Area Forecast Discussion
Issued by NWS Jacksonville, FL
FXUS62 KJAX 301957
Area Forecast Discussion
National Weather Service Jacksonville FL
356 PM EDT TUE AUG 30 2016
..Increasing chances of TD #9 to impact the local area Thu
through early Fri...
.NEAR TERM...TD#9 continues to develop over the eastern Gulf of
Mexico near 24n87w this aftn while locally broad inverted sfc
trough is positioned over the FL peninsula. Fairly strong low
level convergence along the coastal areas is noted and continues
to shift a little northward this afternoon and was focused mainly
over coastal SE GA at 19z. For this evening...isolated to
scattered showers expected inland with numerous showers possible
for the coastal areas overnight tonight. A few tstms will be
possible in the evening...then anticipated to be confined along
the coast tonight where greater instability.
.SHORT TERM /Wednesday through Friday/...
An inverted surface trough will bisect the region extending to current
TD 9. The tropical depression is forecast to strengthen in a
tropical storm later today. Waves of showers and isolated
thunderstorms will push across the region throughout the day from
southwest to northeast. An upper level trough will push across the
Great Lakes and northeastern conus through short term. This will
create a weakness along the east coast and over our region, and
allow TD 9 to push north and northeastward across the northeastern
Gulf of Mexico on Wednesday night and Thursday. The models are in
very good agreement with this scenario. The models have shifted
further north, slowed down, and come in with a little lower
pressure on the 12Z runs, with landfall in the northern part of
the big bend region of Florida or as far north as the Panhandle
Thursday evening or Thursday night. The models then track the
system to the northeast across southeast Georgia and then off the
coast across southeast GA to somewhere near the SC/GA border
Friday morning or afternoon.
Conditions are forecast to quickly deteriorate on Thursday as the
system approaches the region from the northeast Gulf. 0-1km
helicity values are forecast to increase to 200-300 m2/s2 Thursday
afternoon and Thursday night and isolated tropical tornadoes are
possible region-wide. Widespread rainfall of 3-6 inches is
forecast across the region, with amounts of 6-10 inches for
counties closer to the Gulf coast in the Suwanee Valley. Locally
higher amounts are possible near the center and where training
rain bands setup. Tropical storm conditions are possible across
much of the region Thursday and Thursday night and into Friday
Highs on Wednesday and Friday will be in the mid to upper 80s across
northeast Florida and upper 80s to low 90s across southeast
Georgia. Highs on Thursday will likely remain in the low to mid
80s across much of the region due to cloud cover and heavy
rainfall. Overnight lows will be in the low to mid 70s.
.LONG TERM /Friday Night through Monday/...
TD 9 should be moving well northeast of the region Friday night.
A tail of showers may linger behind the system across a portion of
the region Friday night and the storm will help push a weak cold
front through the region on Saturday. Drier low/mid level air and
northeasterly flow will develop over the weekend and continue
through early next week. Highs will be in the low to mid 80s along
the coast, and the upper 80s to lower 90s inland. Overnight lows
are forecast to be in the mid 60s to near 70 inland and the low to
mid 70s along the coast.
.AVIATION...Sct to numerous showers and isolated tstms expected
this evening with chance of MVFR CIGS/VSBY. In any stronger shower
activity, IFR VSBY will be possible. By after 00z...most of the
convection will become focused over the coastal waters and coastal
TAF sites for SSI and CRG with VCSH for rest of the TAFs. Chance
of MVFR CIGS at all TAFS for Wed morning.
.MARINE...East to southeast winds tonight near 15-20 kt will
shift to southerly direction as sfc trough lifts northward and
possible weak low forms and lifts north over the coastal waters.
Seas mainly in the 4-6 ft range nearshore and up to 6-8 ft
offshore through tonight. SCA conditions appear likely for the
offshore waters so will headline SCA through Wed morning...with
SCEC headline for the nearshore waters.
Winds will become south to southwest near 15-20 kt over area
waters Wed as a trough axis moves northward over the region ahead
of TD #9. TD #9 is expected to track across the northeast Gulf of
Mexico Wed and then across N FL and the adjacent coastal waters
Thu-Thu night...then exiting northeast of the local waters Fri.
Tropical storm force winds will be possible during this time
period in squalls. A trailing front will push south of the area
late Fri or Sat with high pressure building NE of the region this
Rip Currents: High risk continues today. Breakers in the 3-5 ft
range possible along the NE FL coast today.
.PRELIMINARY POINT TEMPS/POPS...
AMG 72 91 75 86 / 20 50 40 70
SSI 77 87 76 84 / 50 60 60 80
JAX 74 89 76 84 / 50 70 60 90
SGJ 76 86 76 84 / 60 70 60 90
GNV 74 86 75 82 / 50 70 70 90
OCF 74 85 75 82 / 50 70 70 90
FL...High Rip Current Risk until 8 PM EDT this evening for Coastal
Duval-Coastal Nassau-Flagler-St. Johns.
GA...High Rip Current Risk until 8 PM EDT this evening for Coastal
AM...Small Craft Advisory until 11 AM EDT Wednesday for Waters from
Altamaha Sound GA to Fernandina Beach FL from 20 to 60 NM-
Waters from Fernandina Beach to St. Augustine FL from 20 to
60 NM-Waters from St. Augustine to Flagler Beach FL from 20
to 60 NM.