textproduct: Columbia

SYNOPSIS

Cold front passes through tonight with isolated to scattered showers possible and continuing breezy winds. A much colder air mass builds in on Sunday with below normal temperatures and continued breezy conditions. Near to below normal temperatures will then prevail through much of next week.

NEAR TERM /UNTIL 6 AM SUNDAY MORNING/

Key message(s):

- Lake Wind Advisory continues into Sunday.

- Strong cold front pushes through the area later tonight, bringing isolated to scattered showers.

A robust cutoff low is seen currently over Wisconsin in WV imagery, sinking toward the southeast and driving surface low pressure placed in the upper Great Lakes region. The surface cold front from this system is gradually nearing the upstate of GA/SC, and is expected to pass through the FA overnight tonight. The strong 40-50 kt LLJ and upper dynamics continue drift toward the northeast and thus weaker moisture convergence has been seen over the area with PWAT's currently near 1.3-1.5". A 30-35 kt LLJ will remain in place through the frontal passage and thus isolated to scattered showers remain possible mainly before 06-08z with the front then passing through the FA. Overnight, the LLJ and fairly tight pressure gradient should keep surface winds elevated, especially over area lakes as colder/drier air gets ushered in behind the front. Due to this, the Lake Wind Advisory remains in effect overnight and into Sunday. Strong CAA begins to push in behind the front early Sunday, bringing a gradient in overnight lows ranging from the mid 40s in the northwest to the mid 50s the southeast.

SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/

Key message(s):

- Gusty winds behind the cold front Sunday with gusts up to 40 mph possible.

- Below average temperatures expected.

Sunday morning guidance consensus puts the cold front in the Coastal Plain with rapidly drier and cooler air filtering into the forecast area. It is likely that the high temperature for Sunday will be reached early in the day with temperatures either remaining steady of falling a bit into the afternoon. Noticeably cooler with temperatures 20 to 25 degrees lower during the day. While early Sunday morning there may be a lull in winds, another strong, around 40 knot low level jet will push into the area. This will be notable as with temperatures cooling rapidly aloft with an upper trough shifting over the area, mixing will become deeper with gusty winds expected at the surface by mid to late morning, continuing into the evening. HREF indicates a high probability of wind gusts exceeding 35 mph (~60-70%) with max gusts around 40 mph possible. The Lake Wind Advisory as a result will continue through Sunday afternoon as a result. Potential for fire weather concerns with drying fuels and subsequent shifts will evaluate the potential for fire weather products Sunday. The 850mb jet is expected to move out of the area Sunday night with winds decreasing. While blended guidance favors lows dropping into the mid to upper 20s, there is a bit of a skew towards lower values as there is a potential for favorable radiational cooling in the predawn hours as the winds drop off.

High pressure expected to ridge into the forecast area Monday with much cooler conditions. Blended guidance indicates about a 40-50% chance for temperatures to rise above 50F in what will be the coolest day of this year (which yes is only 11 days). Mostly sunny skies and light winds expected with high pressure in place while overnight lows likely drop into the 20s once again.

LONG TERM /TUESDAY THROUGH SATURDAY/

Key message(s):

- Temperatures moderate through mid week.

- A strong front will bring colder conditions for the end of the week and precip chances.

High pressure over the area Tuesday with the air mass moderating each day, near seasonal average. A bit of a moisture increase possible late Wednesday as a surface trough may develop near the coast. Significant uncertainty remains regarding the forecast for the second half of the week. Confidence is high that a strong upper trough will deepen over the eastern CONUS with the NAEFS mean indicating 500mb heights by Thursday will drop to below the 2.5 percentile. This will lead to a colder air mass over the area for the end of the week. There remains uncertainty as to the progression of this trough with some models leading to a slower progression which may allow for additional moisture to move over the region and chances for precipitation. For now, blended guidance keeps this at slight chance which seems reasonable for now until model guidance converges more on a solution.

AVIATION /00Z SUNDAY THROUGH THURSDAY/

Some periods of MVFR restrictions overnight due to lowering cigs, otherwise VFR on Sunday.

A cold front will gradually approach from the west overnight, brining lowering ceilings and some scattered light patches of rain. I don't expect conditions to be any worse than MVFR as cigs should stay above 1K feet and the rain will be light enough to allow vsbys to stay 5 miles or more.

There will be a period during the late evening and overnight where there will be some wind shear, but it is not expected to get high enough to mention in the TAFs. It may still be a bit bumpy, though.

On Sunday, the main story will be the wind. The wind will be gradually veering to the northwest during the day, and a reasonably strong low level jet will able to mix down in gusts in the 30 knot range, possibly stronger.

EXTENDED AVIATION OUTLOOK...No significant aviation concerns through the first half of the week.

CAE WATCHES/WARNINGS/ADVISORIES

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