348
FXUS62 KGSP 020720
AFDGSP

Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
320 AM EDT Tue Jul 2 2024

.SYNOPSIS...
Dry and relatively cool high pressure will remain in place today,
before temperatures start warming back up tomorrow and beyond.
Especially hot and humid conditions are expected over the weekend.
Scattered afternoon showers and thunderstorms will be possible
Thursday and beyond, especially over the mountains.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 225 AM EDT Tuesday...Fair weather will continue for the rest
of the overnight, but a pesky cloud deck has developed underneath
the inversion in the vicinity of the Blue Ridge Escarpment. The
extra cloud cover will probably keep temps a bit warmer underneath,
impacting the lows.

An upper ridge to the west and sfc high pressure moving from
NY/PA to the southern New England Coast over the next 24 hours
will set us up for a welcome relief from the heat and humidity
across the region. Once we get more dry air to advect in from
the northeast later this morning to take care of the cloud cover
banked up along the Escarpment, we should get plenty of sun for
the afternoon. The air mass will be nice for early July, with high
temps topping out a few degrees on the cool side of average. The
lack of humidity will be the bigger story, as dewpoints drop off
to the middle 50s this afternoon and drop the RH into the 35-40%
range. All this should preclude any chances of rain. Enjoy it if
you can because it won`t last, of course. By Wednesday morning,
the center of the upper anticyclone will drift eastward and that
should start us back on a warming trend.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
As of 225 AM EDT Tuesday: Quiet conditions will continue on
Wednesday as ridging remains established over the Carolinas
and high pressure over the western Atlantic spurs increasingly
S flow at the low-levels.  This will slowly but surely usher in
better moisture above the boundary layer through the period, but
functionally won`t have much effect on the pattern.  Some isolated
showers will be possible west of I-26 on Wednesday afternoon, as
temperatures surge into the upper 80s and lower 90s again...but it
should stay dry enough that afternoon heat index won`t be an issue.

By Thursday, improving moisture flux will permit better coverage
of diurnal showers over the NC mountains and Savannah River Valley,
and afternoon dewpoints will reach the low 70s again.  For isolated
locations mainly along and south of I-85, this could mean the
first afternoon of heat index values back near or above 100 degrees.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 244 AM EDT Tuesdsay: Things will heat up going into the
weekend as moisture continues to stream in off the Atlantic and
Gulf of Mexico.  A series of upper waves will chip away at the
subtropical ridge over the Southeast through Friday and the first
part of the weekend, pushing it gently eastward and opening up
the Carolinas to somewhat better dynamics.

For Friday, that probably means a forecast similar to Thursday
in terms of coverage of showers, though it`ll perhaps be muggier.
By Saturday, a more robust wave drifting across the Great Lakes and
Quebec will spur surface cyclogenesis over the Midwest and upper
Ohio Valley, and the trailing sfc cold front will make tracks
toward the forecast area, inciting better coverage of showers,
and potentially some decent thunder chances, over the forecast
area during the afternoon.  Jury`s still out on whether this
front will hold together as it approaches the area...but LREF
members seem to favor it faltering and keeping us in the moist
southerly regime we`ll have been in for days by this point.  So,
afternoon heat index values of 100-105 can be expected across the
southern half of the forecast area both Saturday and Sunday...even
if dewpoints fall on the drier side of current guidance.

Monday and beyond, as ridging slides ever farther east, it`ll
lose some influence on the pattern.  Temperatures will drop
somewhat starting out the new week, and better diurnal showers
and thunderstorms should continue.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: VFR through the period at all
terminals. There is a pesky stratocu deck that has developed
underneath the subsidence inversion along and around the Blue Ridge
Escarpment that may impact some terminals with a VFR-level bkn
ceiling through daybreak or until some drier air advects into the
region. Cloud bases will be generally 040-060. The low clouds are
expected to mix out as we warm up Tuesday morning. Wind should be
easterly overnight, then with some backing to NE during the day,
then veering back to SE as the center of high pressure shifts
toward the Mid-Atlantic Coast tonight.

Outlook: Dry high pressure remains in place through Wednesday. A
return of more typical mid-summer diurnal convection is expected
starting on Thursday and will linger into the weekend.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

$$

SYNOPSIS...MPR
NEAR TERM...PM
SHORT TERM...MPR
LONG TERM...MPR
AVIATION...PM