Scientific Forecaster Discussion
Area forecast discussion...updated
National Weather Service Columbia SC
1114 am EST Friday Nov 27 2015
a pressure ridge will remain in the forecast area through Sunday.
A slowly approaching frontal system will remain northwest of the
area through Sunday. Above normal temperatures will occur
through the weekend.
Near term /through tonight/...
visible imagery this morning shows clear skies across the region
with only some eroding thin cirrus spilling over the top of the
upper ridge axis in North Carolina. Temperatures have warmed very
quickly under the full sun with temperatures already in the upper 60s.
Expect mostly sunny skies to prevail through the day with near
full sun and no chance of rain as surface high pressure remains in
place beneath the upper ridge axis. Thickness scheme and 850mb
temperatures just under +10c support well above normal temperatures
again today in the low to middle 70s.
The models show the upper ridging flattening tonight and expect
increased high cloudiness. The surface ridging should continue.
Fog may occur late but it may be limited by upper cloudiness
reducing net radiational cooling. Still...expect areas of fog as
indicated by the NAM and GFS MOS. The temperature guidance was
Short term /Saturday through Sunday/...
the models continue to display surface ridging in the forecast
area with the bulk of the moisture associated with the frontal
zone remaining northwest of the forecast area. The above normal
temperatures will continue south of the front. Leaned toward the
warmer high temperature guidance Saturday. Sunday should be a
little cooler because of more cloudiness associated with the
nearing front and considerable southern stream upper-level
Long term /Sunday night through Thursday/...
the GFS and European model (ecmwf) display the deeper moisture remaining northwest
of the forecast area early in the medium-range period...but an
onshore slow and weak isentropic lift plus a series of upper-level
shortwave troughs supports possible showers. The models indicate
deeper moisture Wednesday along a cold front. A wave may develop
along the front supporting rain Thursday. The GFS and European model (ecmwf) MOS
have probability of precipitation 20 to 50 percent during period. The MOS has above normal
temperatures lowering to about normal Thursday.
Aviation /16z Friday through Tuesday/...
surface high pressure continues to ridge into the Carolinas from
off the middle Atlantic coast with a dry airmass in place providing
no precipitation through the forecast period. Continued
northeasterly flow today less than 10 knots with maybe just a few
high clouds passing overhead.
Latest MOS guidance hinting at MVFR/IFR restrictions developing
tonight at all taf sites especially after 06z Saturday.
However...as was the case yesterday...not confident in the MOS
forecast of fog restrictions overnight as hi-res models continue
to not show anything and have been Superior to the MOS for the
past few days.
Extended aviation outlook...continued onshore flow will continue
to increase low level moisture. This will increase the chance for
ceiling/visibility restrictions during the early morning hours late weekend
into early next week.