Area Forecast Discussion
Issued by NWS Columbia, SC
FXUS62 KCAE 271505
Area Forecast Discussion
National Weather Service Columbia SC
1005 AM EST Mon Feb 27 2017
High pressure offshore will result in onshore flow today.
A weak upper level disturbance will move across the region
tonight and may trigger a few showers. Weak instability and a
warm front near the region Tuesday and Wednesday may result in a
few showers mainly in the afternoon. A cold front will cross
the region Wednesday night bringing a higher chance for showers
and thunderstorms. Much above normal temperatures expected
Tuesday and Wednesday. Cooler than normal late in the week but
.NEAR TERM /THROUGH TONIGHT/...
High pressure centered off the Carolina coast will result in
weak onshore flow today. Moisture increase appears marginal and
air mass will remain mainly dry in the low levels. Weak short
waves in the lower Mississippi Valley will move across the area
this afternoon and overnight. Stronger dynamics north of the
area. Expect an increase in mid and high level clouds through
the day and a few showers developing during the overnight.
Large spread in the pop guidance overnight. The strongest
isentropic lift appears to be across the SC Piedmont...although
precipitable water lacking. Expect widely scattered showers
through the overnight. With warm advection through the day
temperatures should be about 10 degrees warmer than yesterday.
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
Should be an increase in low-level moisture as a warm front
moves north of the area. With air mass quite warm...it should be
at least weakly unstable. Forcing for convection though appears
lacking. Can`t rule out isolated mainly afternoon convection
both days with focus mainly northwest of the region in the
Carolina Mountains. Temperatures both days well above normal
with near record values Wednesday in the low to mid 80s.
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Deep upper trough developing over the Eastern CONUS will drive a
cold front through the region Wednesday night. Models appear
faster with frontal passage...near central SC after Midnight
and east of the region Thursday morning. POP guidance has been
consistently high. Expect showers and thunderstorms during the
overnight. Overall instability not strong but deep layer shear
very strong. Depending on the degree of instability...strong to
severe thunderstorms are possible. The Latest SPC outlook has
most of the area in a slight risk associated with a squall
line/QLCS. Noticed 0-3km helicity strong across the north
Midlands. Timing is a limiting factor although organized
convection could develop late in the day/early evening
Wednesday. Canadian high pressure will build into the Eastern
U.S. behind this system Thursday afternoon into next weekend.
Temperatures will be near or below normal through most of the
period with fair weather
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
VFR conditions to dominate the period...with restrictions likely
High pressure will slide away from the area today with SE winds
around 5 knots pushing low level moisture into the area. Dry
mid-levels currently over the region will prevent showers
through the day. Tonight, a series of weak upper level
shortwaves will move into the region. This in combination with
increasing moisture brings a chance of scattered showers.
Isentropic lift and moisture advection is strongest across the
southern forecast area from 03Z to 09Z. Kept VCSH at AGS, DNL,
and OGB where conditions are more favorable for showers.
Elsewhere confidence is too low to include in TAFs.
Increasing low level moisture in SE flow will likely produce
fog and low ceilings over the area. Expect at least MVFR
ceilings and visibilities early tomorrow morning. Confidence is
highest at AGS where moist SE flow up the Savanna River Valley
is historically likely to produce restrictions.
EXTENDED AVIATION OUTLOOK...Periods of MVFR/IFR restrictions
Tuesday through Thursday as moisture returns to the region.