Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
939 am EST Monday Jan 26 2015
fast moving low pressure system will cross the region today with
isolated light showers and breezy conditions. Dry high pressure
will build into the area Wednesday with a reinforcing cold front
crossing the area Thursday night.
Near term /through tonight/...
large amplified upper trough over the region at middle-morning will
be swinging east this afternoon. Water vapor indicates several
short waves upstream across the upper and middle Mississippi River
valley to cross our area this afternoon and evening. The coldest
air aloft currently crossing the region.
At the surface clipper system centered over western NC with a
secondary low off the Carolina coast. Moisture appears limited
for most of the day and lift weak as 700 mb-500 mb DPVA limited. Kept probability of precipitation
in the slight chance for the northern midlands and Pee Dee region
and dry farther south. Considerable clouds to return for the
midday and afternoon hours due to steepening low to middle level
lapse rates and shallow low-level moisture.
Temperatures will range through the 50s with the cooler readings
north and west and upper 50s south and east. Gusty winds expected
this afternoon...with strongest winds in the csra associated
with 850mb jetmax. Lake waters relatively cool...so strongest
winds near-shore...gusts to 25 kts to 30 kts possible. Highest
confidence for strongest winds in the csra...Clarks Hill/Thurmond
Lake. Lake Wind Advisory noon to 10 PM as cold air advection
increases behind cold front.
Clearing skies and cold advection tonight as upper negatively
tilted upper trough will be off the coast. Low temperatures will
be in the lower to middle 30s with diminishing winds.
Short term /Tuesday through Wednesday night/...
the large upper trough continues over the eastern Continental U.S. Tuesday
with its deep surface and upper low center moving northward from
the middle-Atlantic region to coastal southern New England. Periods
of clouds expected Tuesday as short waves rotate around base of
upper trough. Moisture overall appears quite limited...so dry
forecast. Temperatures below normal Tuesday due to cold advection.
The upper trough moves off the coast Tuesday night with heights
rising for Wednesday. Cool high pressure builds across the region
Wednesday and Wednesday night. Very dry air mass overspreading the
region with dew points in the teens. Will keep the forecast dry
with highs in the upper 40s to middle 50s and lows Wednesday night
from the middle 20s to around 30.
Long term /Thursday through Sunday/...
models continue in good agreement Thursday then with increasing
differences by Friday.
Model differences begin Thursday night as the GFS tracks low
pressure through the southern Great Lakes and through the Ohio
Valley Thursday night while the European model (ecmwf) keeps the low in the
northern Great Lakes. Both models bring a cold front through the
forecast area Thursday night with the GFS being stronger and
faster with the front due to the low center much further south
than the European model (ecmwf).
Cold high pressure expected to build in Friday and Saturday. The
European model (ecmwf) brings another cold front through the area Saturday night
while the GFS generates low pressure off the southeast coast.
Temperatures near normal Thursday...then below normal for next
weekend. GFS ensemble probability of precipitation through period low. Not confident
enough to indicate precipitation with the frontal passage.
Aviation /15z Monday through Friday/...
VFR conditions expected through the taf period.
Low pressure over western NC and off the Carolina coast will
consolidate off shore and lift northeast away from the taf sites
this afternoon and tonight.
Clouds continue moving toward the area with low and middle clouds
moving into the csra at this time. Expect ceiling to remain VFR.
Though...some clouds around 2 kft will be possible. The chance
for showers is too low to include in tafs.
Westerly winds to increase through midday...15 knots with gusts
to 25 knots...then slowly subside to around 8 knots with gusts to
14 knots by 27/09z.
Extended aviation outlook...breezy conditions continuing through
SC...lake Wind Advisory until 10 PM EST this evening for scz015-016-
Georgia...Lake Wind Advisory until 10 PM EST this evening for gaz040-