FXUS62 KGSP 261853

AFDGSP



Area Forecast Discussion

National Weather Service Greenville-Spartanburg SC

253 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 206 PM Thursday: 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. ACARS soundings remain capped east of the mountains 

with a dearth of cumulus across much of the area. The best portion 

of the cumulus field is across northern Iredell into Davie county, 

but even then the quality of the cumulus is sub-par at best. A few 

cumulus have been trying to get going along the I-85 corridor in the 

Upstate, but once again very unimpressive. The mountains are a 

different story, however, where mechanical forcing has helped 

develop scattered strong to severe storms already this afternoon. A 

threat for isolated damaging winds and small hail will continue over 

the mountains for the next several hours where moderate instability 

has been able to develop. Confidence quickly wanes east of the 

mountains owing to the previously mentioned lack of cumulus field. 

An earlier outflow boundary pushing down the Hwy 321 corridor into 

Hickory failed to initiate any new updrafts owing to the shallow 

depth of the cold pool and rather high LFCs. The story is the same 

across the Upstate where a previous boundary also failed to 

instigate new convection. Regardless, a couple isolated to widely 

storms may be able to get going later this afternoon into early this 

evening as heating maximizes, but may also remain rather muted. The 

environment isn't anywhere near as favorable for severe storms today 

compared to yesterday as the residual EML has pushed out of the area 

with less impressive lapse rates and only modest instability. DCAPE 

remains the most impressive parameter and any isolated deeper cores 

that are able to develop could contain locally strong to damaging 

winds.



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 /19Z THURSDAY THROUGH TUESDAY/...

At KCLT and elsewhere: VFR conditions are ongoing at most terminals 

early this afternoon but another round of afternoon showers and 

thunderstorms is already underway. Temporary restrictions from 

thunderstorms will be possible at KAVL and KHKY over the next 

several hours. Activity may spread farther east through the rest of 

the afternoon with restrictions possible along the I-85 terminals. 

Any storms should dissipate this evening with loss of daytime 

heating. VFR conditions will prevail overnight with the exception of 

any patchy fog, especially in mountain valleys. Confidence is too 

low to warrant mention in any TAFs at this point. Another batch of 

afternoon storms will be possible again tomorrow.



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...Heat Advisory until 8 PM EDT this evening for NCZ036-037-057-

     071-072-082.

SC...None.



&&



$$



SYNOPSIS...DEO

NEAR TERM...TW

SHORT TERM...RWH

LONG TERM...RWH

AVIATION...TW

