textproduct: Columbia

WHAT HAS CHANGED

None for Key Messages. Expected rainfall amounts through the week remain relatively steady however the chance for rain this weekend has increased. Update aviation discussion for 00z TAFs.

KEY MESSAGES

- 1. Showers and thunderstorms possible mid-week.

- 2. Rainfall chances for this weekend are increasing.

DISCUSSION

Key Message 1: Showers and thunderstorms possible mid-week.

Rain chances will trend upward as we head into the middle of the week. While there could be a few showers possible on Tuesday, coverage is expected to increase Tuesday night into Wednesday morning as a cold front approaches and moves through the region. At this point, the better chances for precipitation on Tuesday should should be limited and confined to the western and northern Midlands.

As the cold front moves in, moderate wind shear coupled with sufficient instability hints at the potential for low-end storm organization, with an overall decent chance of rainfall through Wednesday night. While the overall severe threat remains low, it cannot be completely ruled out. Rainfall amounts of a quarter of an inch to half an inch are looking more likely, but recent model guidance has trended lower with QPF totals. Additional shortwave energy moving through later in the week will maintain at least slight chances for precipitation beyond the frontal passage.

Key Message 2: Rainfall chances for this weekend are increasing

Ensemble cluster analysis shows that broad troughing is favored over the eastern half of the US by late week and into the weekend. The NAEFS shows PWAT values approaching the 90th percentile of climatology with IVT near the 97th percentile. This supports a high chance to likely PoPs from Friday night through Saturday with the potential for a low pressure system to move across the Southeast. While there remains a large spread in model guidance for the time period, there is potential to see widespread rainfall for this event. Although we are too far out to get an accurate determination of rain amounts, we should see confidence forecast amounts increase as we move through the week.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

Generally VFR conditions through the TAF period, but low chances for restrictions late in the period.

Clear skies have brought us to this point in the evening. This afternoon was genuinely beautiful, with sunny skies following the morning stratus at all sites. Looking for mostly clear skies until late tonight as dry air and high pressure shift off to the east. By Tuesday morning, moisture will begin to work its way back in ahead of an approaching front, with some mid-level clouds likely to overspread the region associated with decaying showers/storms. Some MVFR ceilings are possible with this but generally thinking VFR cigs will be what ends up happening. Clouds will likely hang around into Tuesday afternoon, with winds shifting out of the southwest between 5 and 10 knots. Overall, a low impact TAF period is expected.

EXTENDED AVIATION OUTLOOK...Periods of restrictions are possible into the mid to late week with a more unsettled pattern continuing.

CAE WATCHES/WARNINGS/ADVISORIES

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