textproduct: Columbia

WHAT HAS CHANGED

Aviation discussion updated for 12z TAF.

KEY MESSAGES

- 1) Breezy and warm conditions expected through the end of the week, with temps well above normal.

- 2) Rain is still expected this weekend but the amounts are generally uncertain at this point. The heaviest rain should fall Saturday night or Sunday.

DISCUSSION

KEY MESSAGE #1: Breezy and warm conditions expected through the end of the week, with temps well above normal.

An active and amplified pattern is forecast to develop and overspread the entire CONUS through the end of the week. Multiple strong low pressure systems are forecast to develop to our northwest and push eastward north of a strong Bermuda high that is influencing our weather. While there is still a lot of spread within LREF guidance regarding the overall synoptic pattern, ensembles continue to indicate an anomalously warm stretch is expected through Friday. 850 hPa temps will be into the 90th-99th percentile both Thursday and Friday which should yield temps in the upper 70s or low 80s each day. Additionally, breezy southwesterly winds are expected each day, with the strongest winds likely today. A Lake Wind Advisory has been issued today from 10a through 7p for wind gusts of 25-30 mph expected.

KEY MESSAGE #2: Rain is still expected this weekend but the amounts are generally uncertain at this point. The heaviest rain should fall Saturday night or Sunday.

As mentioned above, the overall pattern will favor multiple waves of low pressure traversing the eastern US through this weekend. With persistent southwesterly flow aloft, a warm and moisture rich atmosphere (for this time of year at least) is expected to reside across much of the southeastern US. As such, rain chances are expected Friday through Sunday. The first increase in precip chances will arrive on Friday, though generally think the NBM is too aggressive with overall PoPs. Even if it isn't, overall rainfall totals should be fairly low across the area on Friday. The best forcing should be well to our north at this point & the surface front should gradually begin stretching out. Deterministic guidance is in a bit better agreement than it was 24h ago on the specifics for rain chances this weekend but the ensemble guidance continues to reveal a lot of spread and potential outcomes for the system this weekend. There are a couple of camps that LREF guidance seems to fall into right now: 1) is a deeper trough and shortwave digging through the OH valley on Saturday and into Sunday, or 2) a less amplified wave that passes to our north. The differences between these two would have pretty stark impacts on our sensible weather this weekend, with scenario 1 yielding a surface low developing near the forecast area and deepening as it pushing out to sea. Widespread rain would be expected on Saturday night and Sunday associated with this. Scenario 2 would have lesser rain overall. Looking at the whole of guidance, it seems that a sort of blend between these two is likely, which would still result in rainfall across the area but really not enough to continue denting the drought. However, much of this is up in the air as the overall pattern is very complex and uncertainty is quite high on the details of the forecast this weekend.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

Patchy morning fog/stratus lingers for the next hour or two before VFR conditions are expected outside of possible periods of MVFR ceilings near AGS/DNL later this morning.

Light southerly to southwesterly winds remain with the 25-30 kt LLJ in place across the region. Periods of stratus and fog have moved through AGS/OGB over the last couple hours and associated restrictions may continue for a few more hours before these generally clear. A BKN to OVC deck around 5000 ft has begun moving into the region and is expected to remain in place much of the day with some SCT clouds between 2500 to 3500 ft possible, especially near the Augusta terminals where brief MVFR ceilings could be possible around 14z until 18z. 10-15 kt southwesterly winds are expected to be gusty with gusts up to 25 kts possible across the area after 16z. These winds should relax this evening and overnight with light southwesterly winds likely as scattered mid level clouds remain with a BKN to OVC cirrus deck. As moisture ramps overnight, ceilings around 4000 to 5000 ft could develop again where more morning fog cannot be ruled out mainly near OGB and AGS again.

EXTENDED AVIATION OUTLOOK...High low level moisture will bring chances for morning fog/stratus through the remainder of the week and into the weekend. While a couple stray showers cannot be ruled out Thursday, the main rain chance continues to trend toward Friday and Saturday.

CAE WATCHES/WARNINGS/ADVISORIES

SC...Lake Wind Advisory from 10 AM this morning to 7 PM EST this evening for SCZ016-018-020>022-025>031-035-037-038-041- 115-116-135>137. GA...Lake Wind Advisory from 10 AM this morning to 7 PM EST this evening for GAZ040-063>065-077.