textproduct: Columbia

SYNOPSIS

A cold front moving into the Southeast this morning ushering in an arctic air mass which will remain in place into early next week. A Cold Weather Advisory has been issued for the whole area as a result. Weak ridging should then allow for air mass recovery by the middle of next week.

NEAR TERM /THROUGH TONIGHT/

Key message(s):

- Dangerously cold weather likely tonight and Monday morning - A few light showers this morning, gusty winds this afternoon

Early this morning: A cold front is working into the upstate of SC early this morning as scattered showers begin pushing east through the remainder of the morning. Winds already are beginning to gust toward 15-20 mph and will steadily increase.

A strong cold front will move east of the forecast area later this morning. Temperatures will drop throughout the day, so it's worth noting that the forecast daytime high temperatures of mid to upper 50s have already been reached. Winds will gust to around 30 mph following the frontal passage and continue through the afternoon. As strong cold advection sets in during the evening, strong winds will continue to mix down over the relatively warm lakes despite gusts diminishing over land. Gusts up to 35 mph are possible. For this reason we have continued the Lake Wind Advisory from 4 PM today to 4 AM Monday.

The strongest cold advection arrives this evening as an arctic air mass settles into the Southeast. Abnormally cold temperatures and continued sustained winds near 10 mph will lead to dangerously cold wind chills in the teens or even single digits. Historically for our area this can lead to issues with freezing pipes if precautions are not taken such as dripping faucets, covering outdoor faucets, or opening cabinets to let warm air circulate to plumbing on exterior walls. These dangerously cold wind chills will impact the early morning commute, including children at bus stops and outdoor workers. An area wide Cold Weather Advisory remains in effect from 8 PM this evening to 10 AM Monday.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/

Key message(s):

- Temperatures well below average Monday into Monday night, moderating Tuesday.

Northwest flow aloft and a very dry air mass ridging into the area with HREF mean PWATs less than 0.4 inch. A very cold start to the day expected with highs struggling to warm through the day. EC EFI indicates below -0.9 for high temperatures Monday indicating very anomalous cold continuing through the day as the surface high pressure slowly shifts over the area. High probability (60-80%) that temperatures remain below 40F through the day. Winds becoming light, however, so wind chills will likely not be a factor through Monday night. With this very dry air mass, clear skies and mostly light winds will support a strong radiation night, although models have generally trended a bit stronger with the low level jet overnight which would prevent ideal radiational cooling conditions. Fairly high confidence with limited spread in blended guidance distribution in lows in the low to mid 20s tonight, with sheltered locations likely dipping into the teens once again.

Temperatures rising Tuesday with more of a zonal flow developing aloft and surface high pressure shifting offshore. As the air mass still continues to moderate, do expect temperatures to remain below average, but highs likely in the low to mid 50s with lows in the low to mid 30s, significantly warmer than the previous couple days.

LONG TERM /WEDNESDAY THROUGH SATURDAY/

Key message(s):

- Above average temperatures with chance of rain late week.

Benign weather overall expected through the long term period as weak ridging develops over the area. NAEFS mean and EC EFI tables indicate near average conditions which indicates a fairly typical weather pattern expected. Overall, expect above average temperatures through the end of the week and into the weekend. Moisture increase expected Thursday into Friday with a shortwave approaching the area leading to chances for rain, although system appears relatively weak and progressive, limiting rainfall amounts. Timing has not been very consistent run to run among global models, although the general trend has been sharper with a shortwave approaching from the west and a faster arrival of rain chances, mainly favoring Thursday night.

AVIATION /13Z SUNDAY THROUGH THURSDAY/

MVFR cigs and a few showers possible ahead of a cold front. Behind the front, expect gusty NW winds through the afternoon.

Scattered showers continue to push through the terminals this morning with MVFR ceilings seen at all of the TAF sites except OGB, but these should gradually build in here as well. Winds remain southwesterly to westerly around 10 kts this morning. Ceilings should gradually clear through around 15z and return to VFR for this afternoon and the remainder of the TAF period. Winds will sharply shift to the northwest with the frontal passage with gusts to 20-25 knots expected through the afternoon. Gusts then diminish around sunset as winds turn to the N.

EXTENDED AVIATION OUTLOOK...Widespread restrictions unlikely in the extended as a cold, dry air mass settles into the region.

CAE WATCHES/WARNINGS/ADVISORIES

SC...Lake Wind Advisory from 4 PM this afternoon to 4 AM EST Monday for SCZ016-018-020>022-025>031-035-037-038-041-115-116- 135>137. Cold Weather Advisory from 8 PM this evening to 10 AM EST Monday for SCZ016-018-020>022-025>031-035-037-038-041-115- 116-135>137. GA...Lake Wind Advisory from 4 PM this afternoon to 4 AM EST Monday for GAZ040-063>065-077. Cold Weather Advisory from 8 PM this evening to 10 AM EST Monday for GAZ040-063>065-077.