textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Shower and thunderstorm chances increased slightly over the mountains for the weekend.

Heat indices are trending warmer for the beginning to middle of next week.

KEY MESSAGES

1. Shower and thunderstorm chances return by the end of the week and into the weekend. 2. Temperatures trending warmer through the weekend with triple digit heat indices possible for some locations east of the mountains.

DISCUSSION

Key message 1: Shower and thunderstorm chances return by the end of the week and into the weekend.

High pressure remains dominant across the southeast through Thursday night, keeping the CWA relatively dry. By Friday, the area remains under mostly zonal, stagnant flow aloft while the surface over the Atlantic migrates westward. The western fringe of the high should start advecting moisture once again into the southeast, increasing shower and thunderstorm chances each afternoon. Currently, the higher chances (40-60%) for storm activity appear to be concentrated over the mountains. This appears to be more of the typical summertime, diurnally driven convection that occurs over the mountains. By Sunday, there is a slight chance (20-30%) for a few isolated showers or thunderstorms east of the mountains. Severe weather is not expected at this time.

Key message 2: Temperatures trending warmer through the weekend with triple digit heat indices possible for some locations east of the mountains.

The overall pattern is shaping up to increase temperatures and moisture, increasing the chances for triple digit heat indices for a portion of the CWA. Guidance signals for an amplifying ridge out west pushing eastward toward the central and eventually eastern portion of the CONUS. As this ridge moves eastward and high pressure builds in over the southeast, temperatures climb. Saturday and Sunday look to be the warmest of the week so far with temps approaching the mid to upper 90s for the eastern NC Piedmont, including Charlotte. With the moisture returning, this also increases the heat index values as well. Current trends have heat indices of 100-103 on Saturday for areas along and east of I-77. On Sunday, these higher heat indices are more spread out along and south of I-85. As the ridge moves eastward to start next week, long range guidance continues to signal for 100+ heat indices in some locations east of the mountains through mid next week. Though the exact values may change a bit, confidence is increasing on triple digit heat indices. The bottom line is it's about to get hot and proper precautions should be taken. This level of heat affects anyone without effective cooling or adequate hydration. If you are outdoors, be sure to properly hydrate, wear light clothing and take frequent breaks to avoid overheating.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

At KCLT and elsewhere: VFR conditions prevail through the TAF period. High pressure increases across the area keeping skies and vsby VFR. Winds are VRB at most sites and will remain VRB or even dip to calm overnight. Expect winds to lightly pickup late Thursday morning out of the SW for terminals outside the mountains. Mtn valley fog is possible, but with no rain today, not confident it will reach KAVL Thursday morning.

Outlook: Shower and thunderstorm chances and associated restrictions increase again Friday onward, especially over the NC mtns.

GSP WATCHES/WARNINGS/ADVISORIES

GA...None. NC...None. SC...None.