FXUS62 KGSP 262332

AFDGSP



Area Forecast Discussion

National Weather Service Greenville-Spartanburg SC

732 PM EDT Thu Jun 26 2025



.SYNOPSIS...

The upper ridge which was responsible for the very hot weather we 

have had will gradually weaken, allowing temperatures to get closer 

to normal through the weekend. A disturbance meandering over the 

Deep South will help produce mainly afternoon and evening showers 

and thunderstorms each day.  A weak cold front reaches our region by 

Tuesday and becomes stationary west to east through mid week.



&&



.NEAR TERM /THROUGH FRIDAY/...

As of 725 PM EDT Thursday: Most of the showers and thunderstorms 

from earlier in the afternoon has quickly dissipated with the loss 

of peak heating and overturned atmosphere. Still a few storms worth 

keeping an eye on along and east of the I-77 corridor where the 

atmosphere is somewhat left untapped. Can't ruled out areas of 

stratiform precip lingering through the evening hours in the 

southwest mountains, northern Upper Savannah Valley, and east of I-

77. Otherwise, the forecast remains on track with only minor tweaks 

made based on current observations and latest radar/satellite trends.



A flat upper ridge extends from the Tennessee Valley to the Mid-

Atlantic with a weakening upper low associated with a Tropical Upper 

Tropospheric Trough centered over Florida. The airmass over the 

western Carolinas and Georgia has been slow to recover today 

following significant overturning during yesterdays vigorous storms.



Any storms should wane fairly quickly this evening with loss of 

heating with a rather benign overnight period expected. Valley fog 

will once again be possible, especially across the Little Tennessee 

Valley. A more seasonable summertime pattern returns tomorrow with 

"cooler" highs in the upper 80s to low 90s and heat indices well 

below advisory criteria, although a few readings in the low 100s 

cannot be ruled out. Another batch of diurnally driven thunderstorms 

is once again expected with the greatest coverage over the mountains 

again. Coverage east of the mountains remains uncertain, especially 

east of I-85. As is the case with any summer storms, a few wet 

microbursts cannot be discounted but the environment will remain on 

the lower end for microburst potential.



&&



.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...

As of 240 PM EDT Thursday: The pattern will remain unsettled with 

showers and storms expected again Saturday and Sunday. Coverage 

should be enhanced with an upper diffluent pattern in between a weak 

upper low near FL and a flat trough over the Great Lakes. The 

typical mountaintop and lee trough convergence will be the triggers 

for convective initiation, and shear and thermal profiles will 

support a pulse storm mode. The NBM has categorical PoPs in the 

mountains tapering to likely in the Foothills and high-end chc 

southeast of I-85. This seems a little high, but over a 12-hour 

period, coverage may largely verify these values. A few strong wet 

microbursts are possible both days from mid aftn to early evening. 

Also, weak steering flow and elevated PWs will yield an 

isolated/localized heavy rain/flood threat. Temps will continue to 

be slightly above normal. Dewpts mix out a little both days, but 

heat indices max out around 100 and possibly higher in the southern 

Upper Savannah Valley and the Charlotte area. Not expecting to need 

a Heat Advisory either day.



&&



.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...

As of 250 PM EDT Thursday: A weak upper low will open up into a 

relative weakness in the subtropical ridge over FL/GA Monday, while 

a northern stream trough digs into the Great Lakes and Ohio Valley. 

This set up should keep enhanced diurnal convection going thru the 

first half of next week. In fact, the deterministic guidance shows 

even more convective response Monday and Tuesday than what we're 

expecting in the previous days. The digging trough will bring a weak 

cold front SE toward the forecast area and may provide extra 

convergence for convection Tuesday. Pretty much every day has 

similar PoPs and temps, with a slight uptick in PoPs and a slight 

downward trend in max temps Tuesday. The above-climo PoPs may 

increase excessive rain/flash flood threats as we continue with this 

pattern. Severe threat should remain a few wet microbursts each day, 

with perhaps an increase in more organized storms Tuesday thanks to 

a little more shear and upper divergence associated with the digging 

upper trough.



There is disagreement between the GFS and ECMWF on whether the cold

front will push far enough thru the forecast area to dry us out

and bring temps back to normal. The GFS hangs the front up across

the Piedmont, while the EC pushes it to the I-20 corridor. It's

difficult for a front to clear thru the area this time of year,

and the EC seems to be on the more amplified side of the LREF 

guidance on the 500 mb trough. That said, the guidance blend does 

lower PoP into the chance range for Thursday.



&&



.AVIATION /00Z FRIDAY THROUGH TUESDAY/...

At KCLT and elsewhere: VFR conditions will prevail through most

of the forecast period. Most of the showers and thunderstorms

from this afternoon have dissipated and moved far enough away

from the terminals to take out any thunderstorm mention through

the rest of the evening and overnight tonight. Kept a mention

of lingering VFR convective debris through tonight, but likely

scatters out completely by the early morning hours Friday. Not

expecting widespread low stratus or fog except in the mountain

valleys and placed a TEMPO mention for 5SM and FEW007 at KAVL

just before daybreak, but per usual, this forecast is typically

boom or bust. Another round of afternoon showers and storms with

associated restrictions are expected Friday, so placed a PROB30

at all TAF sites. Welcome to Summer.



Outlook: Daily chances for afternoon and evening showers and

thunderstorms continue into next week. Fog and/or low stratus will

be possible each morning in the usual mountain valleys as well as

near lakes and rivers.



&&



.GSP WATCHES/WARNINGS/ADVISORIES...

GA...None.

NC...None.

SC...None.



&&



$$



SYNOPSIS...DEO

NEAR TERM...CAC/TW

SHORT TERM...RWH

LONG TERM...RWH

AVIATION...CAC

