textproduct: Columbia

WHAT HAS CHANGED

Minimal change to Key Messages. Aviation discussion updated for 18Z TAF.

KEY MESSAGES

- 1. A typical summer pattern expected this week with increasing moisture and warming temperatures during the mid to late week period.

DISCUSSION

Key Message 1: A typical summer pattern expected this week with increasing moisture and warming temperatures during the mid to late week period.

For today and Tuesday, the surface ridging will shift far enough east to allow deeper moisture to push into the area. For this afternoon and evening, the primary plume of 1.75"+ PWATs will stay mostly across Georgia. Modeled soundings suggest that a stout capping inversion will limit convective chances across much of the Midlands, so PoPs have been lowered there, and many locations in the eastern half of the forecast area are likely to remain dry. The upper level ridge axis is also passing through the forecast area, further limiting convective development in our eastern FA. Having said that, showers are starting to develop in the CSRA and scattered showers along with isolated thunderstorms are possible there through this evening though widespread severe weather is not expected.

The plume of higher PWAT's shifts east by Tuesday and yields higher rain chances across the entire area. Scattered daytime showers and thunderstorms are then expected each day through the end of the week with a fairly typically summer pattern in place. With the ridge in our vicinity, significant rainfall is unlikely. While PWAT's should climb above 1.75", QPF totals across all guidance is generally only 0.25-0.75" with some isolated higher amounts in areas that see repeated rounds of thunderstorms. The combination of heat and humidity could result in our first days of heat index values at or above 100 degrees on Thursday and Friday, though still below heat product criteria.

AVIATION /18Z MONDAY THROUGH SATURDAY/

Isolated showers and storms this afternoon with mainly VFR conditions through the TAF period. Brief restrictions possible tonight into Tuesday morning.

Light southerly to southwesterly winds between 3-5 kts are developing this afternoon along with a shallow cumulus field. There have already been a couple showers near AGS/DNL but these have been nearly stationary and have collapsed quickly. The remainder of this afternoon could see a couple more isolated showers or storms, favoring AGS/DNL, though even here confidence in impacts is low. Any of this activity diminishes this evening with lingering mid and high level clouds as winds become light and variable to calm. This cloud cover is expected to continue most of the overnight period, but there is some indication in LAMP and HREF guidance that abundant low level moisture could bring brief periods of fog and/or stratus if any clearing occurs. Confidence in restrictions developing is low, but at this time fog prone AGS seems the most likely to have at least periodic MVFR vsby restrictions early Tuesday morning. A cumulus deck should develop through the late morning and into the afternoon with southerly winds picking up to around 5-7 kts. Scattered showers and storms could be possible just after this TAF period.

EXTENDED AVIATION OUTLOOK...Deeper moisture remains in place through the week leading to scattered, mainly diurnal, showers and thunderstorms.

CAE WATCHES/WARNINGS/ADVISORIES

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