textproduct: Columbia

WHAT HAS CHANGED

Aviation forecast updated.

KEY MESSAGES

- 1) Breezy winds and increasing rain chances mid to late week.

DISCUSSION

KEY MESSAGE #1: Breezy winds and increasing rain chances for late Wednesday through Friday.

An approaching, mostly dry, front will strengthen southwest flow across the area Wednesday with some wind gusts over 30 mph likely starting Wednesday morning and into the evening. This front will then drag out and stall across North Carolina late Wednesday into Thursday. A diving shortwave and associated surface low will then slide across the southern US and produce some broad WAA and moisture advection over this stalled front. Rain chances will generally stay to our north until Thursday morning as the surface low and stalled front dips south, with widespread showers overspreading the area throughout Thursday and into Friday. This is a fairly good training setup for efficient heavy showers with deep flow parallel to the driving surface front, PWAT's to around 1.5", and saturated conditionally unstable profiles. The NAEFS and EC members have correspondingly increased probabilities for greater than 1.0" across the area through Saturday, now roughly 70% chance along with an increasing signal in the EC EFI. Like the EFI shows, the high end 90th percentile is now over 2.5" through late Saturday. The synoptic and mesoscale setup favors these high end amounts, but will likely only fall over a very narrow swath.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

VFR conditions will continue today along with breezy winds.

The KCAE VAD wind profile shows a 30 to 40 kt LLJ around 2 kft this morning. Surface winds have decreased to 5 kts or less so LLWS has been included until 14Z when winds should start picking up at the surface.

SW winds will pick up around 14Z today with gusts from 20 to 25 kts. A front will approach the region from the north and west today contributing to increasing moisture and gusty winds but rainfall is unlikely during the 24 hour TAF period. BKN cirrus are expected to remain in place through the day with some gradual lowering of the deck but VFR conditions remain likely. LLWS criteria may be met again tonight as another 30 to 40 kt low level jet sets up ahead of the front. Showers will likely hold off through 12Z Thursday but if the front is faster than expected there is a chance for a few showers or MVFR ceilings prior to 12Z. EXTENDED AVIATION OUTLOOK...Widespread restrictions and rain expected Thursday and Friday as a front moves through the area.

CAE WATCHES/WARNINGS/ADVISORIES

SC...Lake Wind Advisory until 7 PM EST this evening for SCZ016-018- 020>022-025>031-035-037-038-041-115-116-135>137. GA...Lake Wind Advisory until 7 PM EST this evening for GAZ040- 063>065-077.