textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

No significant changes to the forecast tonight.

Aviation forecast was updated to reflect the recent 06Z TAF issuance.

KEY MESSAGES

1. Heat Advisory still in effect for most of the Upstate and Charlotte Metro area this afternoon. Hot and humid weather continues through the weekend and into next week, with triple digit heat index values expected over the low terrain each afternoon. 2. Scattered diurnal showers and thunderstorms develop each afternoon through the weekend and into early next week. A couple strong to severe storms, as well as isolated nuisance flooding, will be possible each day.

DISCUSSION

Key message 1: Heat Advisory still in effect for most of the Upstate and Charlotte Metro area this afternoon. Hot and humid weather continues through the weekend and into next week, with triple digit heat index values expected over the low terrain each afternoon.

596dm anticyclone was analyzed over the LA/MS coast on recent water vapor imagery this morning. Expect stout upper ridging to remain in place through most of the forecast period, driving anomalously high temperatures. Dewpoint mixing will keep afternoon mugginess at bay, but will be limited by a lack of particularly dry air aloft; heat index values each afternoon through Monday are forecast to climb to 105 degrees are higher, with parts of the Savannah River Valley and southern SC Upstate climbing as high as 110 degrees.

A Heat Advisory remains in effect for Friday for most of the SC Upstate and the Charlotte Metro area, valid from noon through 8PM. Additional products may very well be necessary over the weekend.

Key message 2: Scattered diurnal showers and thunderstorms develop each afternoon through the weekend and into early next week. A couple strong to severe storms, as well as isolated nuisance flooding, will be possible each day.

Strong ridging over the central CONUS will continue to steer organized MCS tracks into the Carolinas over the weekend, resulting in scattered to widespread diurnal convection each afternoon. Saturday in particular may feature the approach of a weak frontal boundary from the north, further enhancing coverage (although the boundary is forecast to stall to our north and pull away again by Sunday) Saturday afternoon and evening. As a consequence, Saturday's parameter space looks marginally better than the rest of the weekend and early next week, with limited deep shear and synoptic forcing on the southern periphery of a z500 speed max streaming across the Mid-Atlantic. So, expect a little better severe risk on Saturday.

AVIATION /06Z FRIDAY THROUGH TUESDAY/

At KCLT and elsewhere: Dry conditions everywhere except for a couple very isolated showers crossing the Smokies tonight. Expect dry conditions at all the TAF sites overnight with VFR cloud cover into Friday morning. Could see some valley stratus and intermittent fog develop at KAVL before dawn, but confidence has actually decreased as cloud cover associated with a now-dissipated upstream MCS crosses the area. Any restrictions that develop will quickly scatter out after daybreak, giving way to another summer day, featuring afternoon cu and scattered afternoon showers and convection over much of the area (excluding KAND, where hi-res guidance is in good agreement that storms won't make it). WNW wind continues through the period.

Outlook: Scattered showers and thunderstorms possible each afternoon with flight restrictions possible for low stratus and fog each morning, especially in the mountain valleys.

GSP WATCHES/WARNINGS/ADVISORIES

GA...Heat Advisory from noon today to 8 PM EDT this evening for GAZ018-026-028-029. NC...Heat Advisory from noon today to 8 PM EDT this evening for NCZ070>072-082. SC...Heat Advisory from noon today to 8 PM EDT this evening for SCZ008>014-019-104>109.