Area Forecast Discussion
Issued by NWS Columbia, SC
FXUS62 KCAE 282227
Area Forecast Discussion
National Weather Service Columbia SC
627 PM EDT Tue Mar 28 2017
A cold front will move through the area tonight and stall near
the CSRA. The pressure ridge will build southwest across the
Carolinas from the north then move off the east coast Thursday.
Moisture will return Thursday with a chance of showers...
especially in the CSRA. A warm front will move through the area
early Friday followed by a cold front late. Numerous showers and
thunderstorms are expected Friday. It will be slightly cooler
Thursday and Friday with unsettled conditions but warmer and
drier over the weekend.
.NEAR TERM /THROUGH WEDNESDAY/...
The cold front will cross our area from north to south tonight.
Much of the moisture has already shifted east of the area ahead
of the front and any showers or thunderstorms associated with
convergence near the front this evening should be isolated as
indicated by the HRRR. Winds may remain around 5 mph through the
night behind the front. Kept overnight lows near the consensus...in
the middle to upper 50s.
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
Ridge aloft and at the surface Wednesday and expect strong
subsidence. Although low-level flow from the north...air mass
appears to moderate quickly behind the front and along with
subsidence expect mild afternoon temperatures in the low 80s
with little in the way of clouds. Clouds expected to increase
late Wednesday night across the Piedmont/CSRA then spread into
the Midlands as weak isentropic lift and low-level moisture
flux increases. Moisture appears too shallow for showers until
after 12z Thursday. Upper-level ridge off the coast Thursday
with deep low in the Midwest moving east with southwest flow
aloft developing. Previous models runs suggested cold air
damming Thursday with surface ridge off the New England and Mid
Atlantic coast extending southwest into the Carolinas. That`s
still the case but appears to be very weak with dry air in the
east Midlands...more east-southeast low-level flow and focus
for isentropic lift and deeper moisture in the Upstate SC and
portion of the CSRA. It`s possible it may be cooler during the
afternoon in the CSRA than Pee Dee or east Midlands due to
higher probability of showers in that region. Models suggest at
least weak instability near the stalled front in the CSRA so
mentioned thunder there. Stayed close to current temperature
forecast which is near or slightly below the consensus Mos
Guidance given pattern. Warm front may begin to lift north
during the evening and overnight Thursday with increasing deep-
layer shear. Potential for strong thunderstorms late at night
especially toward dawn Friday. Deep lift associated with
approaching upper-level low/strong deep-layer shear at least
moderate instability and approaching cold front/occlusion during
the afternoon supports high probability of showers and
thunderstorms. SPC has region in a risk of severe thunderstorms
.LONG TERM /FRIDAY THROUGH TUESDAY/...
Dry conditions over the weekend as ridge builds over the area.
Another deep low in the central Plains will be moving east-
northeast early next week and bring another chance of showers
and thunderstorms Monday and possibly Tuesday although 12z
models appear a little faster. Temperatures remain above normal.
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
Mainly VFR conditions expected throughout the 24-hr TAF period.
Isolated/scattered convection expected across the TAF sites this
afternoon. A weak upper level disturbance will cross the the area
from late afternoon through early evening. The airmass is forecast
to become weakly unstable as a cold front approaches from the north.
The cold front will push south of the CSRA by 09Z. Drier air will
move into the area behind the front with clearing skies and the
threat of showers/storms diminishing.
Westerly winds 10 to 15 knots with gusts around 20 knots this
afternoon will diminish with sunset...becoming light northerly
overnight as the frontal boundary crosses the area from the north.
The chance for vsby restrictions are low given drier air mass moving
into the area and a 20 knot low level jet overnight.
EXTENDED AVIATION OUTLOOK...Restrictions possible in showers and
thunderstorms Thursday through Friday night as an cold front crosses