Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 181355
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
955 AM EDT Sat May 18 2013
.NEAR TERM [Until 8 PM This Evening]...
Showers and thunderstorms are ongoing in association with a mid
level impulse that turned southeastward early this morning across
East Central Alabama. Questions remain as to whether this
convective complex will sustain itself long enough to have a
significant impact on our forecast area today. Already, a few showers
and storms have drifted into the northwestern portion of the area,
and recent trends from radar imagery across East Central Alabama
do show signs of reintensification of the storms.
The morning KTAE sounding does show some favorable thermal
profiles above 700 mb where the lapse rates are relatively
steep, on the order of 7.5 to 8 deg C/Km. However, moderate
heating is necessary today to really make full use of this
favorable profile aloft. A warm layer from about 850-700mb will
limit more robust updrafts early in the day until surface temps
reach the mid 80s.
High resolution guidance continues to have issues with this
particular system, but most show the cluster impacting Southern
Georgia through about 18z before diminishing through the
afternoon. While this seems plausible as diminished heating in the
northern counties will limit overall destabilization, areas to the
south, along the Florida border could see late day development as
mesoscale boundaries emanating from the convection across our
northern counties interacts with the sea breeze front. The
strongest storms today would have potential to produce some small
hail and gusty winds. The overall severe potential is low.
Made a few updates to the inherited forecast to favor greater rain
chances across the northern areas and indicate a more conditional
potential further to the south across North Florida.
.SHORT TERM [Tonight Through Monday]...
Very summerlike conditions are expected across the region for
both Sunday and Monday, as the shortwave Trof Axis, which will
begin the weekend to our north, gradually slides eastward to a
position off the eastern seaboard by Monday afternoon. This will
allow for Upper Level ridging to build in from the west, with High
Temps expected to reach the lower 90s each day over the interior,
with lower to perhaps mid 80s near the coast. This shortwave Trof
may provide just enough lift and instability to combine with the
daytime heating to produce isolated to scattered showers and
thunderstorms. The best chances for rain will be across eastern
portions of the CWA (nearest the Trof), but even here, 30% should
be the greatest value.
.LONG TERM [Monday Night through Friday]...
The 500mb ridge over the Southeast U.S. early in the work week will
transition to a weak trough by late week. The height falls over our
forecast area will be modest so only a slight increase in PoP is
expected later in the week. Until then, the GFS forecasts more deep
layer moisture (hence QPF) than the ECMWF for our region.
Climatologically it`s still a bit early for widespread mesoscale-
induced convection, so an average of the two solutions will get us
close to our climatological PoP (around 20%), with a diurnal
cycle. High temperatures will be at or a few degrees above
average, with lows near average (in the 60s).
.AVIATION [Beginning 14Z Saturday]...
See the Near Term discussion above for a synopsis of the evolution
of this mornings complex of storms. Generally VFR conditions will
prevail today once the morning ceilings scatter out. However,
expect MVFR ceilings and visibilities within areas of rain,
impacting primarily KABY and KDHN through midday. Overnight
tonight, expect more widespread low ceiling and fog development.
Generally light onshore winds and low seas will dominate our coastal
waters for the next several days, with just some minor enhancements
near the coast with the afternoon sea breeze.
Relative humidity values will remain above critical levels for the
next several days, with relatively light transport winds and deep
mixing heights. Thus, Red Flag conditions are not expected in the
Area rivers and streams will remain well below flood stage for the
next several days with very little rain in the forecast.
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 87 62 91 64 91 / 40 10 20 10 20
Panama City 81 67 84 68 85 / 30 10 10 10 10
Dothan 84 65 90 66 92 / 70 20 20 10 10
Albany 84 64 90 66 91 / 70 20 20 30 20
Valdosta 90 63 92 64 92 / 60 20 30 20 30
Cross City 88 63 88 65 89 / 20 10 20 10 30
Apalachicola 82 66 82 66 84 / 20 0 10 10 10