textproduct: Columbia

WHAT HAS CHANGED

A line of showers and thunderstorms will move across the forecast area this afternoon into the early evening hours bringing the threat of heavy rainfall and localized flash flooding. Aviation discussion updated for 18z TAFs.

KEY MESSAGES

- 1. Rain and thunderstorm chances continue to end the weekend and are likely to continue through the upcoming week.

DISCUSSION

- 1. Rain and thunderstorm chances continue to end the weekend and are likely to continue through the upcoming week.

Midday satellite imagery shows the stubborn low clouds from this morning starting to break up across much of the forecast area, especially across the southern half of the region. Meanwhile, a line of showers and thunderstorms are moving into the FA from the west. The clearing skies should help to destabilize the atmosphere, promoting convective development. Another active afternoon is likely on the horizon as this line slowly moves east across the CWA. PWATs remain in excess of 2 inches, therefore the main threat this afternoon will once again be from heavy rainfall and localized flash flooding, especially the areas that saw between 2 and 5 inches of rain yesterday. Any robust thunderstorm that develops could also produce damaging wind gusts but with lower CAPE and DCAPE values in place, this threat is lower today and may be limited to locations that have already broken out of the overcast.

After today, a closed low is forecast to break off of the main upper trough meandering over the Tennessee Valley for several days. As such, daily chances (30 to 70 percent) for showers and thunderstorms continue through much of the week ahead. Temperatures during the next seven days are forecast to be near to slightly below seasonal values.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

VFR conditions with another round of showers and storms bringing periodic restrictions through this evening.

VFR to begin the TAF period. SCT-NUM SHRA/TSRA will develop this afternoon and persist into the evening. Little airmass change has occurred, so expect heavy rain and therefore VSBY restrictions along with periods of lower CIGS. Winds should be a bit stronger today and from the south around 10 knots. A few stronger gusts potentially up to 25 kts are possible in the strongest TSRA. Another night of stratus redevelopment should occur, with CIGS falling to MVFR/IFR into Monday morning. Most precip should shift toward the east for Monday with less coverage at the terminals.

EXTENDED AVIATION OUTLOOK...Periodic rain and restrictions continue early this week.

CAE WATCHES/WARNINGS/ADVISORIES

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