textproduct: Columbia

SYNOPSIS

A much colder air mass builds in behind an exiting cold front, with chilly temperatures tonight. Near to below normal temperatures are expected during the next seven days. The chance of rain during the next week is low, less than 30 percent.

NEAR TERM /THROUGH TONIGHT/

Key message(s):

- Cold and very dry with below normal temperatures

Upper level trough axis has shifted off the coast with 500mb flow becoming more zonal across the forecast area. Surface high pressure centered over the lower MS Valley will build east into the region today with generally light northerly winds. Satellite imagery shows continued thin cirrus clouds traversing the southern half of the forecast area. Temperatures will be cooler than Sunday with 850mb temperature anomalies 3-5 degrees below normal and expect highs to be around 50 degrees. The high pressure ridge axis should be over the forecast area tonight with near calm winds and a very dry air mass in place supporting strong radiational cooling. Overnight lows should be in the mid to upper 20s.

SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/

Key message(s):

- Near normal temperatures return Tuesday and Wednesday.

- Low end chance for rain Wednesday and Thursday.

- Cold and windy behind a cold front on Thursday.

Tuesday and Tuesday Night: High pressure moves offshore with southwesterly winds at the surface. This should help temperatures return to seasonal values with forecast highs in the upper 50s to around 60 degrees. Skies should be mainly clear during the day followed by increasing cloudiness at night as the next storm system approaches. The clouds limit cooling with lows in the mid to upper 30s.

Wednesday and Wednesday Night: A potent upper trough takes shape to our west with southwest flow aloft. Southwest winds should also continue at the surface leading to another day of near normal daytime temperatures despite mostly cloudy skies. There is a low chance for some rain during the day, mainly in the coastal plain as low pressure tries to develop well offshore. Winds should increase later in the day as a cold front approaches with another low end chance for rain at night.

Thursday and Thursday Night: The aforementioned cold front crosses early in the day with breezy northwest winds expected. A reinforcing cold, dry air mass rushes in with the potential for gusty winds and increased fire danger. The setup looks similar to what was observed across the FA on Sunday so trends will need to be monitored. In addition, some locations could approach Cold Weather Advisory criteria at night should the winds diminish quickly enough.

LONG TERM /FRIDAY THROUGH SUNDAY/

Key message(s):

- Chilly and dry weather conditions favored.

There is high variance in the evolution of the upper pattern during the extended but dry conditions are favored across the Midlands and CSRA with below normal temperatures. The region will be in between upper troughs on Friday with another potent trough expected to move through the region Saturday night or Sunday. A front should accompany the passing trough but current guidance does not show a high chance for rain.

AVIATION /06Z MONDAY THROUGH FRIDAY/

High confidence in VFR conditions.

Cold high pressure will build over the area during this period with an anomalously dry air mass in place preventing any restriction concerns. Winds generally expected to be light and variable at 5 knots or less throughout the 24 hr forecast period. Skies expected to be mostly clear although some thin high cirrus may continue to traverse the southern Midlands and CSRA.

EXTENDED AVIATION OUTLOOK...A mid-week system moving through could bring brief restrictions although confidence is low due to limited moisture. Strong gusty winds expected on Thursday.

CAE WATCHES/WARNINGS/ADVISORIES

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