textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Updated for aviation.

KEY MESSAGES

1. The risk for severe storms will remain on Sunday across parts of the area. 2. The Heat Advisory is no longer in effect for this afternoon, but expect another day of above normal temperatures on Sunday. Make sure to stay hydrated and take frequent breaks in the shade or air conditioning.

DISCUSSION

Key message 1: The risk for severe storms will remain on Sunday across parts of the area.

The threat for more severe storms continues to creep upward on Sunday, even though the main front will have already moved through. A low level easterly flow will help to force the development of new storms and we retain some decent low level moisture. Slightly cooler air aloft may steepen the lapse rates in the afternoon, allowing for robust storms to develop in an environment that has 2500-3500 J/kg of sfc-based CAPE and marginal effective shear. There might not be as much potential for organization, but a decent potential for damaging wind gusts.

Drier conditions should return for much of next week as an upper anticylcone builds across the region. Another cold front may bring rain chances back Friday.

Key message 2: The Heat Advisory is no longer in effect for this afternoon, but expect another day of above normal temperatures on Sunday. Make sure to stay hydrated and take frequent breaks in the shade or air conditioning.

With rain-cooled air in the wake of the storms, temperatures have dropped into the 70s and 80s. Have canceled the Heat Advisory.

A cold front is still expected to drop southward across the region tonight. Extensive clouds and showers/thunderstorms will develop on Sunday in the easterly flow behind the front, so while temperatures especially in the Upper Savannah will still be above-normal with heat indices over 100, a good chunk of the area will see highs several degrees cooler than what we had this afternoon. Monday will be the coolest day, possibly below normal if the clouds hang on. A slight warming trend for the second half of the week as the air mass modifies and pattern becomes progressive once again, with the mid- level anticyclone returning overhead on Wednesday. Fortunately, it gets pushed off to the east with another broad upper trof moving past late in the week, which short-circuits the warmup.

AVIATION /00Z SUNDAY THROUGH THURSDAY/

At KCLT and elsewhere: VFR this evening and into the overnight hours in the wake of this afternoon's TSRA. Expect overnight restrictions in the vicinity of KAVL and have kept IFR restrictions at the terminal, but confidence is moderate as the lower cigs/vsby may be further down the valley. Expect another round of afternoon TSRA and have kept PROB30 through the end of the period, with lingering VCSH for KCLT in the out periods. Expect widespread restrictions to develop during those outperiods and have introduced MVFR cigs at KCLT. Winds VFR overnight, trending N to NE, but will pick up out of the ENE during the day Sunday.

Outlook: Restrictions and possibly SHRA may linger into the day on Monday. Drier conditions return by Monday night, lingering through mid-week.

GSP WATCHES/WARNINGS/ADVISORIES

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