long Term [Monday Through Friday]...
The main uncertainty for the extended forecast is to what extent
the weak system moving westward into the Gulf will impact our
area. The collaborated NHC/WPC forecast takes the system westward
to a position south of Houston by mid-week and keeps it weak. Deep
moisture will continue to increase across the area with a stalled
frontal boundary also in the vicinity. These ingredients point to
an unsettled period coming up with an above average chance of rain
by mid-week. Some locally heavy rain is possible given the weak
boundary and deep tropical moisture expected to be in place. This
could be further enhanced by the Gulf system depending on its
evolution, but that evolution is much more uncertain. Daytime
highs are expected to be held down in the mid 80s from Tuesday
through most of the week given the expected cloud cover and
increased rain coverage.
[Through 18Z Saturday] VFR conditions should generally prevail
over the next 24 hours. Some isolated to scattered showers and
thunderstorms may develop late this afternoon and linger into the
evening hours, primarily 22-06Z. VCTS was included in this set of
TAFs, with the best chances for thunderstorms at ABY and DHN. If a
thunderstorm directly affects one of the terminals, a brief period
of IFR VIS will be possible. Showers and storms should diminish
later tonight. Just beyond the end of this TAF period - Saturday
afternoon - thunderstorm coverage is expected to be higher than
what we are likely to see today.
A weak pressure gradient is expected to remain in place through
most of the period with winds and sea fairly low. Winds will
increase some offshore on Saturday as a weak low passes well south
of the area.
Relative humidity values will remain above 35 percent through next
week with no red flag conditions expected.
Although widespread heavy rainfall is not expected through the
weekend, some localized heavy amounts could occur with deep
moisture in place and a weak frontal boundary sliding south into
the area. The most likely areas to see locally heavy rain on
Saturday will be west of a Tallahassee to Albany line.
Looking ahead into next week, deep tropical moisture is expected
to be in the area along with a weak frontal boundary and the
possibility of a weak low in the Gulf. These ingredients will have
to be monitored closely for the potential of some heavy rain by
.Preliminary Point Temps/PoPs...
Tallahassee 73 92 73 92 72 / 20 40 30 40 30
Panama City 77 91 75 90 75 / 20 60 40 40 30
Dothan 72 91 72 90 72 / 40 70 50 50 30
Albany 73 92 72 92 73 / 40 60 50 50 30
Valdosta 71 92 71 92 71 / 20 30 30 40 30
Cross City 71 92 71 91 71 / 20 30 30 40 30
Apalachicola 75 89 75 89 75 / 20 40 30 40 30