textproduct: Columbia

WHAT HAS CHANGED

Confidence increasing in potential for frost/freeze this weekend. Aviation discussion updated for the 18z TAF issuance.

KEY MESSAGES

- 1. Seasonable conditions this week with a front ushering in a colder air mass for the end of the week and into the weekend.

DISCUSSION

Key Message 1: Seasonable conditions this week with a front ushering in a colder air mass for the end of the week and into the weekend.

High pressure continues to ridge over the forecast area expected to shift offshore by mid-week. Seasonable to slightly above average temperatures expected with blended guidance showing a limited spread, especially as it pertains to high temperatures this week, favoring highs generally in the mid-70s. Low temperatures show a bit more of a spread as strong radiational cooling is favored with light winds and clear skies so have slightly lowered temps overnight from the blend. Lows expected to gradually warm into Thursday morning as the front approaches and winds increase out of the southwest with increasing cloud coverage.

Ensemble means continue to converge on the strength and timing of the frontal passage through the area, expected Thursday leading to breezy winds which may approach Lake Wind Advisory criteria and potential for scattered showers, although moisture remains marginal with ensemble PWAT means around an inch. As a result, any showers not expected to result in significant rainfall amounts, especially with a relatively progressive front. The more notable change will be the air mass behind the front leading to much colder temperatures. GEFS and EC ensemble means indicate by this weekend 850mb temperatures with be near 10C below average. Blended probabilities indicate probabilities exceeding 50 percent of minimum temperatures below 35F Saturday through Monday mornings. Frost and freeze products may be needed this weekend as a result.

AVIATION /18Z MONDAY THROUGH SATURDAY/

Generally VFR conditions expected through the period.

High pressure will continue to build over the area through tonight providing dry and fair weather. Generally light winds with variable direction through the afternoon less than 5 knots before going calm overnight. Drier air and lower dewpoints should lend to lower probabilities of fog tonight but cannot rule out some river valley fog once again. Will not include in this forecast but could be some brief vsby restrictions at fog prone locations AGS/OGB. Winds will be slow to pick up on Tuesday but should become a bit more southerly at 5 knots or less after 15z.

EXTENDED AVIATION OUTLOOK...Dry air will likely prevent widespread restrictions through the extended with moisture increasing ahead of an approaching frontal boundary on Thursday.

CAE WATCHES/WARNINGS/ADVISORIES

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