textproduct: Columbia

SYNOPSIS

Mostly dry conditions are expected today with lingering low clouds. Another round of rain moves in tonight through Monday. Dry conditions are then anticipated for the mid-week period while temperatures remain below normal. The next chance of rain arrives Thursday night into Friday.

NEAR TERM /THROUGH TONIGHT/

Key message(s):

- Cold with low clouds once again today.

- Fog developing tonight, although more patchy than last night.

Widespread low clouds over the area once again today, although PWATs remain much lower compared to yesterday generally around half an inch. HiRes forecast soundings indicate a strong subsidence inversion in place today which will lead to trapped near surface moisture. With weak low level flow and high cirrus streaming over the area limiting sun, it will be hard to break the pattern we've been stuck in the last few days. As a result, generally expect low clouds with temperatures in the 40s for much of the day. Rain is less likely today, however, as radar right now indicates strongest isentropic lift associated with a boundary near the FL/GA line. An isolated shower remains possible in the southeasternmost portion of the area but most of the area expected to remain dry.

Tonight, unlike last night, model consensus shows limited clearing in clouds. While stratus expected to be widespread, fog likely more patchy, favoring the northern portion of the forecast area which has a better chance of some clearing. Not out of the question that dense fog develops but it is not expected to be as widespread as last night into this morning. The lingering clouds will likely limit radiational cooling with lows generally in the upper 30s to around 40. A shortwave will approach the area tonight, leading to a bit of an increase in deeper moisture. Rain chances will increase late tonight into Monday morning, although highest chance will be after daybreak.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/

Key message(s):

- Chance of rain on Monday, mainly in the morning.

- Drier and Continued Cool on Tuesday.

Monday and Monday Night: A weak upper level trough axis will approach from the west in the morning, then shift across the area in the afternoon. A northwest flow will then develop aloft at night on the back side of the trough axis.

Rain will spread into the area during the early-mid morning hours, with probabilities in the high chance to likely range. Precipitable water values do not appear to rise much above 0.75 to 1.00 inches, so intensity and overall rainfall amounts should remain light. While there could be a lingering rain chance into late afternoon with the passage of the trough axis, the bulk of the precipition should come to an end around midday or by early afternoon. Temperature profiles appear to support all rain for this event, but the probabilities are non-zero for a few flakes up toward the Catawaba region. Temperatures will be held down significantly by the precipitation, cloud cover and northerly flow. Have adjusted forecast highs from the blended guidance down a couple of degrees, with most areas only expected to warm into the lower to mid 40s across the Midlands and upper 40s to lower 50s across the CSRA.

Skies will begin to clear as drier air moves in during the nighttime hours. Cold air advection will contribute to cool overnight temperatures, with lows in the 20s most areas.

Tuesday and Tuesday Night: A nearly zonal flow will prevail aloft, while surface high pressure settles over the region during the day then shifts to the east at night. There should be a considerable amount of sunshine during the day, but the continued strong cold air advection will result in another unseasonably cool day with highs 10- 15 degrees below normal. A southwest flow will develop due to return flow around the surface high at night, resulting in moderating temperatures with lows in the lower to mid 30s.

LONG TERM /WEDNESDAY THROUGH SATURDAY/

Key message(s):

- Dry and warmer Wednesday and Thursday.

- A strong cold front will move through on Friday.

An upper level trough will prevail over the eastern half of the country during the mid-week period, with a southwest flow in place at the surface. Moisture will be very limited, so dry conditions are expected. Temperatures will moderate to near normal during this period. Ensembles support another deep upper trough and associated strong cold front at the surface moving through Friday and Friday night. This will result in the next chance of rain across the area. Behind this cold front, a dry and considerably cooler airmass will settle in.

AVIATION /18Z SUNDAY THROUGH FRIDAY/

Low clouds continue today with IFR/low MVFR ceilings. Widespread IFR developing tonight.

Low level moisture remains in place with IFR/MVFR ceilings already in place. Model trends continue to indicate that restrictions will remain in place into tonight with widespread IFR ceilings and potentially LIFR developing later tonight. Fog not expected to be as dense tonight with clouds not expected to clear. Still potential for visibility restrictions tonight. A shortwave late tonight into Monday morning will lead to potential for showers and brief IFR visibilities as well. Overall model consensus shows lingering restrictions into Monday.

EXTENDED AVIATION OUTLOOK...Lingering restrictions Monday with drier air expected Tuesday through the end of the period.

CAE WATCHES/WARNINGS/ADVISORIES

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