Area Forecast Discussion
Issued by NWS Columbia, SC

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FXUS62 KCAE 281522

Area Forecast Discussion
National Weather Service Columbia SC
1122 AM EDT Sun May 28 2017

Ridging over the region will weaken on Sunday as a frontal
boundary slowly slides into the area. The front will stall over
the area early this week providing chances of showers and
thunderstorms each day through Saturday.


Upper ridge to our south, with upper trough over the central
CONUS. A series of upper impulses will move east, tracking mainly
just to our north. Surface wave over NC with surface
front/trough stretching back to the west, appears will generally
remain in place due to nearly parallel flow aloft. Combination
of better moisture, upper energy and surface boundary providing
focus for clusters of thunderstorms along this area.

Some varying solutions in latest high-res models regarding
convection later today. Model solutions range from completely
capped with no convection developing to scattered thunderstorms
across the CWA. The mid level cap will weaken throughout the day
which may allow the best chance of convection later this
afternoon as an upper level shortwave moves across the Midlands.

Strong instability and considerable deep layer shear forecast
today. Temperatures expected in the lower 90s to support
isolated to scattered convection with a severe threat. Damaging
winds appear to be the primary threat given a freezing level
around 15kft and fairly unidirectional hodographs.


Upper level ridge will remain to our south, with upper trough to
our north. Westerly flow aloft with embedded impulses. Surface
low pressure well to our N/NE will shift farther NE and bring
down a weak surface boundary slightly farther south into the
northern/central FA, along with some continued increase in
moisture. Model blend yields chance POPs. Strong instabilities
Monday will provide a severe threat. SPC has region in SLGT risk
for severe Monday.


No changes made to the ongoing forecast for this time period.
Previous discussion follows: Models are in good agreement
through the long term with some differences in location on
Friday and Saturday. Frontal boundary will remain stalled over
the region through the period with potential for convection each
day. Tuesday currently presents some concern as instability
will be moderate...pwat values around 1.6 inches and SPC slight
risk for the area. Chances of convection will continue Wednesday
through Saturday...however with the front becoming more diffuse
across the region potential for severe convection is currently
lower. Temperatures will be near to slight above normal with
afternoon highs in the mid 80s to low 90s and overnight lows in
the mid 60s to around 70.


VFR conditions generally expected through the 24 hr forecast
period, although some restrictions could be possible in
scattered convection.

The question for the remainder of the day will be how possible
convection may evolve this afternoon and evening given abundant
debris clouds this morning. Strong instability is forecast and
low level moisture is sufficient to support scattered convection
but little agreement of strong signals in hi-res models for
convection over the area leading to lower confidence. So at this
time with low pops forecast have decided to leave mention of
possible convection this afternoon out of the forecast with warm
temperatures aloft once again and weak high pressure over the

Winds will generally be from the west today around 10 knots with
some gusts to 20 knots possible this afternoon ahead of an
approaching frontal boundary. Low level jet overnight and cloud
cover should limit fog development tonight.

EXTENDED AVIATION OUTLOOK...A cold front will stall over the
region through early next week. The front will help support
scattered thunderstorms and possible restrictions.




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