Area Forecast Discussion
Issued by NWS Charleston, SC
FXUS62 KCHS 281418
Area Forecast Discussion
National Weather Service Charleston SC
1018 AM EDT Fri Oct 28 2016
High pressure will prevail through the weekend. A backdoor cold front
will move through the Carolinas on Monday, followed by high pressure
into the middle of the upcoming week.
.NEAR TERM /THROUGH TONIGHT/...
Today: An upper trough axis associated with a low pressure system
over the Northeast will shift off the Eastern seaboard this
afternoon, nudging an upper-lvl jet off the Southeast Coast. At the
sfc, a weak cold front extending south from the departing low
pressure system will have minimal impact to the region, with only
a slight wind shift from west to north over South Carolina. Dry
weather is expected throughout the day while mid-lvl ridging
starts to expand over the Southeast behind the departing trough. A
full sun during mid to late afternoon hours will help temps warm
into the lower 80s or possibly mid 80s for many locations aways
from the coast.
Tonight: Surface high pressure will build over the region and a
tranquil night is in store. Clear skies and calm winds will result
in lows from the mid/upper 50s inland to the lower 60s on the coast.
There may be patchy fog in a few spots, but no mentions have been
introduced to the forecast at this point.
.SHORT TERM /SATURDAY THROUGH MONDAY/...
Deep layer ridging will reside over the area Saturday and Saturday
night, keeping dry and warm conditions in place. The upper level
pattern will flatten out by Sunday and a very low amplitude
shortwave trough will move across the Carolinas Sunday night and
Monday morning. With persistent subsidence in the mid-levels though
the period, no rainfall is anticipated despite the transition in the
upper level pattern.
At the surface, high pressure will smother the Southeast through the
weekend before weakening and sliding off the coast Sunday Night.
Broad high pressure sliding over the St. Lawrence River Valley will
then ridge down the east coast, nudging a backdoor cold front into
the Carolinas on Monday. It is uncertain exactly when the front will
reach our area, but whenever it does it will be weak and bring only
a subtle and gradual airmass change for the middle of the week.
Temps through the period will be well above normal with highs Sunday
and Monday challenging daily records.
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
Strong, deep layer ridging settles overhead once again for the
middle of next week, keeping a rain-free forecast in place for all
land areas. Surface high pressure over eastern Canada slides south
and elongates meridonally over the southern Mid-Atlantic and North
Carolina through the day Tuesday. Anomalously strong subsidence will
keep temps well above normal through the middle of the week, though
high pressure centered just north of the area will prompt light
onshore flow that should moderate temps to below record levels. Weak
ridging offshore could prompt a few showers over the waters,
especially at night middle-to-late week, but not currently expecting
anything to reach the beaches.
Next significant pattern change may come late next week as upper
level troughing digs across the eastern United States.
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
VFR conditions are expected at both CHS and SAV terminals through
06Z/29. The potential for fog could increase late tonight as clear
skies and light northeast winds prevail. However, confidence is too
low to include in the latest TAF issuance.
Extended Aviation Outlook: VFR conditions expected to prevail
through this weekend with low probabilities for late night or early
morning restrictions in patchy fog, especially Monday night/Tuesday
Today and Tonight: A weak trough axis will shift offshore, supporting
a light north/northeast flow at or below 10 kt over all coastal
waters. A seabreeze will help turn the flow more onshore this
afternoon, but conditions will remain well below Small Craft
Advisory levels throughout the day. Tonight, high pressure will
build from the north, causing northeast winds to increase over the
Georgia waters late. However, winds should be no higher than 15
kt. Seas will range between 2-3 ft in nearshore waters and 3-5 ft
in offshore Georgia waters.
Saturday through Wednesday: High pressure will keep winds mainly 10
kt or less through the weekend with small background swell in the 2-
4 ft range in the water. High pressure building down the coast
Monday night and Tuesday will tighten the gradient over the waters,
with winds as high as 15 to 20 kt possible mainly for the offshore
waters, and a modest increase in local wind swell, with seas as high
as 5 ft possible for the offshore waters and 2-4 ft for the
nearshore waters through mid-week.
An approachable record high temperature could occur at today at KCHS
where the existing record of 86 degrees was set in 1963 and previous