textproduct: Columbia

WHAT HAS CHANGED

Early morning showers and storms should diminish over the next few hours. Heat and humidity continue, with diurnal chances for showers/thunderstorms this afternoon and evening. Aviation discussion updated for 12z TAFs.

KEY MESSAGES

- 1. Diurnal showers and storms each day through the period.

DISCUSSION

- 1. Diurnal showers and storms each day through the period.

Rounds of showers and thunderstorms continue to move through the area from the west along remnant outflow boundaries. However, convection has started to weaken, especially as it approaches the I-20 corridor. Any lingering activity should dissipate into the early morning hours.

Little change has been made in the overall forecast. The weak upper level low that has been spinning over the southern Appalachians is finally being absorbed into a digging longwave trough extending south from the Great Lakes. In its wake, guidance remains in good agreement that a low-amplitude, seasonably strong ridge centered just to our south will build in by the weekend. Deep-layer southwesterly flow will maintain elevated PWATs through the end of the week. A classic summertime pattern will persist as 500mb heights climb to around the 90th percentile for early August. Highs will remain in the low to mid 90s with daily afternoon and evening showers/thunderstorms. With PWATs generally between 1.8-2", expect typical summertime convection. While a few stronger storms cannot be ruled out, widespread severe weather is not expected. However, efficient rainfall rates and slow storm motions may result in localized flash flooding.

AVIATION /12Z THURSDAY THROUGH MONDAY/

Ceiling and visibility restrictions possible once again through sunrise this morning. Otherwise expecting VFR conditions to be likely outside of isolated storms.

Showers have finally dissipated this morning, with only some left over mid and upper level cloudiness remaining around sunrise. Although a brief mvfr restriction can not be completely ruled out through 14z, expect enough cloudiness to remain to keep conditions vfr at all locations.

For much of the daytime hours after 14z, ceilings should continue to be vfr, with cumulus returning for most of the day. Much like the past several days, similar coverage of isolated afternoon and evening showers/thunderstorms is expected to develop. Current probabilities support keeping the PROB30 group at least into the evening hours. After showers dissipate tonight, winds will go light to calm, and with lingering low- level moisture can not rule out a return of mvfr or lower restrictions. Confidence is somewhat on the lower side right now, so will only start lowering visibilities ever so slightly to low end vfr towards midnight. Later issuances could end up trending into mvfr late tonight.

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

CAE WATCHES/WARNINGS/ADVISORIES

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