Area Forecast Discussion
Issued by NWS Charleston, SC
FXUS62 KCHS 231355
Area Forecast Discussion
National Weather Service Charleston SC
955 AM EDT SAT JUL 23 2016
High pressure will gradually shift offshore and persist through
much of next week.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
No major changes were made for the late morning update. Upper
ridging and extensive mid-level dry air will help limit the
coverage of showers/tstms over land this afternoon. Still expect
isolated convection to fire along/head of the resultant later
today. 20% pops are reasonable, although locally higher pops may
be needed if enough mesoscale boundary collisions occur. An
isolated strong/severe tstm can not be ruled out given the
elevated DCAPE in place. Highs in the mid-upper 90s are on track
away from the beaches.
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
Tonight: Generally dry after early evening convection wanes. Low
temperatures will range from the mid 70s inland to closer to 80 at
Sunday through Tuesday: Relatively stagnant synoptic pattern
expected early next week. The forecast area will remain under the
influence of broad mid/upper level ridging through the period. At
the surface, Atlantic high pressure will prevail while a weak
piedmont trough sits inland. Convective initiation will largely be
driven by the sea breeze and mesoscale boundaries with no larger
scale forcing mechanisms in play. Coverage should remain fairly
limited given subsidence and dry mid levels, and current forecast
features only slight chance PoPs in the afternoon and evenings.
Organized severe threat is low, however isolated severe storms are
possible especially where boundary interactions occur.
High temperatures mainly in the mid 90s will combine with dew points
in the low 70s to yield heat indices 103-106 each afternoon. Thus no
heat advisories are expected. Lows in the mid to upper 70s.
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
Little change in the weather pattern expected through late week,
with the primary surface features being Atlantic high pressure and a
weak piedmont trough. Fairly typical summertime PoP scheme, with
shower/thunderstorm coverage peaking in the afternoon and evening
when instability is greatest. No more than 20-30% chances warranted
at this time. Temperatures forecast to be above normal through the
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions are expected to prevail at KCHS and KSAV through
12Z Sunday. Isolated showers and thunderstorms are expected this
afternoon, mainly 17-21Z, as the sea breeze pushes inland but
chances are also too low to include.
Extended Aviation Outlook: Brief flight restrictions possible with
Today and Tonight: High pressure will remain in control with winds
mainly 15 kt or less, greatest near the coast this afternoon due
to the sea breeze. Seas will be a mix of around 9 second swells
and shorter period wind waves, with significant wave heights
mainly 3 feet or less, highest near the Gulf Stream. Also,
conditions look pretty favorable for waterspouts again this
morning within the nearshore waters along any cumulus lines
associated with the land breeze. Thus, a Marine Weather Statement
has been issued to highlight.
Sunday through Thursday: Rather benign conditions expected over
the waters through mid week. Atlantic high pressure will persist
while a weak trough sits inland. This will maintain a
south/southwest flow over the marine zones. Speeds generally at or
below 15 knots, peaking in the afternoon with the sea breeze
circulation and again overnight due to nocturnal jetting. Seas 2-3
feet on average.
Rip Currents: Buoy and coastal webcams indicate 9-10 second
swells have reached the beaches. Still anticipate a high-end low
risk for rip currents this afternoon given the lack of a
significant uptick in winds along the developing sea breeze, but
if winds do end up stronger than expected, a quick upgrade to a
moderate risk could be needed for some beaches, especially
Charleston County beaches.