Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 192028
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
428 PM EDT Fri Sep 19 2014
.Near Term [Through Tonight]...
Vapor imagery and upper air data showed a developing short wave
trough over the Southeast, with its axis across our forecast
area. Fairly strong Q-G forcing near and east of this trough,
along with sufficient deep layer moisture and marginal
instability, were helping to generate scattered showers &
thunderstorms across GA and north FL. The large area of mostly
light rain over the northeast Gulf of Mexico has persisted into
this afternoon. The showers and storms over land will gradually
dissipate by midnight, but low clouds will develop across much of
the region by dawn. Lows will be in the upper 60s.
.Short Term [Saturday Through Sunday Night]...
The aforementioned digging shortwave trough will likely close off
as a mid-upper level low briefly on Saturday near the NE Florida
or Georgia coastline, before ejecting northeast as another,
stronger digging trough pushes into the Northeast US from late
Saturday and into Sunday. The result will be slowly rising mid-
upper level heights across our forecast area, with a weak surface
pressure pattern or small bubble high. For Saturday, much of our
forecast area will be in an area of relatively strong QG
divergence to the west of the trough axis / mid-upper level low.
Although that would suggest more limited rain coverage, we will
remain in a region of fairly strong, 10-20 knot ENE boundary layer
flow, which is a pattern that tends to favor convection arriving
late in the afternoon from the east. Convection-allowing models do
show that, mainly in the form of rain showers, and so we included
rain chances over the eastern half of the forecast area, mainly
for the period from 20Z to 02Z. We are mostly anticipating low-
topped rain showers, although a few thunderstorms will be
possible. Highs should range from the mid-80s west, to the low 80s
east where there should be greater cloud cover.
As the mid-upper level shortwave trough and accompanying surface
low along the Atlantic coast eject northeast, quieter and dry
weather is expected on Sunday. With sunny skies, a return to the
upper 80s for high temperatures is likely.
.Long Term [Monday Through Friday]...
Not much has changed with respect to the expectations for next
week from our forecast yesterday. There is still some run-to-run
model inconsistency with the upper level flow pattern over the
CONUS, but models largely agree on an extended period of low-level
easterly flow for our area. There is likely to be a surface high
centered over or near the Northeast US, and we will be on the
southern periphery of the surface ridge. Therefore, some small
rain chances are likely to persist through the week, with
temperatures slightly below normal.
[Through 18Z Saturday] Scattered SHRA/isolated TSRA will develop
this afternoon & evening, with the highest PoP around KABY &
KVLD. Brief periods of MVFR VIS/CIGS are possible with the
showers; otherwise VFR conditions are expected. MVFR to IFR CIGS
are likely to develop overnight and early Saturday, with the
lowest CIGS expected at KVLD. These CIGS will be slow to lift
An area of surface low pressure over the east-central Gulf is
contributing to strong easterly winds at this time over much of
the central and eastern Gulf coastal waters. The offshore buoys
recently observed 20+ knot sustained winds, and this is most
consistent with high-resolution model guidance thus far. Those
high-res models indicate that 20-25 knot winds will become more
established through the late afternoon and evening in our offshore
waters. For now, we have issued a Small Craft Advisory beyond 20
NM from shore until 14Z, with a SCEC headline in nearshore waters.
However, given that the better verifying models at this time show
the possibility of 20 knot winds within 20 NM of shore later
tonight, this will have to be monitored closely for a possible
expansion of the advisory. Winds and seas should diminish
tomorrow. Another front will arrive on Tuesday with a subsequent
increase in E/NE winds again.
No fire weather concerns are expected for the next several days.
Generally light rainfall amounts are expected for the foreseeable
future, except in very localized instances. Therefore, we are not
expecting any significant flooding issues over the next week.
.Preliminary Point Temps/PoPs...
Tallahassee 68 84 68 88 66 / 40 30 30 10 10
Panama City 72 87 71 88 71 / 30 20 20 10 10
Dothan 67 85 66 88 66 / 20 10 10 10 10
Albany 68 84 65 89 65 / 20 20 20 10 10
Valdosta 67 83 65 88 64 / 30 50 30 10 10
Cross City 67 85 66 88 66 / 40 40 30 20 10
Apalachicola 73 84 71 86 71 / 30 20 30 10 10
GM...Small Craft Advisory until 10 AM EDT Saturday for Waters from
Suwannee River to Apalachicola FL from 20 to 60 NM-Waters
from Apalachicola to Destin FL from 20 to 60 NM.