Area Forecast Discussion
Issued by NWS Columbia, SC
FXUS62 KCAE 250959
Area Forecast Discussion
National Weather Service Columbia SC
559 AM EDT MON JUL 25 2016
High pressure over the region will keep above normal temperatures
in the forecast through the end of the week. Isolated to scattered
thunderstorms are possible each afternoon and evening. Moisture
and instability will increase for the weekend.
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...Isolated showers developing across the central and
southern Midlands into the CSRA this morning. Weak low level
convergence and perhaps a weak short wave crossing the Midlands in
southeast flow aloft. Have increased cloud cover and pops for this
region...but kept pops below 20 percent.
Previous discussion...High pressure at the surface and aloft
will continue over the region through tonight. Warm temperatures
aloft and weak instability will limit convection. Could see
isolated to widely scattered thunderstorms along the sea breeze
this afternoon and near a lee side trough over the piedmont of SC
into northern GA this afternoon and evening. Have ranged pops from
around 10 percent over the Pee Dee region to near 20 percent
southern Midlands and CSRA. We continued temperatures near
guidance consensus with afternoon highs in the mid 90s to around
100 degrees and lows tonight in the low to mid 70s. Heat indices
should peak in 100 to 106 degree range this afternoon.
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
The mid/upper level heights will remain strong across the area.
Models indicate one upper level ridge center over the desert
southwest and another over the Carolinas and Georgia. We will see
little change in our weather as Bermuda high pressure at the
surface ridges into the southeastern states. Models do not
indicate much in the way of forcing as most of the s/w activity
will stay north of the area. PW values will range from 1.5 to around
2.0 inches and only expect isolated/widely scattered convection
each afternoon. Temperatures will remain above normal with
afternoon highs in the mid 90s to near 100 degrees and lows in
the 70s. Heat indices will range from 100 to around 106 degrees.
.LONG TERM /THURSDAY THROUGH SUNDAY/...
Both GFS/ECMWF indicate that the mid/upper level ridge of high
pressure centered along the southeast coast will remain there
through the end of the week. By the weekend...a much strong s/w
will begin to move across the Midwest/Great Lakes region. At this
time...the ridge will begin to move eastward and heights begin to
fall over the area over the weekend. Models have had a hard time
with strength and speed of system and confidence remains low that
pops will increase late and temps will cool somewhat. Have
continued with slight chance/low chance pops for late week then
increased them slightly over the weekend. Expect above normal
temperatures through the period...but could see a slight decline
by the weekend...depending on cloud cover. Expect highs in the
mid/upper 90s with overnight lows in the low/mid 70s.
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
VFR conditions to dominate the period.
Some mid and upper level cloudiness lingering overnight and a low
level jet around 25 knots will inhibit fog formation.
Monday, an upper level ridge overhead and warmer 500 mb heights
suggests afternoon convection will be weak and isolated. Hi-Res
models are favoring the most activity in the CSRA, being further
away from the center of the upper ridge. Expect south winds from 5
to 10 kts.
Monday night, models indicate drier low levels and some mixing
associated with a LLJ. Fog potential will be limited. South winds
will continue into the evening becoming variable overnight.
EXTENDED AVIATION OUTLOOK...Low confidence in restrictions
in afternoon and evening convection each day. Low potential for
brief periods of early morning fog...mainly at AGS/OGB.