Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Columbia SC
312 am EST Wednesday Nov 26 2014
low pressure off the South Carolina coast this morning will lift
northeast today. Widespread rain this morning will end early this
afternoon. A clipper type system will cross the central
Appalachians late tonight...dragging a dry cold front across the
area. Dry high pressure will build into the region Thursday
Near term /through today/...
deep upper trough axis to our west...with upper high to our southeast
over the western Atlantic...resulting in a SW upper flow for our
region. Surface low pressure off the SC coast early this morning
will continue moving northward along a stalled frontal boundary.
Widespread rain across the area still expected end late morning
through early afternoon from southwest to northeast as the area of
low pressure deepens and lifts away from the Carolinas...and
drier air filters into the region. Should see clouds begin to
decrease by late afternoon. Kept temperatures near guidance
consensus for highs in the upper 40s north to upper 50s south.
Short term /tonight through Thursday night/...
an upper level trough will swing across the region tonight into
Thursday. The deepening coastal surface low will continue up the
North Atlantic coast. A clipper type system over the northern
plains will cross the central Appalachians late tonight...dragging
a dry cold front across our area. There will be an increase in
clouds with this system...but no precipitation is expected given
precipitable water less than one half of an inch. Sunshine will return Thursday
with high pressure building in from the west by the afternoon.
Low tonight should range from the middle 30s to lower 40s.
Temperatures remain below normal for Thursday with highs in the
50s. Freezing temperatures are on tap for Thursday night with
clear skies and cold air advection.
Long term /Friday through Tuesday/...
high pressure will build in Friday through the weekend. Good
radiational cooling Friday night with overnight mins in the upper
20s to lower 30s. Below normal temperatures Friday and Saturday
will warm into the 60s Sunday and Monday. Both the GFS and European model (ecmwf)
are indicating the development of a wedge for Tuesday. This could
mean below normal temperatures and a chance of rain.
Aviation /08z Wednesday through Sunday/...
light rain continues to stream northeast from central and
coastal Georgia into the area. Ceilings and visibilities have lowered
slightly with most taf sites reporting IFR/MVFR conditions. Expect
IFR/MVFR through middle morning. A frontal boundary remains stalled
along the South Carolina coast. A low pressure tonight over central
Florida will continue to track northeast for the remainder of the
night and then exit the SC coast by later this morning. Expect
moisture flux/isentropic lift to increase across the region
overnight which should result in more widespread rain...moderate
at times. The low center will push northeast of the South Carolina
coast by this afternoon and winds should shift to northwest
and allow drier air to filter into the region...so conditions
should improve by 18z to VFR although strato-cumulus deck possible
through end period. Winds will increase during the morning through
early afternoon as low along the North Carolina coast deepens.
Already seeing some increase in winds across the csra and along the
coastal plain as the pressure gradient continues to tighten. By
later this morning into the early afternoon hours...expect northwest
winds gusting to around 20 knots...but diminishing by late afternoon.
By this evening...expect VFR conditions with diminishing winds from
Extended aviation outlook...expect VFR conditions for the remainder
of the period.
SC...Flash Flood Watch through this evening for scz030.