Area Forecast Discussion
Issued by NWS Charleston, SC
FXUS62 KCHS 262022
Area Forecast Discussion
National Weather Service Charleston SC
322 PM EST Sun Feb 26 2017
High pressure will push off the East Coast through Monday. The high
will remain over the Atlantic through the middle of the week with
the forecast area under its western periphery. A cold front will
move through Wednesday night into Thursday, followed by more high
pressure for the end of the week.
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
High pressure will cover much of the E and SE parts of the
nation, with a modifying clockwise return flow from off the
Atlantic across the local district. Winds will quickly decouple
away from the coast this evening, allowing for a rapid fall of
temps the first half of the night. However, low level warm
advection will slow the overnight fall of temps, as minimums on
average will make it down to the upper 30s or lower 40s, except
closer to 50F on the barrier islands. Skies will begin the night
clear, but some jet stream cirrus will arrive overnight, having
little to no effect on temps.
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
Monday and Monday night: West-southwest flow will
prevail in the pattern aloft as the forecast area sits north of a
flat mid/upper level ridge situated across the Gulf of Mexico and
the Caribbean. Models continue to show some embedded shortwave
energy moving through, mainly in the Monday evening/night time
frame. As this occurs, an area of low level convergence and
increased moisture is progged to approach the region. Overall, the
trend in model guidance is toward a drier solution and keeps the
bulk of the rainfall along or just off the coast. As such, the
forecast trend continues to be lower PoP`s for land areas and just
mid range chance PoP`s for the coastal waters. We should see plenty
of sunshine early on Monday, and a nice rebound in temperatures is
anticipated. Forecast highs are in the mid to upper 70s away from
the immediate coast. Overnight, any rainfall that occurs should be a
relatively quick shot and by the end of the period will be confined
to far eastern Charleston County and the adjacent coastal waters.
Thanks to onshore flow and increased cloud cover Monday night should
be quite mild with lows only falling into the upper 50s and low 60s.
Tuesday through Wednesday: The main story through mid week will be
the expected warm temperatures. The aforementioned ridge to the
south will spread a bit further north and the low level flow will
become more southwesterly. Tuesday highs are forecast to be around
80 for southeast South Carolina and into the low 80s for southeast
Georgia. Wednesday is progged to be even a bit warmer, with low to
mid 80s becoming widespread. Models do produce some precipitation
each afternoon in some apparent diurnal convection, but a perusal of
soundings only reveals CAPE values in the 300-500 J/kg range. There
is also some capping to overcome, so nothing more than a 20 percent
chance is warranted. Also of note, conditions should be quite breezy
Wednesday afternoon with frequent gusts into the 25-30 mph range.
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Models are in decent agreement that a cold front will approach and
cross the forecast area late Wednesday night into early Thursday.
Showers and maybe a few rumbles of thunder possible with the front.
High pressure will return in its wake and remain the dominant
feature through Saturday. Temperatures will be on a slight cooling
trend through the period.
.AVIATION /20Z SUNDAY THROUGH FRIDAY/...
Extended Aviation Outlook: Flight restrictions possible in early
morning fog/stratus Tuesday and Wednesday. A cold front will move
through early Thursday with brief restrictions possible in
Tonight: High pressure will expand over the western Atlantic,
with it`s associated ridge axis to align itself to the north of
the maritime area. East winds will dominate, generally at or
below 15 kt.
Monday through Friday: High pressure will slip off the coast on
Monday and the prevailing flow will become south and southwesterly
through mid week. Wind speeds will primarily be in the 10-15 knot
range, but look to increase into the 15-20 knot range on Wednesday.
A cold front will then move through on Thursday, with northwest flow
taking hold into Friday. Conditions should stay below Small Craft
Advisory thresholds, though it could be close on Wednesday.
Sea fog: Warm southerly flow moving over the cooler shelf waters may
result in patchy sea fog developing late Tuesday into Wednesday.