Area forecast discussion
National Weather Service Columbia SC
229 PM EDT Wednesday may 22 2013
Synopsis...
high pressure off the southeast coast will circulate a moist
southerly flow into the forecast area ahead of a slow moving cold
front through Thursday. The cold front will move through the area
Thursday night. The dry air mass behind the front will dominate
during the weekend.
&&
Near term /through tonight/...
high pressure off the Atlantic coast continues to push moisture
into the forecast area with satellite imagery showing cumulus
developing across the region. Cae WSR-88D returns shows showers
developing through the csra as well as activity along the
intensifying sea breeze. Expect the showers to increase in
coverage over the next couple of hours...with some becoming
thunderstorms. Severe threat remains low with isolated hail and
gusty winds the main concerns. Convection will diminish with loss
of heating this evening and cease overnight. Skies will remain
mostly cloudy through the night as the front approaches from the
west with chances of showers increasing from west to east during
the pre-dawn hours. Overnight lows will generally be in the middle
60s.
&&
Short term /Thursday through Thursday night/...
middle and upper level trough crossing the eastern Continental U.S. During the
short term. The airmass will be unstable with a pre-frontal trough
over the midlands. Low level moisture lingers with precipitable
water ranging from 1.00 t0 1.75 inches. The threat of convection
will continue with the highest chance across the midlands. Will
range probability of precipitation from near 30 percent csra to 60 percent northeast on
Thursday. Although the GFS is slightly faster...models indicate the
cold front crossing the area Thursday night with the chance of
convection ending.
The temperature guidance was close with highs in the middle/upper 80s
and lows in the lower 60s.
&&
Long term /Friday through Wednesday/...
the dry air mass behind the cold front should dominate during the
weekend. The GFS and European model (ecmwf) indicated a warm front developing
Monday with much of the moisture north of the forecast area Monday
through Wednesday. GFS ensemble increase probability of precipitation slightly through the
middle of next week. Will keep the forecast dry given increasing
h500 heights as the upper ridge builds.
Expect below normal temperatures during the weekend and near normal
during the rest of the medium range period.
&&
Aviation /18z Wednesday through Monday/...
mainly VFR conditions through the taf period.
Satellite imagery shows the stratus associated with morning fog
has burned off with cumulus developing as temperatures rising into
the lower 80s. WSR-88D imagery shows showers to the southwest of
ags/dnl with additional showers along the developing sea breeze
toward the coast. Expect the showers to increase in coverage over
the next couple of hours with some intensifying into
thunderstorms. As such have included a tempo for showers in the
ags/dnl area while confidence in other locations remains too low
at this time. Overnight fog development threat also remains low as the
cold front approaches from the west preventing a strong inversion
from developing. Front will cross the area Thursday morning and
with the front weakening as it moves into the area confidence in
rain with the front is low.
Extended aviation outlook...
increasing confidence in strong and gusty winds Friday late
morning into Friday evening.
&&
Cae watches/warnings/advisories...
SC...none.
Georgia...none.
&&
$$
