Area Forecast Discussion
Issued by NWS Charleston, SC
FXUS62 KCHS 270123
Area Forecast Discussion
National Weather Service Charleston SC
923 PM EDT FRI AUG 26 2016
High pressure centered to the north will prevail into Monday. Low
pressure may then occur nearby during the middle to late part of
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Friday was the 66th day in a row of 90 degrees or greater at
Tonight: A deep and solid anticyclone remains anchored over a good
chunk of the eastern third of the nation, with it`s associated
surface ridge from the Atlantic also overhead. Other features of
noted interest include a very weak mid level impulse rotating
around the ridge aloft that is causing a batch of stratocumulus
that is nearing the outer GA waters, the remnants of Fiona to the
south of Bermuda, and weak low pressure (Invest 99-L) between Cuba
and the central Bahamas. Although the perturbation over the ocean
will head west, there is still considerable dry air in place, so
this activity should diminish before making too much headway
toward the coast. Instead, with an easterly synoptic flow and
minor isentropic ascent there could be some stratocumulus that
move onshore overnight, especially for coastal GA. But overall
conditions favor mainly clear or at worst partly cloudy skies.
Temps will be similar to last night, with about an 8-10 degree
spread from the "cooler" far inland spots to the "warmer" beaches
and in downtown Charleston.
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
Saturday: Dry conditions will persist as deep layered high
pressure holds firm. A few low-topped showers could move onshore
across the Georgia coast in the east/northeast low-level flow,
but coverage should remain fairly isolated. Forecast soundings
depict a fairly large capping inversion which will limit updraft
strength quite a bit. This should curtail the tstm potential. The
risk for isolated showers moving onshore along the Georgia coast
will linger through the night. Highs will range from the lower-mid
90s inland to the upper 80s near the coast. Lows will from the
lower-mid 70s inland to around 80 at the beaches.
Sunday through Monday: A more active convective pattern will
ensue during this period as the upper ridge buckles in response
to the remnant mid-level circulation left over from Tropical
Storm Fiona moving inland along the Southeast U.S. coast. Lower
heights aloft coupled with increasing low-level moisture and
inland convergence in the vicinity of a weak surface rough will
support scattered convection each day. Activity will likely
initiate near the coast during the morning hours then propagate
and/or redevelop inland as the each day progresses. Some
nocturnal activity is possible Sunday Night as well, mainly at the
coast, but most of the convection will remain diurnal in nature.
Pops will be capped at 30-40% for now, but higher pops may
eventually be needed, especially inland. Highs each day will range
from lower 90s inland with mid 80s at the beaches. Lows Sunday
Night will range from the lower-mid 70s inland to around 80 at the
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
There is still fairly high uncertainty this period as much depends
on the strength/track of low pressure which is expected to be in the
eastern Gulf of Mexico to start the period. Stuck with NHC/WPC
guidance for the most part which indicates the low moving across
the eastern Gulf of Mexico and into the Florida Panhandle by late
in the week. This should lead to increased cloud cover, better
rain chances and temperatures closer to normal as a weak surface
trough lingers inland.
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Extended Aviation Outlook: There will be an increased risk of
flight restrictions in showers/possible thunderstorms through the
middle of next week depending on the track of low pressure which
is likely to be in the eastern Gulf of Mexico early next week.
Tonight: Elongated high pressure from the Atlantic waters off the
Delmarva and extending over the SE will dominate the local waters.
E winds as high as 12-16 kt this evening will back some 20-40
degrees late due to the cooling effects of the land as speeds drop
several knots. The wave spectrum will favor short period wind
waves, averaging 2-3 ft north and 3-4 ft south.
Saturday through Tuesday: High pressure centered north of the
area will prevail into Monday before giving way to a weak trough
moving into the area ahead of low pressure in the eastern Gulf of
Mexico. This pattern will favor east/northeast winds mainly 15 kt
or less with some higher gusts, especially across the GA waters
beyond 20 nm. Seas will slowly build from 2-4 ft to 3-5 ft into
early next week. Conditions will to remain below small craft
advisory thresholds, although with increasing swell, conditions
could get a little rough at times near the entrances to bays,
rivers, inlets and harbors.
Rip currents: The leading edge of a long period swell training
generated by Tropical Storm Gaston will reach the waters Saturday
and continue into early next week. NWPS Gerling-Hanson plots for
buoys 41033 and 41029 show swell periods reaching 10-11 seconds by
Saturday afternoon. This will support a moderate rip current risk
at all beaches. Periods are forecast to reach as high as 11-15
seconds Sunday into Monday, thus an enhanced risk will remain in
Tides are expected to remain higher than normal given the persistent
onshore winds and could reach high enough to produce minor saltwater
inundation in the typical areas along the lower South Carolina coast
during the late day high tide cycles into early next week. Coastal
Flood Advisories may be needed.
Top 5 Warmest August`s on Record (Based on Average Monthly
KCHS (Records date back to 1938)...
1. 2016...84.1 (through August 26)
KSAV (Records date back to 1874)...
2. 2016...84.7 (through August 26)
KCXM (Records date back to 1893)...
5. 2016...83.8 (through August 26)