textproduct: Columbia

WHAT HAS CHANGED

Aviation Discussion updated for 00z TAF issuance.

KEY MESSAGES

- 1. Frost Advisory in effect tonight and a Freeze Watch is in effect late Saturday night into Sunday morning.

- 2. Below normal temperatures to persist through early next week, moderating by mid next week.

DISCUSSION

Key Message 1: Frost Advisory in effect tonight and a Freeze Watch is in effect late Saturday night into Sunday morning. The forecast for tonight remains on track. There is mid level cloud cover lingering over the FA this evening, but this is expected to scatter out over the coming 4-6 hours, allowing more efficient cooling to begin with persistent CAA pushing in. As has been discussed, the main inhibiter to overnight lows will be elevated surface winds around 5 kts. Despite this, lows into the mid 30s are still expected. Overall, conditions are expected to be conducive for patchy to scattered frost development tonight. Due to this, the Frost Advisory will go into effect at 3 AM, lasting until 8 AM.

The coldest conditions will be Saturday night into Sunday morning as the pressure gradient relaxes, winds remain light, and skies remain largely clear. While the NBM has trended a tick warmer in the past couple of runs, there remains a 40 to 90% chance of lows falling to or below freezing Sunday morning, which the greatest chances for the northern Midlands. Have kept with the Freeze Watch for the whole CWA for now but will reevaluate with the overnight forecast package for an upgrade to a Freeze Warning.

Key Message 2: Below normal temperatures to persist through early next week, moderating by mid next week.

With the surface high in place to our northwest and trough aloft, temperatures will remain 5 to 10 degrees below normal through Tuesday, with highs remaining in the upper 50s to mid 60s and lows in the 30s. Temperatures will begin to moderate toward normal as a mid-level ridge builds the eastern CONUS mid to late next week. A shortwave trough will deamplify as it translates east across the Southern US early to mid week, keeping any precip chances displaced to our south across the Gulf Coast into Florida.

AVIATION /00Z SATURDAY THROUGH WEDNESDAY/

VFR conditions expected through the period.

Northwest winds around 5-10 kts persist early this evening, but should decrease to less than 5 kts around 06z. SCT-BKN cloud bases at 5-6kft MSL will diminish overnight with only a few clouds or SKC much of Saturday. Fog not expected overnight with dry air and mixing at the surface. Northwest winds continue Saturday at 8-10 kts through the day.

EXTENDED AVIATION OUTLOOK...Dry air will likely prevent widespread restrictions through the extended.

CAE WATCHES/WARNINGS/ADVISORIES

SC...Frost Advisory from 3 AM to 8 AM EST Saturday for SCZ016-018- 020>022-025>031-035-037-038-041-115-116-135>137. Freeze Watch from late Saturday night through Sunday morning for SCZ016-018-020>022-025>031-035-037-038-041-115-116- 135>137. GA...Frost Advisory from 3 AM to 8 AM EST Saturday for GAZ040- 063>065-077. Freeze Watch from late Saturday night through Sunday morning for GAZ040-063>065-077.