textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Updated the aviation discussion.

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 /00Z THURSDAY THROUGH MONDAY/

At KCLT and elsewhere: VFR conditions prevail at most sites for this TAF issuance. Lingering SHRA and TSRA should continue to diminish overnight and leave mostly SKC. Given the moisture regime for the areas, KAVL and KHKY could see another round of FG/BR in the early hours. There wasn't as much rainfall in these locations but confidence is still high enough to keep the TEMPOs from 09z-12z for 1/2sm and 1sm at KAVL and KHKY respectively. Winds should also go calm overnight across the mountains sites and stay light, but SW elsewhere. After daybreak Thursday, a few -TSRA possible for the mtn terminals during the afternoon, but confidence is too low at KCLT to warrant any mention at this time.

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.