textproduct: Columbia

WHAT HAS CHANGED

Update wording in Key Message #1 to remove discussion of early morning today.

KEY MESSAGES

- 1. Showers and thunderstorms are expected to continue this afternoon and evening, bringing potential for heavy rainfall and isolated flooding.

- 2. After a cold front on Monday, the pattern becomes more uncertain.

DISCUSSION

Key Message 1: Showers and thunderstorms are expected to continue this afternoon and evening, bringing potential for heavy rainfall and isolated flooding.

A shortwave trough continues to move through the Southeast today, bringing showers to the area, mainly in the PeeDee region at this time. The heaviest rain associated with these showers has remained just north of the forecast area. However, some brief rises in small streams in Lancaster and Chesterfield Counties can be anticipated over the next hour or two due to this heavier rainfall.

PWATs above the 90th percentile and stronger upper-level forcing later today, scattered showers and thunderstorms are expected to redevelop as the front hangs around through the day. As a result, periods of locally heavy rain will remain possible most of the day with a limited but continued threat of isolated flash flooding.

Key Message 2: After a cold front on Monday, the pattern becomes more uncertain.

An upper-level trough digging southward along the Eastern Seaboard is expected to push the stalled boundary back to our south on Sunday. Additional chances for showers are possible with cooler and direr air ushering in behind. Despite the frontal passage, poor lapse rates should limit instability and suppress most convection, with only slight Pops lingering near the CSRA, closest to the boundary.

Beyond that the forecast becomes uncertain. Most guidance indicates a brief period of drier weather Sunday followed by another round of rainfall on Monday ahead of a stronger cold front. High pressure will follow and bring in cooler and drier northerly flow to the region. Models begin to differ by midweek with some bringing in another chance for rain. However, a gradual warming trend is expected into the later part of the week, still below normal though. Moisture slowly returns as well bringing back the potential for diurnal convection potentially by Friday next week.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

Showers early with scattered storms possible this afternoon. Restrictions possible tonight.

Light showers have been passing over the terminals early this morning and are expected to continue through much of the morning associated with a shortwave before tapering off into the afternoon. Little in the way of restrictions associated with this activity, although there have been some low clouds at times, mainly over the Augusta terminals. VFR conditions are expected to return later this morning. Convection will likely develop this afternoon and while guidance does not indicate significant instability, there is enough to include a prob30 for thunderstorms with this TAF issuance. Tonight a cold front will move through the area and low level moisture will likely pool along it, leading to potential ceiling restrictions tonight, potentially impacting all the terminals.

EXTENDED AVIATION OUTLOOK...Unsettled weather should continue into early next week until drier air moves into the region mid-week.

CAE WATCHES/WARNINGS/ADVISORIES

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