textproduct: Columbia

WHAT HAS CHANGED

Updated discussion for a few changes due to TS Isaias. Primarily highlight the potential rainfall this upcoming weekend. Aviation discussion updated for 12z TAFs.

KEY MESSAGES

- 1. A wetter pattern develops into the weekend with some tropical connections.

DISCUSSION

Key Message 1: A wetter pattern develops into the weekend with some tropical connections.

Going into the latter part of the week and through the weekend, the biggest issue is going to revolve around the return of rainfall across the region. Rain chances are going to increase as we head into the weekend, mainly due to an increase in deeper moisture coming both from the Atlantic and Gulf. This will be fueled by the recently upgraded Tropical Storm Isaias, which will continue to develop and strengthen in the western Gulf. Guidance the past several days has been very consistent with this system continuing to strengthen and eventually track towards the central Gulf coast region later this week. The National Hurricane Center has this system generally following that pattern and track. On the current forecast track, east of the tropical system, deeper moisture will be pulled northward and inland across the eastern Gulf coast region late this week. Meanwhile, surface high pressure moving into the western Atlantic will be bringing additional moisture westward and inland across the southeastern U.S.

The deterministic and even some of the AI models, differ in the timing and track of the tropical system, but in regards to the moisture increase into the weekend across the forecast area, that appears to be of a much higher confidence. WPC leaned more towards a blend of the the AI guidance timing with the precip, which brings rainfall in earlier than some of the deterministic guidance runs. This would bring the potential for impactful heavy rainfall to the region this weekend, and due to this WPC has a Marginal Risk for ERO for much of the FA for Saturday, with Slight Risk areas both off to the west and east of our FA.

With all that being said, this event is still several days out, and the track of this tropical system is still being hashed out by NHC. Obviously any significant changes to either the intensity or the track of the eventual storm, could bring some changes to the rainfall forecast, heavy rainfall potential, and even the winds, so it is best to continue to monitor this system as it moves through the Gulf.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

VFR conditions through the TAF period.

For the time being, dry airmass will continue across the area, keeping vfr conditions at all taf locations. Some thin cirrus will be seen closer to the coastal plain today, but for our taf locations, few to scattered cirrus will be the dominant clouds Winds through the day will be more northeasterly around 5 kts, then becoming light to calm again tonight.

EXTENDED AVIATION OUTLOOK...VFR conditions will continue into late week with a dry air mass in place. As moisture increases by the weekend, restrictions are possible with increasing cloud cover and precipitation chances.

CAE WATCHES/WARNINGS/ADVISORIES

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