FXUS62 KGSP 261727

AFDGSP



Area Forecast Discussion

National Weather Service Greenville-Spartanburg SC

127 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 TONIGHT/...

As of 928 AM Thursday...



Key Messages:



1) Hot and Humid Again but not as Hot or Humid as the Last Two Days



2) Heat Advisory in Effect from 2PM to 8PM Along the I-77 Corridor



3) Another Round of Strong to Severe Storms Develops this Afternoon 

and Evening but Coverage and Intensity Should be Less than Yesterday 



A couple stray showers continue to drift across the area with a 

couple returns over the mountains and another small shower over 

Lincoln County. Overall, the forecast remains dry through the rest 

of the morning before another round of diurnally driven storms this 

afternoon. No changes were needed with this update.



Weak upper ridging remains over the eastern United States while a 

weak upper low lifts northward over Florida through the period. This 

will allow the heat and humidity to lower just a bit today (we will 

take any relief we can get at this point). Temps this afternoon will 

end up ~3-4 degrees cooler compared to yesterday but will still end 

up around 5-10 degrees above normal. Highs will range from the low 

to mid 90s east of the mountains and the upper 80s to lower 90s 

across the mountain valleys. Triple digit heat indices are once 

again expected, mainly east of the NC mountains. However, the 

Caldwell, Burke, McDowell, Rutherford and Polk mountain zones will 

see triple digit heat indices return today. Locations along/near the 

I-77 corridor are most likely to reach Heat Advisory criteria this 

afternoon/early evening so the Heat Advisory remains in effect from 

2pm to 8pm. Heat indices in the advisory will range from 105-108 

degrees F. Another round of strong to severe storms can be expected 

this afternoon and evening but activity is not expected to be a 

robust as what we saw yesterday. Although deep layer shear will 

increase slightly, ranging from 10-15 kts, both SBCAPE and DCAPE 

will a few hundred J/kg lower than yesterday. SBCAPE should 

generally range from 2,000-3,000 J/kg with DCAPE ranging from 900-

1,300 J/kg per the latest high res guidance and model soundings. The 

Day 1 SPC Severe Weather Outlook has the entire forecast area in a 

Marginal risk for severe storms and this appears warranted based on 

the expected environment today. Damaging wind gusts from microbursts 

will continue to be the main hazard with any severe storms that 

develop but isolated, brief large hail is also possible. The Day 1 

WPC Excessive Rainfall Outlook has most of the forecast area in a 

Marginal risk so the isolated heavy rainfall/flooding threat will 

return again today (especially for areas that saw heavy rainfall 

yesterday and that get heavy rainfall again today). 



Drier conditions will gradually develop late this evening into 

tonight once convection wanes. Lows tonight will be similar to this 

morning, ending up around 5-8 degrees above normal. Patchy mountain 

valley fog and low stratus should develop again tonight into 

daybreak Friday.



&&



.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...

As of 250 AM EDT Thursday: The pattern will remain unsettled with

showers and storms expected again Friday and Saturday. 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 andlee 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 can be expected both days from mid aftn to early

evening. Also, weak steering flow and elevated PWATs will yield an

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

to be slightly above normal, with highs in the upper 80s in the

lowest mountain valleys and lower 90s east of the mountains. Lows

in the 60s in the mountains and generally 68-74 east. Dewpts do

not mix out much either day, keeping heat indices elevated and

possibly topping out in the 100-105 deg F range in the southern

Upper Savannah Valley and the Charlotte area. But not expecting

to need a Heat Advisory either day.



&&



.LONG TERM /SUNDAY THROUGH THURSDAY/...

As of 300 AM EDT Thursday: A weak upper low will open up into a

relative weakness in the subtropical ridge over FL/GA Sunday,

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 Sunday thru Tuesday

than what we're expecting Friday and Saturday. 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. Sever 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. So while PoPs are lower, they are

still elevated for Wednesday (50-70%).



&&



.AVIATION /18Z 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...ARK

NEAR TERM...AR/TW

SHORT TERM...ARK

LONG TERM...ARK

AVIATION...TW

