textproduct: Columbia

SYNOPSIS

Slightly cooler temperatures are expected this afternoon, cooling further on Monday as high pressure passes to the north. Tuesday and Wednesday are warm with a chance of showers and perhaps a few thunderstorms with the passage of a cold front on 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 and cooler through tonight.

After some morning stratus across the east, drier air has finally pushed in from the north and brought mostly clear skies to the area. Those clear skies will last through tonight. Although there will be plenty of sun this afternoon, it will be cooler with this airmass. High temperatures still only in the low to possibly middle 70s. The very dry airmass will combine with nearly calm winds and those clear skies to bring some good radiational cooling conditions overnight. With dewpoints forecast to be in the lower to middle 40s by morning, expect overnight lows to be relatively close to those numbers too.

SHORT TERM /MONDAY THROUGH WEDNESDAY/

Key message(s):

- Continued dry and a bit cooler on Monday.

- Warmer Tuesday and Wednesday with a chance of showers and perhaps a few thunderstorms with the passage of a cold front on Wednesday.

The axis of an upper ridge will pass through the region on Monday while surface high pressure to the north moves offshore. After any patchy morning fog burns off, the day will begin mainly sunny with increasing high-level cloudiness as the day goes on. Winds around high pressure will be northeast shifting east around midday. As a result, forecast highs are slightly lower than today despite ridging aloft with values ranging from the upper 60s to mid-70s. PWATs increase quickly Monday night as the next storm system approaches allowing clouds to lower and thicken. This limits cooling somewhat with lows in the mid-40s to lower 50s.

The upper flow will be southwesterly on Tuesday and Wednesday as a trough moves from the Upper Great Plains into the Great Lakes region. The surface cyclone will move from around Minneapolis at daybreak Tuesday, across Lake Superior, and into Ontario by the end of the short term. This storm system will drag a cold front through the FA on Wednesday. Surface winds shift to the south on Tuesday and southwest on Wednesday ahead of the advancing cold front. Rain chances increase on Tuesday with rain most likely Tuesday night into Wednesday when a few thunderstorms will also be possible. While precipitation is in the forecast, forecast rainfall amounts are not high and are generally under an inch with this event. Daytime temperatures will be above normal both Tuesday and Wednesday with forecast highs in the 70s.

LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/

Key message(s):

- Very dry and much colder weather is expected for Thanksgiving and the remainder of the week.

A significant pattern change occurs during the extended as a much colder and very dry air mass filters in behind the cold front for Wednesday night and the remainder of Thanksgiving week. Temperatures Wednesday night fall into the mid-30s to lower 40s as skies clear out. Below normal temperatures are then expected Thursday through Saturday. The chance of rain is very low, less than 10 percent through the extended period.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

Mainly VFR conditions are expected through the 24hr forecast period.

Drier air moving in from the north has cleared skies out across the area. With very limited moisture the next 24 hours, skies should remain clear and vfr. The dry airmass should help to inhibit any fog formation at most locations, but as usual at ags/ogb can not completely rule out brief patchy ground fog from the nearby rivers at both sites. Winds this afternoon generally light and out of the northeast, becoming calm overnight.

EXTENDED AVIATION OUTLOOK...No significant aviation concerns expected through early next week. By mid-week, another approaching cold front Wednesday into Thursday could bring a return of restrictions.

CAE WATCHES/WARNINGS/ADVISORIES

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