Scientific Forecaster Discussion
fxus62 kcae 241854
Area forecast discussion
National Weather Service Columbia SC
254 PM EDT Mon Jul 24 2017
an upper level trough will remain over the eastern U.S.
With southerly flow keeping warm and humid conditions across the
area. This will keep thunderstorms in the forecast today with
scattered afternoon and evening showers and thunderstorms. A weak
cool front will stall near the area on Tuesday, then drop
southward on Wednesday. Somewhat drier conditions are expected
late in the work week, with a stronger cold front expected to
affect the area over the weekend with more unsettled conditions.
Near term /through tonight/...
stratus has mixed out with showers and thunderstorms already moving
through the csra which cleared out much earlier. Short wave will
move into the forecast area later this afternoon and expect coverage
of thunderstorms to expand into the midlands over the next couple of
hours. Main threat with the thunderstorms remains damaging wind
gusts...with secondary concern of locally heavy rainfall. Hydro
concerns slightly elevated from yesterday after several areas
received very heavy rainfall and will continue to monitor.
Convection will diminish late this evening...however with outflow
boundaries across the area intersecting will expect a few cells to
persist into the early morning hours. Although there will be debris
cloudiness over the area tonight with a rain cooled air mass
overnight lows will generally be in the low to mid 70s.
Short term /Tuesday through Wednesday night/...
Tuesday and Tuesday night...a long wave trough will extend down
across the region from New England, while a strong ridge of high
pressure persists over the Southern Plains. At the surface, a
nearly stationary front will linger to the north, while a weak
pre-frontal trough extends across parts of the midlands and
upper csra. Showers and thunderstorms are expected to increase
in coverage through the day, becoming greatest southeast of the
pre-frontal trough where the deepest moisture will be found.
However, convection developing along the stalled front to the
north could propagate into the area along outflow boundaries
late in the afternoon and during the evening. Steepening low
level lapse rates and mid-level dry air could support a few
strong/severe thunderstorms capable of producing isolated
damaging wind gusts. Heavy rainfall is also a potential. High
temperatures should be in the lower 90s most areas, with
nighttime lows in the lower to mid 50s.
Wednesday and Wednesday night...a cold front will drop south of
the area in the morning, with a weak wave of low pressure
tracking along it across southern Georgia during the afternoon.
Forcing for ascent provided by the front and short wave energy
aloft will be enough to produce scattered to numerous showers
and thunderstorms, mainly in the afternoon and evening.
Temperatures will be kept down some by the cloud cover, with
highs around 90 or in the lower 90s.
Long term /Thursday through Sunday/...
a slightly drier airmass is expected to advect into the area on
Thursday, as upper level ridging briefly builds in from the
west. A Lee side trough will then set up over the area on
Friday. Will only indicate a low chance of showers and
thunderstorms in the forecast for both days. A deep trough will
develop over the weekend, as a stronger cold front crosses the
area. Showers and thunderstorms appear likely on Saturday. Will
also need to monitor for the potential for severe weather with
the cold front Saturday. Unsettled conditions are expected to
linger into early next week. Temperatures will be near normal
late in the work week, then slightly below normal over the
weekend and into early next week.
Aviation /19z Monday through Saturday/...
convection expected through 03z...then VFR conditions for the
remainder of the period.
Stratus has eroded over the terminals with thunderstorms moving
through ags/dnl which cleared out a couple hours ago. Expect
thunderstorms to expand into cae/cub/ogb over the next couple of
hours and continue into early tonight. Concern with
thunderstorms remains damaging winds and locally heavy
rainfall. Convection will dissipate overnight with mixing
continuing through daybreak so have no mention of stratus/fog
during the early morning hours. Cumulus will again develop
during the late morning and into the afternoon hours as another
round of convection is expected Tuesday afternoon.
Extended aviation outlook...increasing confidence in
restrictions in mainly afternoon/evening thunderstorms...along
with late night/early morning fog and stratus...each day through
Wednesday. Potential for showers/thunderstorms will decrease
Thursday and Friday. Convection associated with a cold front
Saturday could bring increased chances of flight restrictions.