textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

The chance for more widespread showers and thunderstorms has increased for early next week.

KEY MESSAGES

1. Mainly diurnal convection and above-normal temperatures are expected thru the weekend.

DISCUSSION

Key message 1: Mainly diurnal convection and above-normal temperatures are expected thru the weekend.

The tail end of an embedded upper shortwave will pass just to our north and then off the Atlantic Coast this afternoon/evening. This feature combined with a weak boundary from a dissipated MCS will help provide forcing for convection to develop across our area this afternoon/evening. Instability has been trending upwards, but shear remains minimal across our area. We could see a few strong to severe storms before the day is over, but that's about it. Isolated heavy downpours are also possible, but they should be more limited than what we saw yesterday (Tuesday).

Otherwise, an upper ridge builds over the area thru Friday before a series of upper shortwaves brings more zonal flow aloft for the weekend, with a broad upper trof developing early next week. This will allow for diurnal convection Thurs thru the weekend, favoring the mtns each day due to the ridge limiting instability and creating higher LFC's outside the mtns. More widespread convection is likely across our area early next week with the height falls and shortwave activity. We can also expect above-normal temperatures across our area thru the weekend, with Friday expected to be the warmest day. At present, the probability of highs above 90 degrees outside of the mtns is high Thurs thru Sunday. The probability of highs above 95 degrees is lower for our area and more likely to our east and south. This still produces heat index values near 100 degrees for Thurs, and up to 103 degrees over our southern zones on Friday. Temperatures then steadily fall to near-normal early next week as heights fall with the approach of the upper trof.

AVIATION /19Z WEDNESDAY THROUGH MONDAY/

At KCLT and elsewhere: Over the past few hrs, sct convection has developed mostly over the NC mtns, with some activity also over the SC Upstate and southern NC Piedmont. Have handled this with PROB30s for TSRA until roughly 24z at most terminals, and a TEMPO for TSRA at KAVL from 18 to 22z owing to the better coverage over the mtns. Fog and low stratus will likely return overnight at KAVL and KHKY, with a decent chance at KAND as well. It's less likely at KGSP, KGMU, and KCLT, but still possible with light winds and dewpts remaining elevated. Any restrictions should burn off/dissi- pate by late morning. Otherwise, winds will remain SWLY this aftn/ evening and weaken tonight. Winds at KAVL and KHKY will likely go calm overnight. Outside of the mtns, winds pick up from the SW again tomorrow. Winds at KAVL will toggle around to N/NW late tomorrow morning.

Outlook: Diurnal convection and associated restrictions are expected into the weekend. Mtn valley fog and low stratus will be possible each morning.

GSP WATCHES/WARNINGS/ADVISORIES

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