Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston SC
1231 am EDT Tuesday Jul 26 2016
Atlantic high pressure will prevail through much of the week while
a weak trough persists inland.
Near term /until 6 am this morning/...
another warm night is underway under deep layered ridging. Min temps
will be some 3-5f above typical late July norms as winds decouple
inland, but remain a little elevated along the coast. Skies will
be clear or mostly clear within large scale subsidence to prevail.
Short term /6 am this morning through Thursday/...
a persistent weather pattern is in place as strong Atlantic
mid/upper-level ridging extends across the southeast and a weak
trough remains far inland. Pwats are generally under 2 inches, which
is close to normal for this time of year, but more noticeable is the
lack of instability across our area each afternoon (capes struggling
to reach 1,500 j/kg). This will limit the convective potential and
coverage. Have trimmed pops to only a small portion of our Georgia
counties Tuesday afternoon, where some convection across northern Florida
could move northward. The slight chance pops remain in the forecast
mainly along the sea breeze corridor and inland Wednesday and
Thursday. Early morning land-breeze formation will likely result in
some convergence along and just off the coast each morning. Storms
forming along this boundary should remain isolated and weak with a
couple of waterspouts the primary concern.
Temperatures will remain above normal due to the warm airmass
already in place, west-southwest flow through the low/mid levels and subsidence
aloft allowing for plenty of sunshine through midday each day. Heat
indices will top out in the mid to upper 100s each day, with a few
areas possibly near 110 degrees briefly in the afternoon before the
sea breeze moves through and lowers them.
Long term /Thursday night through Monday/...
hot and humid conditions will continue through the weekend as
ridging persists overhead and Atlantic high pressure remains at the
surface. A weak cold front may approach from the north Friday or
Saturday, but will likely dissipate before reaching the area.
Afternoon thunder chances across land areas, and morning thunder
chances over the waters, trend closer to climo in the long range,
with dry air/subsidence aloft gradually moderating through the
weekend. High temps will continue to reach the mid-to- upper 90s
away from the immediate coast through the weekend assuming minimal
debris clouds and convection abates until mid-to- late afternoon
A pattern change could come as early as Monday as weak upper level
troughing begins working into the eastern U.S.
Aviation /06z Tuesday through Saturday/...
VFR through 06z Wednesday, with little or no chance of any
convection this afternoon.
Extended aviation outlook: VFR will prevail at both sites. Brief
flight restrictions possible with isolated afternoon
showers/thunderstorms mainly late week.
overnight: conditions across the marine area will be relatively
quiet under the influence of Atlantic high pressure. On the latest
update we lowered initial wind speeds in the Charleston Harbor,
otherwise the forecast is on track.
Tuesday through saturday: Atlantic high pressure will allow south to
southwest at 10-15 kt to prevail. Gusts around 20 kt are expected
with the afternoon sea and overnight land breezes. Seas will range
from 1-3 ft, except some occasional 4 footers across the outer
Georgia waters. We'll maintain a close surveillance for
waterspouts each morning through the period on convergent cloud