textproduct: Columbia

WHAT HAS CHANGED

An unsettled weather pattern returns through the week. Aviation discussion updated for 18z TAFs.

KEY MESSAGES

- 1. After a dry Monday, unsettled weather returns for the rest of the work week.

DISCUSSION

Key Message 1: After a dry Monday, unsettled weather returns for the rest of the work week. A cold front continues to sag southward today, bringing drier and cooler conditions to the region compared to the past several days. In the wake of the front, noticeably less humid air has filtered in with dewpoints this afternoon mixing out into the lower 60s. Even cooler thickness will push in from the north, and combined with increasing cloud cover, daytime highs are expected to be ~5 degrees below normal for tomorrow.

After today, unsettled weather is expected to return for the remainder of the week as the frontal boundary lingers across the southeast and multiple shortwaves move over the region. This pattern will help expand shower and thunderstorm coverage into the FA, particularly as a weak surface low attempts to develop along the stalled boundary Tuesday morning. The latest guidance trends keep the highest IVT transfer and PWATs generally remain south of the area for much of the week, keeping the highest PoPs in the southern portions of the forecast area and locations south. Periods of scattered showers and storms are expected Tuesday and Wednesday as a summer-like pattern returns. Instability appears relatively weak, so widespread severe weather is not anticipated at this time, but given the time of year, a strong storm is capable of producing gusty winds.

Looking further, most deterministic guidance remain in good agreement regarding a vigorous shortwave trough diving into the Upper Midwest while a weak tropical disturbance drifts across the western Gulf. The associated low is expected to lift into the northeast along the boundary, helping to maintain a stalled front across the Deep South. Temperatures should gradually warm back to near-normal by midweek, while increased moisture chances return after Thursday. Forecast confidence decreases late in the week as model solutions diverge on the evolution of the low in the Gulf as it tracks inland along the frontal zone across the Southeast. The ECMWF continues to depict a stronger and slower- moving system, while the GFS remains faster with the wave reaching the area by Thursday. Regardless, increasing rain chances appear likely late in the week as upper level winds will pull moisture from the system to the North and East. A heavy rainfall threat and isolated severe weather could be possible, but confidence remains too low for greater detail at this time. By the weekend, drier air should return as the upper trough shifts eastward.

AVIATION /18Z MONDAY THROUGH SATURDAY/

VFR conditions generally expected.

Drier air has moved over the terminals as a cold front moves through the region. This will limit any convection at the terminals with just some scattered cumulus continuing through the afternoon. Winds will remain out of the west with gusts to around 20 knots possible through the afternoon, becoming mostly light and variable tonight. Expect moisture to slowly return tomorrow with chances for showers favoring the southernmost terminals, although models show relatively high confidence of continued VFR conditions. Highest chances for thunderstorm activity will be after 18z so have left out the mention of tsra.

EXTENDED AVIATION OUTLOOK...Diurnally favored convection possible each afternoon mid week with possible morning fog/stratus bringing restrictions. Breezy conditions expected Thu/Fri.

CAE WATCHES/WARNINGS/ADVISORIES

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