Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 281357
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
958 AM EDT Thu Aug 28 2014
The 12z KTAE sounding is very dry with a PWAT of 0.96", which is
about half of normal. The profile also shows mostly light and
variable winds through a deep layer as you would expect with stacked
high pressure. A few showers have developed offshore from the land
breeze but we don`t expect any convection over land areas today.
Highs will be above normal in the mid to upper 90s away from the
[Through 12Z Friday] Limited cloud cover is expected with VFR
conditions expected to prevail. Some brief MVFR VIS is possible
with fog at VLD closer to sunrise.
.Prev Discussion [258 AM EDT]...
.Near Term [Through Today]...
We will continue to be under the influence of a very dry air mass
and a weakening surface high pressure ridge today, which will lead
to another dry and mostly sunny forecast. Projected PWATs and
925mb mixing ratios at 18Z today are around the 1st percentile for
this time of year, or about 2.5-3.0 standard deviations below
normal. This degree of dry air should yield surface dewpoints in
the 50s, except near the coast. Despite widespread highs in the
mid-90s expected today, the unusually low dewpoints should make it
feel much less humid than is typical of late August. Lows tonight
will be slightly warmer than this morning, but mid-upper 60s are
still likely in many areas, particularly north of Interstate-10.
.Short Term [Tonight Through Saturday]...
Deep layer moisture will be advected northward on Friday in
advance of a shortwave moving into the Mississippi Valley. The
PoP will have a north to south gradient with the highest PoPs
(~60%) near the coast tapering down to just 20% across the
northern counties. Both the NAM and GFS show PWAT values rising
above 2 inches across the area on Friday and Saturday, so some
localized heavy rainfall rates and amounts are possible, but the
available forcing is not currently expected to be enough to
produce widespread heavy rain. High temperatures are expected to
be in the mid 90s, and with an increase in dewpoints, heat indices
are expected to reach the 100-105 range across the southern
portions of the area on Friday afternoon and across most of the
area by Saturday afternoon.
.Long Term [Saturday Night Through Thursday]...
The shortwave over the Midwest will gradually dampen out as it
lifts across the Great Lakes region. This along with additional
shortwave energy translating eastward from the western states will
effectively set up nearly zonal flow across most of the CONUS by
early next week. At the surface, the east to west ridge axis will
extend across or just north of our CWA with moist onshore flow
continuing. With a return of deep layer moisture along with
daytime heating and added instability, look for near to above
seasonal PoPs each day. Despite the increase in rain chances, max
temps will generally be above climo in the lower to mid 90s.
Light to occasionally moderate onshore winds and seas 3 feet or
less are expected to prevail through Labor Day.
A very dry air mass across the region and the recent development of
drought conditions over parts of the area may contribute to an
increased fire danger today. However, durations of low RH and wind
speeds are expected to be too limited to create red flag conditions.
Durations of RH below 28% in Leon County are expected to be around
2-3 hours, which is not sufficient for a Red Flag Warning. However,
ERC values are projected to be above 40, so Leon County could be
close to observing red flag conditions. Greater moisture will
return by Friday with higher RH values.
A significant increase in deep layer moisture is expected for
Friday into Saturday with scattered convection. Some locally
heavy rainfall rates and amounts are possible, but widespread
heavy rain does not look likely at this time.
.Preliminary Point Temps/PoPs...
Tallahassee 97 70 95 74 94 / 0 0 50 40 50
Panama City 91 75 90 77 90 / 10 10 60 40 60
Dothan 95 68 94 73 94 / 0 0 30 30 60
Albany 96 67 96 73 95 / 0 0 20 20 60
Valdosta 94 67 94 72 95 / 10 0 40 30 50
Cross City 94 70 93 73 94 / 10 10 50 40 50
Apalachicola 90 75 89 77 90 / 10 10 60 40 50