Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Columbia SC
700 PM EDT sun Aug 25 2019
a front will be stalled just south of the forecast area through
Monday. The front will become a warm front and may lift northward
and into the area Tuesday and linger Wednesday, bringing a
chance of rain. Low pressure tracking northeastward off the
coast will have little impact on our weather. An approaching
cold front will move into the area by Thursday.
Near term /through 6 am Monday/...
polar air mass (for august) firmly in place this evening as a
Spring-like wedge is in place at the low levels. Surface winds
out of the northeast and north should persist all night,
continuing to feed cooler than normal air into the midlands and
csra. Trapped low level moisture will provide mostly cloudy
skies overnight, and some cirroform clouds will be moving in
from the west in addition.
Short term /Monday through Tuesday night/...
cloudy and somewhat cool conditions will persist on Monday with
surface high pressure wedging into the forecast area from the
north with the front stalled south of the area. The Wedge
pattern and weak lift support little instability so do not
expect thunderstorms, but showers are expected to move in from
the south late in the day and overnight. The high temperature
guidance is likely too high because of The Wedge pattern Monday.
Highs will likely be in the upper 70s to low 80s.
Thunderstorm chances will be better on Tuesday as the stalled
front returns in the form of a warm front. A dampening mid-
level shortwave trough is also forecast to move into the
region. However, cloudiness should help limit instability and
shear will be weak at only around 20 to 25 kts, so there is a
diminished chance of severe thunderstorms. Temperatures should
warm up into the mid 80s.
Long term /Wednesday through Sunday/...
upper level troughing will be over the eastern U.S. Through the
period, bringing unsettled weather. A cold front will move
through the region Wednesday, and then stall near the coast for
Thursday and Friday. The closeness of the front supports keeping
a chance of showers and thunderstorms in the forecast. Lee
troughing and onshore flow will bring diurnal convection on
Saturday, and another front is expected to move in on Sunday.
Temperatures will rebound to near normal with highs in the upper
80s to low 90s and lows in the upper 60s to low 70s.
Aviation /00z Monday through Friday/...
surface ridge extending southwest across the region from the mid
Atlantic region. Ceilings have improved across the area with all
terminals currently VFR with strato-cumulus. Satellite
indicating lower ceilings (mvfr) across northeast SC moving
The main issue...models do not appear to handle trapped low-
level moisture expected overnight and indicate little in the way
of restrictions. However, will continue forecast of lowering
ceilings back to MVFR overnight into early/mid Monday morning as
low level moisture should become trapped below inversion...but
delay onset a few more hours. Northeast winds around 10 knots
this evening will diminish to around 5 knots overnight. Fog not
expected overnight with mixing in the boundary layer. Expect
ceilings to improve to VFR by mid morning with deeper moisture
to the west.
Extended aviation outlook...potential for IFR or MVFR
conditions mainly late night and early morning stratus/fog with
possible showers/thunderstorms Tuesday through mid week.