Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
1009 PM EST Friday Nov 27 2015
high pressure will remain over the midlands and csra through
Sunday...bringing above normal temperatures. A slow moving
frontal system will approach from the north Monday bringing a
chance of rain. Another cold front will cross the area
around the middle of next week.
Near term /until 7 am Saturday morning/...
surface high pressure will hold across the region overnight.
Upper level ridging over the southeastern states will gradually
weaken. Should continue to see thin high level clouds cross
the area in westerly flow aloft.
Mostly clear skies are forecast overnight with the main band of
moisture well to the west along a cold front across the plains.
Strong radiational cooling expected with near calm winds and
mostly clear skies allowing temperatures to fall back into the
40s. Dewpoints in the upper 40s to lower 50s should support at
least patchy fog overnight.
Short term /7 am Saturday morning through Sunday/...
upper level and surface ridging will keep precipitation and the
deeper moisture associated with the frontal system to the
northwest of the forecast area over the weekend. However the high
will begin to weaken during the short term allowing for some
increasing moisture and cloudiness with greater coverage to the
north. High temperatures may have a large spacial gradient due to
the uneven surface heating. Highs on Sunday will be 5 to 10
degrees cooler in the northern midlands than in the southern
midlands. Went slightly warmer than guidance due to the recent
cool bias but accounted for increased cloud cover.
Long term /Sunday night through Friday/...
southwesterly middle level flow returns to the forecast area (fa)
Monday and Tuesday. Increased moisture advection and isentropic
lift over the surface high may produce showers Monday afternoon
through Tuesday. However the strongest lift appears to remain in
the upstate and Pee Dee regions. The GFS indicates a series of
upper level disturbances that move over the forecast area early next week
which could enhance rainfall potential. The cold front moves east
midweek keeping a chance of rain in the forecast.
Both the European model (ecmwf) and the GFS develop a low pressure system in the
Gulf along the baroclinic zone of the cold front. The models bring
the system up the East Coast supporting a chance of rain Thursday
and Friday. Near normal temperatures expected towards the end of
Aviation /00z Saturday through Wednesday/...
surface high pressure will remain over the region with light
winds. Satellite and model guidance suggests some increase in middle
and high level cloudiness possible late tonight. Otherwise...some
slight increase in low level moisture/dewpoints along with a
decrease in surface/boundary layer winds could provide potential
for fog. Fog potential would be hampered by any increase in
cloudiness. At this time...will restrict fog mention to the fog
prone sites ags and ogb. After any early morning fog
dissipates...VFR expected Saturday.
Extended aviation outlook...ceiling restrictions possible late Sunday
night into early next week.