Scientific Forecaster Discussion
fxus62 kcae 210853
Area forecast discussion
National Weather Service Columbia SC
353 am EST Thu Feb 21 2019
a frontal system will be stalled in the region through the rest
of the week. Drying will occur behind a cold front early next
week. Another cold front could affect the area during the
middle of next week.
Near term /through tonight/...
high low-level moisture just north of The Wedge front has
resulted in areas of dense fog. Expect the dense fog will become
more widespread during the early morning hours based on
observation trends and the hrrr. We have posted a dense fog
The NAM surface-based Li pattern suggests The Wedge front will
shift northward but only reach a position near the extreme
southeast part of the forecast area late today. The front and
associated deeper moisture are forecast to hold just northwest
of the area today. The models and observation trends indicate
elevated convection with considerable lightning associated with
a mid-level shortwave trough will remain just northwest of the
forecast area today. The pattern indicates continued cloudy
and cool conditions locally with periods of drizzle or light
rain associated with weak isentropic lift. We followed the lower
temperature guidance today because of The Wedge pattern but
there is increased uncertainly mainly in the southeast section
because of the placement of The Wedge/warm front.
The models show the main front that has been just to our
northwest sinking southward tonight. There should be an
increased chance of rain because of convergence along the front
especially in the north section of the forecast area where the
models depict deeper moisture. The GFS indicated a mid-level
shortwave trough and there may be enough instability for
elevated thunderstorms mainly in the northwest section this
evening. The guidance consensus supports rain totals around one-
quarter of an inch. Followed the guidance consensus for the
Short term /Friday through Saturday/...
high pressure aloft over the Caribbean will continue to ridge
into the southeastern states. Surface high pressure will remain
along the eastern Seaboard with wedge conditions persisting
Friday through Saturday. Widespread clouds and cool temperatures
are expected. Although there will be weak dynamics over the
region, ample moisture in place and some weak isentropic ascent
will produce period of light rain and patchy drizzle.
The main issue for the short term will be temperatures with
the frontal boundary and wedge across the forecast area. As The
Wedge strengthens Friday the temperature gradient will move
southward across the csra and southeastern midlands.
High temperatures both Friday and Saturday will range from near
50 along the SC/NC border to the mid and upper 60s across the
csra and southeast midlands.
Long term /Saturday night through Wednesday/...
models are in good agreement through the long term.
A cold front west of the mountains Saturday night will sweep
through the area Sunday morning. High pressure and dry air will
build over the region Sunday afternoon through Tuesday. The area
of high pressure is forecast to move offshore Tuesday night
allowing another cold front to affect the region Wednesday.
Temperatures through the long term will be at or above normal.
Aviation /09z Thursday through Monday/...
IFR conditions are forecast through most of the 24-hour taf
period. Low-level wind shear will likely be an issue.
The Wedge front will likely remain south of the terminals
through today based on the NAM surface-based Li pattern. There
will be continued high low-level moisture with IFR conditions
likely persisting. Weak isentropic lift will help support
periods of drizzle and light rain. Thunderstorms near the main
front will likely hold just northwest of the area today.
The main front will sink farther southward tonight. Convergence
along the front will help support continued IFR conditions with
times of showers. Thunderstorms will be possible associated with
elevated instability ahead of a mid-level shortwave trough
mainly this evening, but the chance was too low to include in
the terminal forecasts at this time.
The kcae 88d and NAM indicated low-level wind shear. We
followed the NAM and included shear in the forecast through 16z.
The model indicated a little weaker low-level jet after that
time, but it is possible shear will continue to be an issue
with The Wedge front still just south of the area.
Extended aviation outlook...flight restrictions are expected at
times through early Sunday with a frontal system remaining in
the forecast area. Improving conditions may occur beginning late
Sunday as the front finally pushes east of the area.
Georgia...dense fog advisory until 11 am EST this morning for gaz040-
SC...dense fog advisory until 11 am EST this morning for scz015-016-