textproduct: Columbia

WHAT HAS CHANGED

No major forecast changes this evening.

KEY MESSAGES

- 1) Lows tonight in the low to mid 20s.

- 2) Cold front approaches mid-week leading to breezy winds and chances for rain.

DISCUSSION

KEY MESSAGE #1: Lows tonight in the low to mid 20s.

High pressure will continue to shift into the southeastern US tonight. With a relaxing pressure gradient, weakening winds will give way to a favorable radiational cooling environment. The blended guidance distribution remains tightly clustered in the low to mid-20s, and MOS guidance further supports these numbers. Our local radiation scheme tends to favor the lower end of this distribution, but with the high not expected to be directly over the area, ideal radiational conditions may not be observed. Generally expect lows in the low to mid 20s, with some sheltered locations likely dipping into the teens, although once again expected to stay above cold weather advisory criteria. Any cold-sensitive vegetation could be damaged after last week's warm up.

KEY MESSAGE #2: Cold front approaches mid-week leading to breezy winds and chances for rain.

High pressure shifting offshore will lead to warming into the second half of the week with warm advection strengthening. Breezy winds expected Wednesday and Thursday with the NAEFS mean indicating 850mb winds above the 90th percentile across the forecast area, although forecast soundings show mixing heights relatively limited with a warm nose aloft. Increasing moisture with mean PWAT values from the GEFS and ECMWF ensembles nearing 200 percent of normal by late week. Some uncertainty among model guidance as to how deep an upper shortwave digs and as a result, how quickly this front moves through the area. Overall, this will likely lead to more beneficial rain for the area but timing remains a bit uncertain. Most guidance shows little to no instability ahead of the front so the threat of severe weather is low.

AVIATION /01Z TUESDAY THROUGH SATURDAY/

VFR conditions continue with lighter winds this TAF period.

Northwesterly winds continue to gust to 20-23 kts this evening but over the next couple of hours, these gusts should subside under mostly clear skies. Winds become light tonight, slowing shifting from the northwest toward the west. FEW to SCT cirrus may start moving into the region after daybreak Tuesday, but VFR conditions continue as high pressure builds in. 5-8 kt winds gradually shift from the west toward the southwest through the day, as cirrus coverage is expected to increase at the end of the TAF period.

EXTENDED AVIATION OUTLOOK...VFR conditions likely continue through at least Thursday. The next system may bring rain chances and restrictions late Thursday night and into Friday.

CAE WATCHES/WARNINGS/ADVISORIES

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