Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 270553

Area Forecast Discussion
National Weather Service Columbia SC
153 AM EDT Thu Oct 27 2016

Fair and warm conditions will be the general rule through early
to mid next week. A weak front, with limited moisture, will
traverse the forecast area late today/tonight, with fair and
warming conditions expected Friday into the weekend. A weak dry
front moving through late Sunday/early Monday will reinforce
continued dry conditions early to mid next week.


Upper ridge over the W CONUS with upper trough central/E CONUS.
Upper disturbance currently to our west, will weaken and shift
east today/tonight. Surface high pressure over the region
currently, will weaken and pull east ahead of the approaching weak
surface boundary. Very dry airmass in place ahead of front with
PWATs around 0.6 inches. PWATs increase to a peak near 1.25 inches
just ahead of the front this evening. Projected instability is
weak to moderate with weak shear and most model guidance keeps
most of the convection north of the forecast area although the
northern Midlands could see a few showers or isolated
thunderstorms this afternoon/evening. Severe threat looks limited
given marginal instability/shear and westerly 850mb jet at around
20 knots.


Behind the weak front/trough, surface high pressure will shift
into the region late Friday into the weekend. Upper trough over
the E CONUS will lift to the north some, with upper ridge center
shifting east along the Gulf coast, providing a continued dry WNW
to NW flow aloft for our area. With building upper heights over
our FA and main nearly zonal upper flow well to our north, along
with some h85 downslope flow, well above normal temps expected.


Models continue to indicate a dry front moving through the area
Sunday night/early Monday. High pressure center to ridge down the
eastern seaboard, and also indicate a building upper ridge over
the SE CONUS, ensuring dry conditions. Some cooler air to enter
the region behind the front, but still above normal temps


Possible MVFR restrictions in fog or stratus this morning but
confidence remains low due to thick high clouds limiting
radiational cooling.

Surface high pressure centered over New England continues to ridge
into the Carolinas while an upper trough over the western Ohio
Valley and Mississippi Valley approaches from the west.
Atmospheric moisture remains quite low with precipitable water
values around a half inch or so although surface dewpoints have
come up about 10 degrees from yesterday. A blanket of high clouds
is expected to remain over the region through dawn and will limit
radiational cooling. VAD wind profile indicating light
southeasterly flow at 1000 ft which will help advect better
moisture into the area today.

MOS guidance suggests a brief period of stratus or fog developing
10z-13z time frame all terminals but hi-res model guidance not
showing the same scenario leading to low confidence in this
forecast. Given the dry air in place and thick cloud deck above
will go with more optimistic vsby forecast and move prevailing fog
from previous forecast into TEMPO groups. Light to calm winds will
increase from the south to around 5-8 knots after 14z. Any stratus
that does develop should dissipate by 15z or so with mixing.

As a cold front approaches late afternoon there is a low chance of
convection during peak heating with cooler temperatures aloft but
expect most of it to remain north of the terminals.

EXTENDED AVIATION OUTLOOK...Fog or stratus possible Friday morning
with some lingering low level moisture over the region.




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