textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

Rain amounts trend slightly drier for today and Tuesday.

KEY MESSAGES

1. Scattered showers and thunderstorms through this evening with a marginal risk for severe storms, mainly across the southern half of the area. 2. Dry conditions return with a warming trend through the weekend.

DISCUSSION

Key message 1: Scattered showers and thunderstorms through this evening with a marginal risk for severe storms, mainly across the southern half of the area.

A trough over the eastern portion of the country amplifies southward today and brings a cold front through on Tuesday. Ahead of that, a NW upper flow regime sets up the MCS maker and brings the chance for scattered showers and thunderstorms through tonight. The Storm Prediction Center has a marginal risk (1 of 5) for severe weather today. Out west, an MCS is already ongoing, but is expected to dive south of the area. Meanwhile, ahead of it, a series of shortwaves cross the CWA, adding an area of lift for storms. Model soundings for the afternoon show modest amounts of instability developing with about 1000-1500 J/kg of sbCAPE and 30-35kts of bulk shear. Given the anticipated environment, cannot rule out a few storms becoming strong or severe with strong winds and small hail being the main threats. Brief periods of heavy rainfall are also possible with any storm that develops. However, storms should be moving out quickly, reducing flood concerns. The main locations with the higher chances for showers and thunderstorms becoming severe are along and west of I-26 in NC/SC and into northeast GA.

For Tuesday, guidance depicts another round of showers ahead of the cold front pushing through. Coverage looks to be less widespread and rather benign. Highest chances are for the mountains (30-45%), but there is still a slight chance (15-30%) for locations along and west of I-26. QPF response looks to be minimal, with most locations receiving less than 0.10" in totals. There could be a slight uptick if a shower produces more rain in an isolated location. Temps look to be below normal for Tuesday as well.

Key message 2: Dry conditions return with a warming trend through the weekend.

Once the frontal boundary passes, much drier air and calmer weather conditions ensue. High pressure is ushered in as a ridge moves over the southeast and remains in place through the weekend. These height rises toward the end of the week look to increase daily temps to normal for June. Moisture starts to return as well after mid-week and this increases dewpoints. However, not foreseeing any heat index issues at this time. Long range guidance starts to signal for rain chances returning toward the beginning of next week, but confidence this far out is very low.

AVIATION /18Z MONDAY THROUGH SATURDAY/

At KCLT and elsewhere: Conditions should prevail VFR for most of the TAF period, with some brief restrictions for TSRA through the evening and a return at a few sites of MVFR Tuesday morning. For this afternoon, showers and thunderstorm chances increase at all terminals. TEMPOs for KCLT/KGSP/KAND/KGMU should suffice for the first round of TSRA between 18z-22z. Another round could occur after 22z through 04z, but certainty on location is lower. For this, VCTS for those storms at KCLT/KGSP. There may be a lingering SHRA after 04z, but confidence is low. Brief vsby restrictions possible with any TSRA. Otherwise, vsby remains VFR. As for cigs, lower stratus returns for a few terminals ahead of drier air moving in Tuesday. Expect brief MVFR Tuesday morning and low-end gusts of 15-20kts after 12z for terminals east of the mountains. Wind direction should remain N/NE for the duration of the forecast.

Outlook: Showers possible again Tuesday afternoon. A drier pattern sets up by Wednesday and continues through the rest of the week.

GSP WATCHES/WARNINGS/ADVISORIES

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