textproduct: Columbia

WHAT HAS CHANGED

Scattered thunderstorms continue, with a low chance of severe downburst winds possible. Aviation discussion updated for 00z TAFs.

KEY MESSAGES

- 1. Thunderstorms expected each afternoon this week.

DISCUSSION

- 1. Thunderstorms expected each afternoon this week.

With deepest moisture to the east we will see scattered storms continue through the evening. The environment favors typical pulse convection with potential for an isolated severe storm. Despite lower PWAT values today, slow storm movement may support a localized threat of flash flooding. The main threat would be if storms develop over urban areas. After sunset, we should see convection diminish with just a few isolated showers or thunderstorms remaining overnight.

Beyond today, we are forecast to gradually see rising heights and rising afternoon highs through much of the period. Ensemble guidance is fairly confident in the 500 hPa height pattern & PWs through the period, with LREF members showing very little in the way of IQR spread through the end of the week for both features. While the trough is expected to fill and weaken quickly over the next couple of days, the presence of 1.8"-2.0" PWs should continue to favor daily thunderstorm activity. Convective temps look to be anywhere from 88F to 93F each day this week which is forecast to be reached fairly easily. So oppressive humidity, slightly above normal temps in the mid 90s, and diurnal thunderstorm activity is likely to be the norm by the second half of this week and into the weekend.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

VFR this afternoon with occasional restrictions due to showers/thunderstorms. CIG restrictions possible tonight, but lower confidence compared to the past few days.

Mostly VFR conditions across the region this evening as surface winds continue out of the southeast at 5-10 kts. Scattered showers and thunderstorms are currently moving across the central and eastern Midlands. Coverage for now continues to support PROB30 groups for thunderstorms into early this evening with activity diminishing a few hours after sunset. Stronger storms could produce heavy rain and brief restrictions along with gusty winds of 25-30 kts.

Models continue to be less aggressive compared to previous nights regarding restrictions. However, increased moisture still remains in place, so I've maintained TEMPO groups for another round of CIG/VSBY restrictions early Wednesday morning. These should dissipate after sunrise with scattered cumulus developing along with light south to southeast winds. Another day of diurnal showers and thunderstorms should develop in the afternoon with coverage supporting PROB30 groups, similar to previous days.

EXTENDED AVIATION OUTLOOK...Diurnal thunderstorms expected this week with early morning restrictions possible.

CAE WATCHES/WARNINGS/ADVISORIES

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