Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
1050 PM EDT Tuesday Jul 29 2014
a cold front has crossed the region and cooler and drier air will
enter our region through Wednesday. Moisture will return to the
region late in the week and into the weekend...allowing for a
chance of showers through the weekend.
Near term /until 6 am Wednesday morning/...
few clouds remain across the area and have combined with light
winds to produce excellent radiational cooling conditions.
Temperatures have been dropping steadily through the 70s with many
locations already in the lower 70s. Expect this trend to slow over
the next couple of hours with middle 60s at most locations by
Short term /6 am Wednesday morning through Thursday night/...
an upper trough will remain anchored over the Great Lakes region
on Wednesday with westerly flow aloft. This will promote unseasonably
cool and dry weather across the southeastern states. Surface winds
will veer to more of an easterly direction by late Wednesday. The
upper trough will slowly retrograde westward with upper flow
becoming more southwesterly and deeper moisture returning to the
forecast area on Thursday. Kept Wednesday dry but continued to
indicate a slight chance of afternoon/evening convection on
Thursday due to the combination of increased moisture and diurnal
heating. Temperatures will be below climatology both Wednesday and
Thursday with highs in the upper 80s and overnight lows in the
upper 60s to near 70. Guidance and local numbers were close.
Long term /Friday through Tuesday/...
the long term period looks unsettled and wet with an upper trough
over the upper Great Lakes region promoting deep southerly flow
across the area through the weekend with weak onshore flow from the
Atlantic. The upper flow becomes more zonal by early next week.
Models show insentropic lift increasing on Friday with
precipitable water values rising to over 1.5 inches. Precipitable
water values remain elevated through the weekend at just over 2.0
inches on Sunday. Temperatures will continue to be below normal
through much of the extended with highs in the middle to upper 80s
and overnight lows in the upper 60s to lower 70s.
Aviation /03z Wednesday through Sunday/...
VFR conditions expected through the 24 hour taf forecast period.
Continued dry air in place through the atmospheric column will
provide VFR conditions through the period. Scattered clouds around
8000-10000 feet can be expected through the forecast period as the
region remains under the influence of cyclonic flow within the East
Coast trough. Winds have subsided and will be light and variable
around 5 knots or less through Wednesday afternoon.
Extended aviation outlook...MVFR or lower conditions are possible
Thursday nt/Friday as moisture returns due to an easterly flow off the