Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Columbia SC
320 am EDT Sat may 27 2017
generally fair and warm today, with a slight chance of late
day/evening thunderstorms northern areas. A frontal boundary
will provide a slight chance of thunderstorms Sunday afternoon.
A front will slowly move through into the region Monday and
stall, providing a chance of showers and thunderstorms.
Near term /through tonight/...
upper high over the Gulf of Mexico, with upper trough over the
central Continental U.S.. upper energy will shift east into the Tennessee
Valley/srn Apps/mid Atlantic. Most of our forecast area will be dry and capped,
but better moisture to the north with the upper energy and surface
trough expected to lead to thunderstorm activity developing and
shifting east across Tennessee/north Georgia/west NC. Some high resolution model
guidance suggests some of this activity could hold together into
our north/NE forecast area late today/this evening before dissipating. Will
indicate slight chance pops for tha area.
Storm Prediction Center day one outlook has the north forecast area in a marginal risk of severe.
Moderate instability expected this afternoon with
surface temperatures in the lower 90s and strong shear.
Forecast soundings show plenty of dry air at mid levels along
with an inverted-v in lower levels. Forecast soundings also
indicate a very strong capping inversion with 700mb temperatures
over +10c which is a strong limiting factor. Convective temps
around 100 degrees so do not expect initiation to occur in our
area. Severe threat could be during the late afternoon and
evening hours from upstream convection moving into the area with
corfidi vectors from the west/northwest. Damaging wind would be
primary threat with dcape just under 1000 j/kg and fairly
Short term /Sunday through Monday night/...
upper high to shift east into the East Gulf of Mexico/FL, with upper
trough to our north. Upper impulses and surface waves to ride by
mainly just to our north, with surface front approaching from the
north and surface high axis remaining to our south, Sunday. This,
along with increasing moisture, to provide slight chance to chance
pops Sunday aftn/eve, generally appearing to favor northern areas.
Surface front to move into our region Monday, providing chance
pops. Considerable instability and deep layer shear will provide
a severe threat. Storm Prediction Center has region outlooked in a slight risk day 3.
Long term /Tuesday through Friday/...
models indicate weak upper troughiness to shift into the southeast Continental U.S..
surface front appears will stall near our region, with sufficient
atmospheric remaining in place, providing continued mainly
diurnal slight chance to chance probability of precipitation.
Aviation /07z Saturday through Wednesday/...
high confidence in VFR conditions throughout the 24-hr taf
Surface high pressure centered to the south continues to provide
dry weather over the region through today. Satellite imagery
showing some high clouds advecting over the forecast area but
forecast soundings indicate a very dry atmospheric column so do
not expect to see any lower clouds through the forecast period.
The atmosphere becomes moderately unstable this afternoon but
the lack of deep moisture and a significant capping inversion
will prevent convection from impacting the terminals.
Fog is not expected to develop this morning due to a 20-25 knot
low level jet. Surface winds will be light and variable through
the predawn hours and will pick up after daybreak to around 10
to 15 knots gusting to around 20 knots. Gusts will subside
Extended aviation outlook...a cold front will approach Sunday
and stall in the region through early next week. The front will
help support scattered thunderstorms and associated
recent rains have prompted river flood warnings and advisories
for a few of our forecast points. Please consult our web Page
for the latest more detailed information.