textproduct: Greenville-Spartanburg

WHAT HAS CHANGED

The forecast was updated to reflect the recent 00Z TAF update.

KEY MESSAGES

1. Above average rain chances and below normal temperatures continue through much of the week. A low-end hydro threat may evolve by mid-week, but confidence is low at this time.

DISCUSSION

Key message 1: Above average rain chances and below normal temperatures continue through much of the week. A low-end hydro threat may evolve by mid-week, but confidence is low at this time.

Recent water vapor imagery is indicative of a closed circulation beginning to develop just to the southwest of the forecast area, over north-central Georgia. In response, an LLJ continues to advect deep moisture into the Carolinas...mainly to our east, however. The low terrain remains essentially clear of convection, with the window for initiation rapidly waning; only a few insignificant showers are ongoing across the NC mountains.

Model guidance continues to feature the formation of a closed low overnight tonight; that closed low will remain in place through mid-week. With the added synoptic forcing from this feature and anomalously high PWAT values (1.5-2.0", at or above the 90th percentile of climatology at both GSO and FFC), expect higher-than-normal convective coverage each day throughout the week, mainly during the typical diurnal max and with some potential for convection to linger later into the evening than usual.

By Wednesday through the end of the workweek, a digging longwave upper trough is noted in lo-res guidance across the northern/central Great Plains, and seems likely to help break down the upper low in the Southeast. However, weak upper troughiness will remain, resulting in higher-than-normal diurnal PoPs through the end of the workweek and into the upcoming weekend. Repeat days of this activity will result in a slowly-increasing risk of localized flash flooding, especially in locations that receive multiple rounds of heavy rainfall or training thunderstorms over a short period of time. Also can't rule out an isolated strong to severe thunderstorm or two each afternoon, with locally damaging wind gusts as the primary threat, but the environment is not conducive for organized convection or widespread severe weather throughout the week. Enhanced PoPs and cloud cover will allow for high temperatures to remain between normal and/or a category below normal through much of the forecast period.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

At KCLT and elsewhere: VFR conditions across the area this afternoon with convection mostly confined to the NC mountains. A plume of moisture to our south and east never quite made it into the area today, and as a result, showers and storms have stayed out of the Upstate and Piedmont zones. Winds will die down considerably tonight, giving way to another murky night. Expect at least IFR ceilings once again, while potential for patchy fog looks a bit diminished compared to previous nights, so not much in the way of vis restrictions advertised in the new TAFs. Stratus should steadily scatter out as it has the last few mornings...slowly but surely...with a return to VFR everywhere by early afternoon. Another round of diurnal showers and thunderstorms is likely Tuesday afternoon, with scattered to numerous coverage expected. Initiation may take place a little earlier Tuesday than it has the last couple of days, but still expect the peak in coverage and intensity to take place mid- to late-afternoon. Light NE winds will persist through the day Tuesday, except at KAVL where they'll be channeled more E/ESE by the French Broad Valley.

Outlook: Daily showers and thunderstorms, and associated flight restrictions, will continue through most of the week. Patchy fog and low stratus will be possible each morning, especially in the mountain valleys and anywhere that heavier rainfall has developed the previous evening.

GSP WATCHES/WARNINGS/ADVISORIES

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