textproduct: Columbia

WHAT HAS CHANGED

Aviation discussion updated for 00z TAF issuance.

KEY MESSAGES

- 1. Daily chances for showers and storms continue into the first part of the week, with locally heavy rain possible.

- 2. Relatively cool temps expected Sunday followed by a warming trend.

DISCUSSION

Key Message 1: Daily chances for showers and storms continue into the first part of the week, with locally heavy rain possible.

A cold front continues to sag southward into the forecast area this evening bringing isolated showers and a few thunderstorms. Convective trends have diminished during the last hour and activity should continue to wane. Any areas of localized flooding should recede as well. Rain chances will end once the front pushes through but it remains unclear how far south the boundary will progress. The best chance of rain tonight will be across the CSRA. The front is forecast to meander around the region as we head into the work week. Multiple pulses of shortwave energy are forecast to move across the area, keeping the daily chances for rainfall going into the first part of the week. Guidance then suggests an offshore low could develop and move away from shore, essentially drying the area out for the last half of the week.

Key Message 2: Relatively cool temps expected Sunday followed by a warming trend.

The aforementioned cold front is forecast to usher in some cooler and drier air for Sunday across the forecast area. We currently have mid to upper 70s forecast for highs tomorrow, but some of the latest guidance has been coming in cooler as cloud cover associated with the front should aid in keeping temperatures on the cooler side. Decided not to adjust temps at this time, but the may need to be lowered in future forecast packages. After tomorrow, an upper ridge begins building over the area for much of the week, leading to a gradual warming trend through the rest of the period.

AVIATION /00Z SUNDAY THROUGH THURSDAY/

Isolated to scattered showers and storms continue across the area this evening. Ceiling restrictions possible tonight into Sunday.

The cold front is nearing the Pee Dee region from the north and should continue to work through the FA overnight tonight. A look at radar shows isolated to scattered showers/storms persisting across the area but not impacting any of the terminals at the moment. As coverage continues to decrease over the coming hours, cannot rule out some of this activity reaching the terminals, but confidence remains low thus have maintained a PROB30 group for this. With multiple outflow boundaries across the area, winds have been fairly variable, but should become increasingly northerly to northeasterly as the front works through. As the front passes tonight, winds likely pick up toward 7-11kts, continuing into Sunday morning. There remains uncertainty in how far south the front will push, thus where greater low level moisture is and the greatest risk for stratus development. Majority of guidance is more confident in AGS/DNL/AIK remaining near or south of the front, but the Columbia terminals may end up just north of it. Overall, periods of MVFR to possibly IFR ceilings are expected after 08-10z, especially south of the front. LAMP and HRRR guidance is fairly aggressive in keeping MVFR ceilings much of the TAF period, especially near AGS/DNL/AIK, while having slightly better mixing north of here, bringing VFR conditions by the late morning to early afternoon. The 12z HREF is not as pessimistic and favors a return to VFR ceilings for all terminals by the early afternoon. Current thinking is MVFR ceilings could stick around a bit longer south of the front with the greater moisture in place, but will continue to evaluate this as new guidance comes in.

Winds through the day are expected to remain out of the northeast to east around 5-8 kts. Isolated to scattered showers and storms may become possible during the afternoon, mainly near the CSRA but confidence remains too low to add in the TAF at the moment.

EXTENDED AVIATION OUTLOOK...Unsettled weather should continue into early next week until drier air moves into the region mid- week.

CAE WATCHES/WARNINGS/ADVISORIES

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