Area Forecast Discussion
Issued by NWS Columbia, SC-- Highlight Changed Discussion --
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FXUS62 KCAE 301049
Area Forecast Discussion
National Weather Service Columbia SC
649 AM EDT Thu Mar 30 2017
Moisture return, daytime heating, and a stationary front will
provide a chance of showers and thunderstorms this afternoon
and evening. The front will lift north as a warm front tonight
ahead of an upper trough and cold front that will move through
Friday morning, providing a continued chance of thunderstorms,
possibly severe. Drier air will enter the region behind the
departing system Friday afternoon, with high pressure building
into the Mid Atlantic ensuring fair weather through Sunday.
Next system to affect us Monday and provide a chance of showers
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Early morning weather analysis indicates a deep closed upper low
over Kansas with a cold front extending southward through
Arkansas and Texas while a warm front was situated across
Tennessee into central Georgia. Satellite imagery shows coastal
stratus has expanded northwestward into the Midlands associated
with moist onshore low level flow. Weak ridging down the east
coast will shift offshore today as the warm front to our south
lifts northward with southerly flow developing ahead of the
approaching upper low.
Despite morning cloudiness, expect low clouds to break when the
inversion breaks and stratus deck will transition to
stratocumulus or cumulus as surface heating takes place and
instability develops. Moderate instability is forecast this
afternoon across the Midlands/CSRA with lifted index values
around -5C and CAPE values around 1000-1500 J/kg. Hi-res models
are in reasonable agreement showing convective initiation
occurring around 18z-19z and expanding across much of the
southwestern two-thirds of the forecast area. Shear is not great
but could be sufficient enough to sustain isolated severe
thunderstorms from convection that initiates in the vicinity of
the warm front which will provide a focus for the convection.
Cold air aloft with 500mb temps around -14C and wetbulb zero
height around 10kft will support a marginal large hail threat
along with isolated damaging wind gusts. SPC has outlooked the
forecast are in a marginal risk with the slight risk just to our
Temperatures are challenging today with low clouds in place this
morning and temperatures starting off quite warm in the lower
60s. Just a couple of hours of sunshine after the clouds break
should allow temperatures to rise into the mid-upper 70s with
lower 80s in the CSRA. Depending on how early and where convection
initiates, that may limit temperatures as well.
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
Main focus will be on thunderstorm chance and severe weather
potential tonight into Friday morning. Upper trough will move
through late tonight/Friday morning. Surface front to begin
lifting north as a warm front ahead of the approaching
system/cold front. Though some diurnal stabilization expected,
sufficient instability combined with considerable shear
expected to provide a severe threat. SPC has our FA in a MRGL
to SLGT risk of severe. Cold front to move through by Friday
afternoon, with drier air filtering into the region. Breezy
conditions possible Friday afternoon.
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Upper ridge will shift into the SE CONUS Sat/Sun, while surface
high builds into the Mid Atlantic, ensuring fair weather for
our FA. GFS/EC indicate next upper trough/surface front and
moisture return to provide a chance of showers and thunderstorms
Mon/Mon nt into Tue time frame, with another system possible
late in the forecast period or just beyond.
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --High confidence in MVFR ceilings at the beginning of the 24 hr
forecast period with IFR ceilings also possible late tonight.
Fog channel satellite imagery showing widespread stratus
over the Midlands and CSRA and expect clouds to continue to
be over all terminals through 15z resulting in MVFR cigs. The
exception may be OGB which is on the edge of the clouds now but
redevelopment is likely. Vsbys never went down due to winds
staying up and not expecting them to drop through sunrise.
A weak warm front south of the area will lift northward into the
Midlands today and provide a focus for convection after 16z.
Expect all terminals to be affected by convection with showers
and scattered thunderstorms between 18z-00z. Hi-Res models
providing some possible timing of thunderstorms so have included
a tempo group for thunder at each site covering a 3 hour window.
Strong and damaging winds will be possible with the
Restrictions should return overnight with low clouds
redeveloping at least at CAE/CUB as some wedge conditions try to
re-establish before the stronger upper system arrives towards
morning Friday which will bring another chance for showers and
storms. Did not mention thunder at this time for the second
round of convection as there is some uncertainty it will impact
EXTENDED AVIATION OUTLOOK...Restrictions possible in showers
and thunderstorms Friday and on Monday as cold fronts cross the
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