textproduct: Columbia

WHAT HAS CHANGED

Aviation discussion updated for the 06z TAF issuance.

KEY MESSAGES

- 1) Another round of light showers expected overnight.

- 2) Cold front leads to stronger winds Sunday with much colder temperatures Monday and Tuesday.

DISCUSSION

KEY MESSAGE #1: Another round of light showers expected overnight.

The cold front that brought showers and storms to the area has moved well south of the forecast area as of this evening, allowing the activity to push out of the area. Overnight, a piece of shortwave energy embedded within a larger scale trough is forecast to move over the area. As it does, shower chances return to the region. This activity is expected to be generally light and move out of the Midlands and CSRA by Sunday morning.

KEY MESSAGE #2: Cold front leads to stronger winds Sunday with much colder temperatures Monday and Tuesday.

Strong cold front will usher in a much drier and colder air mass into the area. Sunday winds increase with a strengthening pressure gradient and strong northwest flow with cold advection leading to temperatures dropping through much of the afternoon. NAEFS mean indicates 850mb winds will be above the 90th percentile with wind gusts between 30 to 40 mph likely (greater than 50 percent probability in blended guidance). A Lake Wind Advisory will likely be needed but will hold off for now with strongest winds likely after 1 pm Sunday (over 24 hours away). Strong agreement among models of the strength of the cold air mass that shifts into the area early next week with limited spread in the 500 mb heights, which are generally favored to be 2 to 3 standard deviations below normal. Blended guidance as a result indicates a tight spread in temperatures for Monday and Tuesday with high probability of lows dropping into the 20s Monday morning and Tuesday morning. While the frost/freeze program has not begun yet, with the recent warmup, any plants that have begun to bloom and are sensitive will likely need to be protected each morning.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

Mix of MVFR-LIFR restrictions overnight as showers linger across the region.

The stalled front continues to produce showers, low cigs, and reduced vsby across the TAF sites early Sunday. Generally the heaviest showers will continues to work through AGS-DNL-OGB through ~12z, with periods of LIFR-IFR conditions likely; CAE and CUB are generally staying MVFR-VFR, just north of these showers. After 12z, the front will push through and steadily start to clear low level moisture out with improving cigs and vsby and precip chances quickly decreasing. Gusty winds will then be the main story with northwest winds strengthening to over 20 knots with gusts over 30 knots for the afternoon and evening. Winds slightly decrease overnight into Monday, but sustained 15 knots with gusts over 20 knots still expected into Monday morning.

EXTENDED AVIATION OUTLOOK...Drier air continues to move into the region on Monday with gusty northwest winds of 25 kts possible. No notable periods of restrictions then expected through mid-week.

CAE WATCHES/WARNINGS/ADVISORIES

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