FXUS62 KCAE 180814
Area Forecast Discussion
National Weather Service Columbia SC
314 AM EST Mon Dec 18 2017
High pressure will be situated off the Southeast Coast today
with a stalled front near the area promoting a slight chance of
rain. Additional rain chances throughout the week expected with
a weak front across the area.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Early this morning...Regional radar as of 07Z shows only a few
isolated returns mainly in the CSRA. Precipitable water values
are highest in the CSRA, so continued with slight chance pops
there through daybreak but otherwise mainly dry conditions.
Widespread and increasing clouds should limit radiational
cooling this morning, so expecting much warmer min temperatures
than Sunday morning with lows in the mid 40s to low 50s.
Today...Zonal flow aloft will continue across the region today
with a subtropical high over the Caribbean. Surface high
pressure will be offshore promoting southwesterly low level
flow. A stalled boundary will be along the southern portion of
the area. Models show a tight moisture gradient from north to
south with PWATS around 0.8 inches in the northern portion of
the area and around 1.5 inches south. Have lowered pops a bit
to indicate slight chance pops south closer to the deepest
moisture and a dry forecast north. Many of the high resolution
models show only isolated coverage south. Above normal
temperatures are forecast today despite persistent cloud cover,
in the lower to middle 60s.
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
Weak upper ridging over the area through the night, with a weak
surface boundary off to the south of the cwa. Not much in the
way of any upper energy moving through, and have generally gone
with a dry forecast tonight and into Tuesday as the region will
be between upper systems. By Tuesday evening and into Wednesday,
a stronger area of low pressure aloft will be moving eastward
from the Gulf Coast states along the current surface front
across the region. Rain chances will be on the increase Tuesday
night, becoming categorical by Wednesday as the surface low
moves into the area. The low moves east Wednesday night and
drier air will move in behind the exiting low. Thursday into
Thursday night will be dry. Temperatures through the period
will be above normal Tuesday and Wednesday. A surface wedge
flow out of the northeast will setup over the region on Thursday,
keeping temperatures that day only in the low to mid 50s.
.LONG TERM /FRIDAY THROUGH SUNDAY/...
High pressure aloft will be across the area into Friday with
dry weather expected. Another strong cold front is forecast to
move towards the region over the weekend ahead of a deepening
upper trough over the middle of the country. The surface front
may become parallel to the upper flow over the Southeastern US,
stalling out somewhere near the region early next week.
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
Restrictions expected to develop early this morning and continue
for most of the 24-hr TAF period.
High pressure will remain offshore today with a stalled
boundary near the area. Clouds have thickened and lowered over
the past couple of hours, although all terminals still have VFR
ceilings at the moment. Most of the shower activity has
dissipated early this morning, but with increased moisture in
the southern portion of the area today, there will a slight
chance of showers through this evening at the TAF sites. The
chance is too low to include in current issuance. Model guidance
indicates ceilings lowering towards daybreak. Fog threat
this morning remains low given a 25 to 30 knot low level jet,
so have not included mention. Surface winds through the period
will be southwesterly at 7 knots or less.
EXTENDED AVIATION OUTLOOK...Boundary will remain stalled across
the region with rain and associated restrictions at times
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