381
FXUS62 KCAE 140813
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
413 AM EDT Sun Jul 14 2024

.SYNOPSIS...
Expect isolated to scattered diurnally driven showers and
thunderstorms this weekend and early next week with above normal
temperatures. Warm and humid conditions continue through the
end of the long term with increasing rain chances late next week
as a cold front likely stalls across the Southeastern US.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Message(s):

- Highs around 100 degrees with HI values around 105 today

The overall synoptic pattern is very similar to the previous day
with PWAT values from 1.6 to 1.8 over the area and ridging aloft.
Temperatures should be a little warmer today than yesterday with
850mb temps a degree C or two warmer. MOS guidance, which was a 1-2
degrees F too cool yesterday in the Augusta area and 3-5 degrees F
too cool for the Columbia area, is coming in from 96 to 101 today.
Charnick local scheme gives 101 to 103 at CAE accounting for cloud
cover and dry soils. This adds confidence in highs in the upper 90s
and up to 103 degrees today for most of the area. Similar to
yesterday, only isolated, weak showers/storms are expected given the
warm temps aloft. So this should not cause too much disruption in
the diurnal trend. That said, we will be right around Heat Advisory
criteria today with afternoon dewpoints ranging from mid 60s to low
70s. The minimum NBM hourly dewpoints from yesterday verified very
well and were used to calculate today`s dewpoints/Heat Index.
Maximum HI values topped out right around 108. CAMs show some
lingering, isolated convection into the early evening along a
possible sea breeze. But any activity should diminish in the evening
with lows overnight in the mid 70s.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
Key Message(s):

- Increasing chances of mainly afternoon and evening convection
  each day
- High temperatures in the upper 90s to around 100 degrees with
  the potential for a Heat Advisory Monday and Tuesday

Synoptically the pattern will begin shifting through the short
term with zonal flow over the eastern US Monday with a trough
beginning to dig into the Upper MS Valley on Tuesday. At the
surface high pressure well off the East Coast will remain in
control of the area and with easterly flow persisting continue
pushing moisture into the region. Pwat values will will be
around 2 inches across much of the area and slightly higher in
the eastern Midlands on Monday with values over 2 inches
expected Tuesday. Instability will be moderate to strong each
day however with the zonal flow aloft a defined trigger
mechanism will be lacking. In addition winds through the column
will be 20 knots or less with little to no divergence aloft. As
such with temperatures in the upper 90s to around 100 each day
expect diurnal showers and thunderstorms to develop each day
with slight chance to low chances on Monday and moderate chances
on Tuesday due to increasing moisture. The concern for locally
heavy rainfall will continue due to the weak steering flow and
any training will increase the concern.

Heat index values will also require monitoring as values each
afternoon are expected to be in the 105 to 108 degree range and
possibly higher. Will continue to monitor the potential and
issue heat advisories as needed.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Key Message(s):

- Gradual cooling trend possible Wednesday through Saturday
- Showers and thunderstorms expected each day

The synoptic pattern will continue changing as the upper level
trough continues digging into the eastern US with the trough
axis stretched from New England into the Lower MS Valley
Thursday afternoon then gradually ejecting eastward through
Saturday. At the surface high pressure will remain in control of
the western Atlantic as low pressure moves north of the Great
Lakes while dropping a frontal boundary toward the SE US.
As is typical for this time of year the frontal boundary will
struggle to reach the forecast area however it will help to act
as a focusing and trigger mechanism. This will result in
moisture convergence across the SE US Wednesday through
Saturday with pops currently in the high chance to low likely
range. With the area in extended dry conditions and models
having been aggressive with pops recently have remained on the
cautious side however the scenario painted by the models is
encouraging. With the increasing potential for daily convection
and associated cloud cover temperatures will be gradually
lowering each day. High temperatures Wednesday will be in the
mid to upper 90s with mid 80s to around 90 for Friday and
Saturday.

&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
Brief period of MVFR/IFR conditions possible early this morning.
Otherwise VFR likely.

Some patchy stratus and fog is possible this morning, particularly
at OGB. Confidence is low in widespread restrictions but high
enough for tempo MVFR mentions for vsby between 08-13z. Winds
will pick up slightly out of the west from 5 to 10 kts for today
diminishing in the evening. Convective activity should be
similar to the previous day with weak, isolated showers or
thunderstorms diminishing in the evening. Low coverage limits
chances that convection will impact terminals. As has been the
case the past few days patchy fog or areas of stratus may occur
during the early morning hours but confidence is low.

EXTENDED AVIATION OUTLOOK...Typical summertime afternoon
showers and thunderstorms may cause periodic restrictions each
day with abundant moisture causing possible, brief early morning
restrictions.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.

&&

$$