textproduct: Columbia

WHAT HAS CHANGED

Rain continues to spread into the region this morning. Aviation updated for 06Z TAFs.

KEY MESSAGES

- 1. Widespread rainfall through much of today.

- 2. Unsettled weather returns for the middle of next week.

DISCUSSION

Key Message 1: Widespread rainfall through much of today.

Deep moisture will continue to spread into the region this morning as PWAT values rise to 1-1.5 inches with the deepest moisture across the southern Midlands. Low pressure will develop along a frontal boundary to our south as a deepening trough pushes over the southeastern US. This will strengthen moisture advection over the forecast area and lead to widespread rainfall through mid-day when drier air will begin pushing in from the west. This will result in a steady, moderate rainfall event with totals expected to range from 0.5 to 1.25 inches, with isolated totals of 1.5-1.75 inches possible, especially across our southern counties. Rain will taper off this afternoon and evening. We cannot rule out a weak thunderstorm but instability, even elevated, is at a minimum.

Key Message 2: Unsettled weather returns for the middle of next week.

The next period of notable weather will be mid-week when a trough is expected to lift over the eastern US. The associated, trailing cold front may sag into the Southeast late Wednesday or Thursday. The NAEFS shows IVT near the 99th percentile of climatology and above normal atmospheric moisture. However as the stronger dynamics lift further north with the trough, we may see the convection along the front weaken with dryer westerly winds at the mid-levels accompanying the frontal passage. This typically leads to more scattered convection over our forecast area, suggesting NBM PoPs could be too high for the time period. Dry weather likely to return by late week and into the weekend.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

Periodic MVFR to IFR conditions into the afternoon before returning to VFR.

Widespread, mostly light, rainfall continues across the area at this time. However, a few breaks are starting to show up in the radar imagery. Expect rainfall to continue through about 20z-22z. Some of the latest guidance hints at the rain ending slightly before that. Ceilings have been bouncing between MVFR and low-end VFR, with a few periods of IFR at times. This trend should continue through the duration of the rainfall before VFR conditions return for the last half of the TAF period. Northerly winds are expected to increase to near 10 kts, with a few isolated gusts in the 15-20 kt range for much of the daytime hours. Winds diminish after 20-22z and become more variable for the remainder of the period.

EXTENDED AVIATION OUTLOOK...Drier conditions then are expected Sunday and into the early week. A midweek system brings a chance for restrictions once again.

CAE WATCHES/WARNINGS/ADVISORIES

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