Scientific Forecaster Discussion
fxus62 kcae 171743
Area forecast discussion
National Weather Service Columbia SC
1243 PM EST Tue Jan 17 2017
a weak cold front will move through the region on Wednesday
with widely scattered showers. As low pressure moves northeast
from the lower Mississippi Valley late Thursday, showers will
spread into the region. Although cool temperatures possible
Thursday, temperatures through the week should be above normal
at times. Unsettled weather continues into the weekend with rain
Near term /through tonight/...
this afternoon: weak front will once again push northward
through the area, bringing thinning clouds, sunshine, southerly
winds, and some warmer temperatures.
Tonight: another surface front will be west of the region
through the night, but will be approaching the area towards
sunrise on Wednesday. Most of the night will remain dry across
the forecast area, but towards morning there may be some light
rain moving in just northwest of the cwa ahead of the
approaching front. Rain chances mainly in the isolated category,
and confined to the northern counties. With the front north of
the area overnight, and low-level moisture still remaining, can
not rule out the return of some fog. Inhibiting factor will be
stronger low-level winds and mixing through the night. Have
elected to only go with patchy fog wording. Lows will moderate
upwards to the upper 50s.
Short term /Wednesday through Thursday/...
a trough will drive a weak cold front through the area during
the day Wednesday. Although increase in precipitable water
noted, lack of surface convergence and downslope flow should
result in limited showers in the area. Forcing appears strong to
the north of the area. Will continue slight chance pops
associated with frontal passage. Temperatures warmer, due to
downslope flow and clearing in the afternoon.
Upper flow backing Thursday ahead of deepening low in the lower
Mississippi Valley. Surface ridge over the Carolinas. Moisture
appears to increase rapidly during the day, and a few showers
may develop mainly in the csra/west midlands. Weak in-situ
wedge may develop although surface winds more east-southeast in
the afternoon. Increasing clouds should result in cooler
temperatures, especially north midlands. Went below guidance for
highs in the north. Large temperature gradient possible and
Long term /Thursday night through Tuesday/...
a very active southern branch of jet stream will push two systems
into the southeast U.S. Late this week into early next week. The
first system arrives Thursday night into Friday with the second
system, possibly strong, forecast for Sunday into Monday with a
thunderstorm threat. Expect unsettled weather and for the most
part above normal temperatures during this time period.
Aviation /18z Tuesday through Sunday/...
surface wedge front has now pushed north of the taf sites. VFR
conditions expected through the afternoon and early tonight at
all sites. Winds southwest between 5 and 10 knots into tonight.
Patchy fog may once again be an issue early Wednesday morning
across the area given the latest model guidance, but not enough
confidence to mention in the tafs at this time. Models
indicating a return of restrictions late tonight and towards 12z
Wednesday. MVFR visibilities and IFR/LIFR ceilings possible by
morning at all sites. Conditions should improve back to VFR by
15z. Winds will increase out of the west/southwest during the
day Wednesday, with some gusts up to 16 knots becoming possible
ahead of the front.
Extended aviation outlook...late night/early morning fog
possible through Saturday. Showers and associated restrictions
possible Thursday through Saturday.