Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Charleston SC
613 PM EDT Tuesday Oct 13 2015
a weak cold front will cross the area tonight then dry high
pressure will build in through early next week.
Near term /until 6 am Wednesday morning/...
13/22z surface analysis placed a cold front roughly along a klgc-
kahn-kclt-kdan line. The front will move steadily east tonight and
is prognosticated to push off the coast early Wednesday morning. High
resolution models still show isolated showers/thunderstorms moving across
southeast South Carolina and southeast Georgia over the next few
hours along what appears to be a subtle pre-frontal trough...but
early evening water vapor imagery shows middle-level dry air quickly
eroding a narrow band of moisture that is traversing the area.
This will likely preclude any meaningful shower activity from
developing so an update has been issued to remove mentionable probability of precipitation
for the evening period. A band of thick altostratus will move
east over the next few hours and provide a period of mostly cloudy
skies...but skies are poised to clear steadily later this evening
Short term /6 am Wednesday morning through Friday/...
Wednesday...at daybreak a cold front will be located well
offshore and surface high pressure will be building in from the
northwest. Precipitable waters dropping well below normal to around 0.5 inches
will keep a dry forecast in tact. Westerly downslope flow and
sunny skies will support high temperatures around 80 in most
Thursday and Friday...the high will shift overhead and allow for
the quiet and dry weather to continue. Highs will be near normal
in the upper 70s/around 80. Favorable radiational cooling
conditions will allow low temperatures to drop to the upper 40s
inland...middle 50s closer to the coast.
Long term /Friday night through Tuesday/...
a reinforcing cold front will drop through the area on Saturday with
cool Canadian high pressure building in its wake. Low temperatures will dip
into the 40s Saturday night and Sunday night while high temperatures Sunday
and Monday remain in the 60s in most locations. As the parent
surface high shifts east early next week a coastal trough will
develop. Isolated showers possible over the Atlantic waters Monday
night through Wednesday.
Aviation /22z Tuesday through Sunday/...
Extended aviation outlook...there are no concerns.
tonight...breeze southwest winds will persist this evening as a
cold front approaches from the west. Winds will begin to diminish
later this evening as a pre-frontal low-level jet shifts farther
offshore. The highest winds will be found along the Charleston
County coast where speeds will remain 15-20 knots. A few gusts to 25
knots could occur...but their durations appear low enough to preclude
the issuance of a Small Craft Advisory. Seas this evening will
average 2-4 feet...locally higher off the Charleston County
coast...then will begin to subside overnight as winds turn
Wednesday through Sunday...marine conditions will remain quiet
through the end of the work week as surface high pressure remains
in control. Winds will generally be less than 15 knots and seas
1-3 feet. A cold front will cross the waters on Saturday with
northeast winds behind the front possibly approaching Small Craft
Advisory criteria late Saturday into Sunday.