textproduct: Columbia

WHAT HAS CHANGED

Aviation discussion updated for 18z TAFs.

KEY MESSAGES

- 1. Moisture increases heading into the weekend and into next week, bringing rain chances back to the area.

- 2. More seasonably cooler and drier air returns by the middle of next week.

DISCUSSION

KEY MESSAGE 1: Moisture increases heading into the weekend and into next week, bringing rain chances back to the area.

An upper ridge remains over the Southeast this afternoon. Meanwhile, an upper low is developing off the Southeast coast. The ridge is forecast to retrograde westward, driven by the upper low moving westward over Florida and into the Gulf. This will leave our area on the periphery of the upper ridge. As it does, moisture is expected to slowly increase through the day Thursday before ramping up Friday into the weekend. Energy moving around the aforementioned upper ridge brings increased chances for showers and thunderstorms beginning Friday afternoon continuing through the weekend and into next week as moisture lingers. At the surface, a cold front will approach the forecast area, but stays just to the north working with the upper-level low to create showers and storms. Some localized storms may be severe mainly with localized wind gusts and heavy rainfall. PW's range between 1.6 and 2 with steep low- level lapse rates and downdraft CAPE as high as 1,000 J/kg aiding in localized downburst winds. Main window is in the afternoon and evening with a few isolated showers lingering after dark. Showers and storms return Saturday afternoon, but mostly sub- severe. A relative lull in activity remains possible for Sunday. As far as temperatures go, a gradual warming trend is forecast to continue today into tomorrow before returning to near normal as we head into next week.

KEY MESSAGE 2: More seasonably cooler and drier air returns by the middle of next week.

By mid-next week, an upper-level ridge in the 95th percentile will build over the Southern Plains. Northwesterly flow returns to the Mid-Atlantic and Carolinas. At the surface, high-pressure builds into New England promoting northeasterly flow. A cold frontal passage moves through by mid-week, but timing and intensity of the front is uncertain. It is likely high temperatures drop to the low to mid-80s with lows in the mid 60s, but uncertainty exists due to the large spread.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

VFR conditions generally expected through the valid TAF period.

SKC this afternoon with FEW high cirrus passing from time to time with no impacts at the terminals. High pressure is providing light and variable winds today, and that should continue overnight. Early Friday morning, some very brief fog is possible at AGS as per latest LAMP guidance, but confidence remains low. Winds Friday will continue to be light around sunrise, but may develop a more westerly component by late morning into the afternoon. FEW-SCT cumulus around 4-6kft MSL should also develop around midday Friday.

EXTENDED AVIATION OUTLOOK...Increasing chances for showers and storms Friday afternoon into the weekend. Morning VSBY restrictions are possible this weekend as well.

CAE WATCHES/WARNINGS/ADVISORIES

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