textproduct: Columbia

SYNOPSIS

Warm weather continues into mid-week with a chance for showers and perhaps a few thunderstorms on Tuesday and Wednesday. A very dry and much colder air mass moves in behind the front for the remainder of Thanksgiving week.

NEAR TERM /THROUGH TONIGHT/

Key message(s):

- Dry weather continues with above normal temperatures

As a surface high drifts offshore and easterly, onshore flow develops we will see stratus and fog form in the Lowcountry and advect into the southern Midlands and CSRA. Conditions will improve through the early morning as fog and stratus lift.

With dry high pressure at the surface and ridging overhead the weather will remain quiet with no rain through the near term. Forecast highs will range from the upper 60s to mid-70s. Shallow moisture continues to increase overnight keeping lows in the mid-40s to lower 50s.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/

Key message(s):

- Scattered showers expected Tuesday and Wednesday as a front moves through the region.

The cutoff low in the southwestern CONUS will eject across the central US, driving a strong low pressure development into the Great Lakes Tuesday and Wednesday. This ejecting low will amplify the pattern with deep ridging developing for our area ahead of the associated surface front. Broad southwesterly flow Tuesday will steadily increase PWAT's and isentropic lift over the area and with temps pushing into the mid-upper 70's, some scattered showers are expected. The strongest height falls, upslope flow, and isentropic lift however will pull northwest of our area in the mountains and Upstate. So total precip is expected to be light Tuesday with guidance now fairly consistent in showing a general 0.1"-0.25"; some very weak instability will develop in the afternoon so a couple light thunderstorms are possible and could locally increase rain totals, especially in the western Midlands. As we move into Wednesday, the surface front will be approaching the area and a swath of strongest moisture advection will push through with PWAT's over 1.25"; some a period of elevated shower activity is likely Wednesday morning but still QPF totals less than 0.5" are expected. Precip chances then steadily decrease throughout Wednesday into the evening as the surface front pushes through, bringing notable dry advection into Thanksgiving.

LONG TERM /THURSDAY THROUGH SUNDAY/

Key message(s):

- A cold and extremely dry airmass will push into the region Thursday through Saturday.

Behind the front from Wednesday, an arctic airmass will dive down into region with strong northwesterly flow and well below average temps and dew points filling in. This will effectively arrive in two fronts, the initial on Thursday and a reinforcing front Friday. NAEFS and EC EFI show this airmass well with 5th percentile or lower for PWAT's, temps, and heights Thursday through Saturday. This will equate to high and low temps 10-15 degrees below average along with dew points falling to the lowest of the autumn so far. Ridging will build back in and temps start to moderate by late next weekend ahead of the next rain chances.

AVIATION /05Z MONDAY THROUGH FRIDAY/

Restrictions likely at OGB and AGS this morning.

Surface high pressure will shift offshore leading to stratus and fog developing near the coast and advecting into the southern Midlands and CSRA early this morning. Expect periods of MVFR or IFR ceilings and vsbys at OGB and AGS. DNL may also experience restrictions but confidence is lower due to the siting of the terminal. Restrictions will improve after 12Z with light, east winds from 5 to 7 knots through the afternoon becoming calm around sunset.

EXTENDED AVIATION OUTLOOK...The next chance of widespread restrictions will be late Tuesday into early Thursday morning as deep moisture returns to the area ahead of a front.

CAE WATCHES/WARNINGS/ADVISORIES

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