Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 020650
Area Forecast Discussion
National Weather Service Tallahassee FL
250 AM EDT SAT JUL 2 2016
.NEAR TERM [Through Today]...
The 10 pm EDT regional surface analysis showed a quasi-stationary
front across central GA and AL, and a high pressure ridge along the
FL Peninsula. Vapor imagery and upper air data showed a weak short
wave trough axis across our forecast area, separating sinking,
drying, northwest winds west of the trough axis from moist southwest
winds to the east of the axis. Although the NWP guidance does not
depict significant Q-G forcing with this trough, its separation of
moisture, coupled with mesoscale boundary forcing (such as the north
FL sea breeze front and outflow boundaries) will be the main driver
of today`s PoPs.
There is good agreement among the various MOS and CAMs in developing
scattered showers across the FL Big Bend coastal waters in the pre-
dawn hours this morning, and that these showers will become more
numerous and intense during the daytime hours as they spread
eastward across north FL. The highest PoPs (50-60%) will be around
Perry, Cross City, and Mayo, mainly this morning and early
afternoon. Elsewhere, where the mid layers of the troposphere will
be warm and dry, PoPs will be 20% or less. Highs will be in the mid
to upper 90s across the northwest two-thirds of the forecast area,
and mid to upper 80s across north FL, where cloud cover and rain
will keep temperatures a little "cooler".
.SHORT TERM [Tonight Through Monday]...
The upper level trough that had been in place over the southeastern
CONUS much of the past week will continue to retreat northward
during this period, resulting in zonal flow across the Ohio River
Valley and Mid-Atlantic regions and a building ridge over the
southeastern states. At the surface, high pressure will also build
over our area throughout this period. However, dry air that had
been present at mid-levels will decrease and PWAT values will
return to typical values for this time of year, generally between
1.5" and 2.0" across our area.
The ample moisture along with moderate instability (around
1000-2000 J/kg of surface based CAPE) will lead to the development
of isolated/scattered showers and thunderstorms across our area during
the afternoon and early evening on Sunday and Monday. Tonight and
Sunday night will be mostly dry across our area without forcing from
the sea breeze. Similar to the precipitation chances, temperatures
will be fairly typical for this time of year. Highs in the low-mid
90s and lows in the mid 70s are expected inland, with highs in the
upper 80s and lows in the upper 70s along the coast.
.LONG TERM [Monday Night Through Saturday]...
The upper level ridge is expected to intensify across our area
during this period, with high pressure also prevailing at the
surface. Model guidance is showing a slight warming trend
throughout the week, and some solutions have locations in southeast
Alabama and southwest Georgia reaching/exceeding 100 degrees from
Thursday through Saturday. Hotter than average temperatures seem
reasonable, considering 700 mb to 1000 mb standardized temperature
anomalies from the NAEFS ensemble are frequently above the 90th
percentile late in the week. However, with seasonably moist
conditions persisting (PWAT values between 1.5 and 2" throughout
the period) and forcing from the sea breeze each afternoon/early
evening, some isolated/scattered convection will likely develop
each afternoon. This could prevent temperatures from reaching the
higher numbers suggested by some guidance, but highs in the mid-
upper 90s still appear likely from Wednesday through next weekend.
Combined with dewpoints in the low-mid 70s, this could result in
heat indices near 105 degrees each afternoon.
.AVIATION [Through 06Z Sunday]...
The latest consensus of NWP guidance has backed off considerably in
forecasting widespread IFR Vis overnight. Normally this time of year
there`s a high correlation between rain the afternoon/evening before
and subsequent morning fog, but much of Friday`s rain was not very
heavy and it occurred earlier in the day. We are now only
forecasting MVFR Vis around dawn at KVLD. Note that there still
could be patches of IFR Vis, but the probabilities of this occurring
have fallen below 20% for most areas except around KVLD (where it
was 40%). While numerous SHRA/TSRA are likely along the FL Big Bend
coast and north FL this morning and early afternoon, we expect our
TAF sites to remain largely free of storms, with VFR conditions and
light winds prevailing.
Winds from the southwest at 10 to 15 knots will prevail for the
next several days, resulting in seas of 2 feet or less throughout
There are no flooding concerns with the dry pattern expected over
the next several days.
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 76 94 76 94 76 / 20 40 10 20 10
Panama City 79 88 79 88 79 / 10 20 10 20 10
Dothan 75 96 75 93 76 / 10 10 0 20 10
Albany 75 96 75 95 75 / 10 20 10 20 10
Valdosta 75 94 75 95 75 / 20 40 10 30 10
Cross City 76 92 76 93 76 / 50 50 10 30 10
Apalachicola 79 88 79 90 79 / 30 40 20 20 10