Area Forecast Discussion
Issued by NWS Columbia, SC
FXUS62 KCAE 060554
Area Forecast Discussion
National Weather Service Columbia SC
1254 AM EST Tue Dec 6 2016
A storm system along the Gulf Coast will move northeastward to
the Ohio valley spreading widespread rain over the forecast area
tonight into Tuesday. Dry high pressure will briefly build across
the area for Wednesday. Another cold front will cross the region
Thursday bringing much colder air for the end of the week.
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Rain will continue to move northeast across the area overnight.
The water vapor imagery indicate upper lift upstream which should
reach the forecast by early this morning. At the surface...wedge
conditions continue with depth at around 3 to 4 kt feet. The
models depict increasing isentropic lift with a strong h85 jet
developing. Forecast categorical pops. Followed the SREF mean
rainfall amounts. Expect little temperature change with the cloud
cover and rainfall. Temperatures will remain in the 50s.
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
Upper low, currently near Tex/La, will shift NE through the SE
CONUS/Mid Atlantic states through Tuesday. Satellite water vapor
imagery confirms a good tap of tropical moisture from the E PAC
ahead of the system. As upper and surface low move NE, upper lift
and isentropic lift combined with abundant atmospheric moisture
expected to provide another batch of widespread rain overspreading
our region through early Tuesday. In situ wedge will develop at
the surface in response to the rainfall, with a typical secondary
low developing near the coast. Wedge boundary will lift north some
as a warm front, due to a strong SW 50 kt low-level jet. Some
question as to how far north the wedge boundary/warm front can
get. Some possibilities that the warm front could move into our
southern FA. Associated instability and shear could provide a
severe threat across that area. Bulk of precipitation expected to
shift east of our FA by late afternoon. Behind the departing
system, drier air will move in aloft late Tuesday into Wednesday,
but low-level wedge and associated low cloudiness could be slow to
scour out Tuesday night/Wednesday, with inverted surface trough
lingering over the region.
.LONG TERM /THURSDAY THROUGH MONDAY/...
Upper trough will swing from the central CONUS to the E CONUS
Thu/Fri, ahead and south of which an upper impulse will ride across
the southern tier of states and across our region Thursday. A cold
front will move through our region Thursday. Models indicating
limited moisture with the system, with the most recent guidance
blend confining slight chance pop to the N FA. Behind the front,
cold dry polar high pressure will shift into the SE CONUS. Breezy
conditions possible Thursday and Thursday night. A lake wind
advisory may be needed. The center of the high is expected to be
overhead by Saturday morning with appearance of good radiational
cooling conditions. Long range MOS projected lows in the mid 20s.
Will undercut guidance a little as those numbers may be a little
high as they are skewed towards climatology that far out. Daily
record low for Columbia for Dec 10th is 20, and for Augusta is 16.
Latest GFS seems to be coming around more towards the EC, with
indications of a slow moving system affecting the region late
Sunday into early next week. Used guidance blend.
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Latest Southeast radar composite shows initial batch of rain
moving across much of the Carolinas and into southern GA.
Additional rainfall is developing farther southwest closer to s/w.
Expect widespread IFR conditions to develop overnight. Conditions
have already deteriorated across the CSRA and OGB. The rain will
continue through Tuesday afternoon. Some LIFR CIGS may be
possible as well during the overnight hours. Shear will be on the
increase associated with this jet with the wedge front just south
of the area. NAM still indicating a potential for LLWS from the
pre-dawn hours Tuesday morning to around 15z. There may be
isolated thunderstorms during the 10z to 18z time frame associated
with the low-level jet and cooling aloft ahead of an upper trough.
However, the chance is still too low to include in the terminal
forecasts at this time. Precipitation should be tapering off from
the west by late Tuesday afternoon.
EXTENDED AVIATION OUTLOOK...
Widespread IFR conditions may continue into Tuesday night. The
front will be east of the forecast area Tuesday night but some
lingering troughing and high low-level moisture combined with
nocturnal cooling may result in significant fog. Another cold
front may bring more showers and associated restrictions Thursday.
Breezy conditions may also be associated with the front.