Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tallahassee Florida
852 PM EDT Tuesday Sep 1 2015
Near term [through tonight]...
the remnants of Erika continue to bring rain to mainly The Big
Bend area. Based on radar trends, have cut back slightly on pops
across some of the marine zones but will have to expand the
mention of activity into some of the western portions of the County Warning Area.
Besides some tweaks to pops, temperatures are on track.
[through 00z thursday]...
convective activity has been diminishing across the taf sites this
evening and thus have left the mention out of rain showers/thunderstorms and rain for the
remainder of the night at most sites. Will need to watch tlh and VAD
though.This activity should increase again on wendesday in the late
morning into the afternoon across the eastern half of the taf sites.
While overall VFR conditions are forecast, except for a brief
decrease in visibility possible in convective activity, MVFR fog and LIFR
cigs are forecast for vld for the morning.
Prev discussion [345 PM edt]...
Short term [wednesday through Thursday night]...
Above-average rain chances will persist through Wednesday, at least
across the Florida 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 European model (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.
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 Florida 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 74 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 / 30 40 20 40 30
Florida...high rip current risk until midnight EDT tonight for coastal