Scientific Forecaster Discussion
fxus62 kchs 250202
Area forecast discussion
National Weather Service Charleston SC
1002 PM EDT Fri Mar 24 2017
high pressure will prevail this weekend. A weak cold front should
stall over the area during the middle of next week, then shift
back north as a warm front late in the week.
Near term /until 6 am Saturday morning/...
the 3.90 um satellite images still showing the remnants of the
controlled burn earlier in Berkeley County near Bethera and
Farewell Corner. At the request of the US Forest Service in
the Francis Marion nf, a dense smoke advisory has been issued
through 10 am Saturday. For the time being all roads are open,
but portions of several roads in northern Berkeley County may be
A deep onshore fetch and decent low level moisture beneath the
nocturnal inversion will support considerable stratocumulus from
the Atlantic advecting onshore and impacting mainly the coastal
zones through the night. Also, high level cirrus will continue
to arrive from the northwest, and the combination will result
in partly co mostly cloudy skies.
A few hi-res models do indicate a little fog west of I-95 closer
to daybreak, but with geostrophic winds at 10 kt or greater and
the cirriform clouds, this is highly unlikely.
Sfc high pressure centered to the northeast will slide further
east over the western Atlantic while a low pressure system
advances east over the central United States. Aloft, a high
amplitude ridge of high pressure will extend across the
southeast for much of the night, dominating the weather pattern
with dry/mild conditions.
Temps are running about 65-10f higher than this time last night,
and with a southeast synoptic flow and the cloud cover, temps
tonight will be quite a bit warmer than recent nights. Figure on
50-55f far inland and mid to upper 50s on the coast, in downtown
Charleston and on the shores of Lake Moultrie.
Short term /6 am Saturday morning through Monday/...
the region will remain along the western fringes of Atlantic high
pressure through the period. Weak shortwave energy and the approach
of a weakening cold front could support scattered showers/tstms
Sunday afternoon with another round of convection possible Monday
afternoon ahead of the resultant sea breeze circulation. Pops will
be capped at 30-40% inland both days with coastal pops limited to
20%. Highs away from the beaches will warm into the mid-upper 70s
Saturday, the lower 80s Sunday with lower-mid 80s Monday. Lows will
range from the mid-upper 50s inland with lower 60s at the coast each
Long term /Monday night through Friday/...
a weakening cold front looks to approach the area mid week before
stalling and eventually shifting back northward as a warm front late
in the period. Some showers and thunderstorms are expected, mainly
Mon night into Tuesday and again Friday as a shortwave energy moves
through the area. No significant rainfall and/or severe weather
anticipated at this time however.
Aviation /02z Saturday through Wednesday/...
VFR, although there is a risk for a period of MVFR ceilings late
tonight and Saturday morning at kchs and ksav as maritime
moisture becomes trapped beneath a sharp inversion.
Extended aviation outlook: there are no impact-level concerns
with a >30% probability of occurrence.
tonight: a very subtle inverted trough oriented generally north
to south across the coastal waters will persist, as a 1033 mb
high north of Bermuda ridges westward across the Carolina's.
This pattern will feature east-southeast winds at or below 10 or 15 kt.
But despite the lack of significant wind, seas within the long
duration onshore fetch will still be as high as 3 or 4 ft, even
up to 5 ft across the outer Georgia waters.
Saturday through wednesday: there are no concerns with Atlantic
high pressure generally in control until a weakening cold front
moves into the area Wednesday. Seas look to be near 6 feet along the
eastern portions of the Georgia offshore leg which will likely
necessitate a Small Craft Advisory for that zone. Winds will remain
less than 20 kt through the period.
SC...dense smoke advisory until 10 am EDT Saturday for scz045.