textproduct: Columbia

WHAT HAS CHANGED

Aviation updated for 12z TAFs.

KEY MESSAGES

- 1. Well above average temps expected Sunday & Monday ahead of front that will bring some conditional thunderstorm potential.

- 2. After Monday, extended dry and seasonal weather expected with some increasing fire weather concerns.

DISCUSSION

KEY MESSAGE 1: Well above average temps expected Sunday & Monday ahead of front that will bring some conditional thunderstorm potential.

Broad ridging from the surface to aloft to our southwest will push temps into the upper 80's both Sunday and Monday. Breezy southwest winds up to 20-25 mph are expected Sunday with deep mixing and 850mb temps around 15 C and again early Monday. While not quite record highs, this will yield surface temps nearly 20 degree above average topping out around 90 F.

A southward sinking cold front will approach the area late Monday afternoon and bring some thunderstorm potential to the I-20 corridor and south; a marginal risk continues for these areas. Overall, this is a highly conditional severe setup with numerous factors that need line up spatially and temporally in order to see any severe threat. Instability ahead of the front will only be sufficient for a severe threat briefly in the afternoon as moisture convergence along the front is not terribly impressive; during peak heating HREF and EC-GFS generally produces a brief swath of 800-1200 ML CAPE mid-Monday afternoon. The mesoscale forcing from the front will be fairly strong given the thermal gradient but synoptically there is notable dry air above 700mb, so initiation will be instability dependent. So the best chance for the frontal forcing, initiation, and instability development to line up will be in the mid afternoon, generally south of I-20. Deep layer shear south of the front, along with high DCAPE, will allow for any deep convective storms that do development to pose a severe threat.

KEY MESSAGE 2: After Monday, extended dry and warming weather expected with some increasing fire weather concerns.

Longer term looks rather unremarkable with steadily warming temps and generally low rain chances through the end of the week behind the front. The front from Monday will bring cooler temps to the area and stall close enough that a few showers are possible in the CSRA Tuesday. Temps will then steadily climb from slightly below average Tuesday to well above average again by Friday.

Given the persistent low-level dry air and particularly following Monday's front, we are entering a period of increasing fire danger concerns given the lingering drought conditions. Winds speed out of the southwest will gust to around 20-25 mph Sunday and Monday, but the winds should weaken behind the front Monday into Tuesday. While winds will be lighter, RH's will fall below 30% Tuesday.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

VFR conditions expected through the 24hr forecast period.

Persistent northwesterly flow aloft continues to day in the wake of a passing shortwave this morning, keeping fair weather over the area today. Southwesterly flow ahead of the next frontal boundary will increase today with deep mixing expected as winds pick up to around 10 knots by 15z then a bit stronger this afternoon with gusts 20 to 25 knots. Mostly clear skies expected save for some passing thin cirrus. Wind gusts should subside with sunset but an increased pressure gradient and strong low level jet will keep winds up around 7 to 10 knots through the evening hours.

EXTENDED AVIATION OUTLOOK...A more significant cold front will move through on Monday, with a slightly better chance for restrictions. Overall, conditions will be most likely VFR for the next several days.

CAE WATCHES/WARNINGS/ADVISORIES

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