textproduct: Columbia

WHAT HAS CHANGED

No significant changes to the forecast. Updated aviation discussion for the 18z TAFs.

KEY MESSAGES

- 1. Fire weather concerns remain elevated this week.

- 2. Increasing rain chances this weekend into early next week.

DISCUSSION

Key Message 1: Fire weather concerns remain elevated this week.

Elevated fire weather concerns continue this week as a dry air mass remains over the region with much of the area in severe to extreme drought. Temperatures will continue to rise to well above average through the end of the week into the weekend. While winds will generally be light due to high pressure ridging into the area, there remains a high probability of relative humidity dropping below 30 percent, potentially as low as 20 percent each afternoon through Friday. Winds could be a bit stronger today and Friday but likely remain below Fire Danger Statement criteria with gusts into the teens. The SC Forestry Commission continues a Burn Ban for South Carolina until further notice.

Key Message 2: Increasing rain chances this weekend into early next week.

The highly amplified 500mb pattern over the CONUS will begin to breakdown this weekend as a more progressive pattern takes place beginning with a cold front moving through this weekend. Ensemble mean PWATs generally rising to 125 to 150 percent of normal will favor increasing chances for rain associated with this front. Blended guidance also indicates moderate confidence in sbCAPE greater than 500 J/kg with thunderstorms possible Saturday as a result. With this progressive pattern in place, additional shortwaves will be possible into early next week leading to additional chances for rain and slight chance for thunderstorms. We will still likely have a ways to go to break the drought with only around 10 percent of GEFS members showing greater than an inch of rain through Tuesday (and we will need more than that). The longer term pattern favor a more active (wetter) pattern through the end of the month and into early May with teleconections such as the NAO, favoring general troughing over the eastern CONUS.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

The primary aviation concern through the TAF period will be reduced visibility due to smoke from ongoing wildfires across southern and central GA. Smoke is being advected northeastward into the region, with the greatest impacts expected at terminals along and south of the I-20 corridor, including KAGS and KCAE.

Visibility reductions to 3-5 SM have already been observed at times today, and smoke is expected to persist across the area through tonight and into Thursday. Hires guidance from the HRRR smoke model suggests another surge of dense near-surface smoke may move into the region from the wildfires between roughly 07Z and 11Z. Confidence in the magnitude of any additional visibility reductions remains uncertain, but periodic restrictions below VFR are possible.

Given the variability in smoke concentrations, visibility forecasts may require frequent updates to reflect short-term trends over the next 1-2 days.

EXTENDED AVIATION OUTLOOK...Periods of visibility restrictions due to smoke are likely to persist through at least Friday as southwest flow continues to transport smoke into the region. Otherwise, dry conditions should limit fog development. Rain chances increase this weekend, which may introduce restrictions at times, though confidence in timing and coverage remain low.

CAE WATCHES/WARNINGS/ADVISORIES

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