Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 011945
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
345 PM EDT TUE SEP 1 2015
.Near Term [Through Tonight]...
An elongated area of low pressure with a large area of convection is
evident on satellite and radar imagery this afternoon about 100
miles south of Tallahassee. Fortunately, this system is expected to
move inland late tonight into Wednesday morning before it has a
chance to develop further. Rain will be most likely across the
southeast big bend and just offshore through the remainder of this
afternoon and into the overnight hours. Overnight lows are expected
to be in the low to mid 70s across the area.
.Short Term [Wednesday Through Thursday Night]...
Above-average rain chances will persist through Wednesday, at least
across the FL Big Bend, south-central GA, and north FL, as the
remnants of Erika translate slowly northward. PoPs will range from
20% around Dothan and Panama City, where the airmass remains
considerably drier, to 70% around Valdosta, Madison, and Perry.
Scattered mainly afternoon and evening thunderstorms are expected
Thursday region-wide. Our PoP is 40% for much of the area, which is
only slightly above climo. This number may trend up a bit in
subsequent forecasts as there may be some additional Q-G forcing mid-
upper layer trough approaches from the west. Temperatures will be
seasonably warm this period, with highs in the lower 90s and lows in
.Long Term [Friday Through Tuesday]...
The 12z GFS and ECMWF are in better agreement than 24 hours ago, as
they forecast a broad area of lower 500 mb heights over our region
for much of this period. PoPs will be slightly above-average (40-
50%) through the weekend, then tail off a bit next week as slightly
drier air in the boundary layer advects into the region on the
western flank of a weak low pressure system off the Southeast coast.
Temperatures will remain near average, with lows in the 70s and
highs near 90.
[Through 18Z Wednesday] Scattered convection is expected to be
near VLD through the early evening hours, and a period of MVFR to
IFR conditions is possible there late tonight. Otherwise, mainly
VFR conditions are expected to prevail.
We were fortunate enough to get a 1630 UTC ASCAT pass over our
marine area to augment our sparse observation network. The data
showed that the remnants of Erika, though weak in terms of pressure,
had a closed circulation with wind speeds at advisory levels across
portions of the northeast Gulf of Mexico. The 15 UTC HRRR appeared
to have the best handle on this system (based on its
initialization), so we weighted it more in our forecast for
overnight. Convection aside, we expect "exercise caution" winds in
Apalachee Bay tonight, then winds weakening Wednesday morning as the
center of the low moves inland. Afterwards, winds and seas will be
Relative humidity values will remain in the upper 40s or higher
through Thursday. In addition, winds are forecast to remain less
than 10MPH and thus hazardous fire weather conditions are not
expected through Thursday.
The heaviest and most organized rain is expected across portions of
the FL Big Bend from this evening through Wednesday. Rain amounts
will be around an inch east and south of Tallahassee, and less than
a quarter of an inch elsewhere. Isolated rain amounts up to 4 inches
are possible, which could cause localized flooding if it occurs in
the wrong place (i.e. urban areas, small streams, etc.). Our rivers
were all below their local action stages, and the latest hydrologic
ensembles forecast this to continue for the next several days.
.Preliminary Point Temps/PoPs...
Tallahassee 74 91 74 93 75 / 50 60 30 40 30
Panama City 76 88 77 88 76 / 10 30 10 40 30
Dothan 73 93 73 92 73 / 0 20 10 40 30
Albany 74 92 74 93 74 / 10 40 10 40 20
Valdosta 73 90 73 92 74 / 40 70 30 40 30
Cross City 75 90 74 91 75 / 60 50 30 40 30
Apalachicola 75 89 77 90 77 / 40 40 20 40 30
FL...HIGH RIP CURRENT RISK until Midnight EDT tonight FOR Coastal