textproduct: Columbia

WHAT HAS CHANGED

Airmass tomorrow is trending slightly drier, leading to lower dew points and heat index values. However, heat indices are still expected to be over 100F. Aviation discussion updated for 06z TAFs.

KEY MESSAGES

- 1. Hot conditions continue across the area, with limited chances for thunderstorms the next couple of days. Higher chances of rain return this weekend with a slow moving front.

DISCUSSION

Key Message 1: Hot conditions continue across the area, with limited chances for thunderstorms the next couple of days. Higher chances of rain return this weekend with a slow moving front.

Mid to upper level ridging over the Florida peninsula is expected to build northward today, partially in response to a trough over the lower Mississippi Valley. Dry mid-level air is also expected to remain in place, which is forecast to mix down to the surface in the afternoon. This will lead to lower dew points than previously forecast, and subsequently lower heat index values. However, heat indices are still expected to reach the 100-105F range across the area this afternoon, with a few locations slightly higher. In addition, this drier air will lead to just a low (up to ~10-15%) chance for an isolated thunderstorm, mainly in the eastern portions of the forecast area.

The aforementioned trough over the lower Mississippi Valley is expected to move eastward tomorrow and lift northward around the ridge over the area. As it does, the latest guidance stretches it out some. So, while the chances for thunderstorms are a bit higher tomorrow due to this, they do remain on the low side (up to ~20%). Lower rain chances continue on Friday as weak forcing continues. An approaching front for the weekend brings a greater chance for shower and thunderstorm activity to the region. Flow aloft is also forecast to become more zonal, which could lead to the front and associated precipitation chances lingering into next week.

As has been emphasized over the past week, the ongoing heat remains a concern. Temperatures are expected to remain 3-6 degrees above normal through Saturday, with height indices reaching the low to mid-100s. Most locations should remain below Heat Advisory criteria (108F), so no Heat Advisories are anticipated at this time. Continue to practice heat safety, especially with prolonged heat expected to persist. Please remain diligent if you have outdoor activities planned.

AVIATION /06Z WEDNESDAY THROUGH SUNDAY/

VFR conditions expected through the TAF period.

A drier air mass in place today should yield relatively quiet weather with only isolated convection expected this afternoon, too low to include in the forecast. Otherwise typical diurnal cumulus is expected to develop by 15z with surface heating and southwesterly winds 5 to 10 knots expected by 16z with some gusts to 15 to 18 knots during the afternoon due to deep mixing. Winds should diminish to around 5 knots by 09/02z. Low chances of morning fog/stratus.

EXTENDED AVIATION OUTLOOK...Daily rain chances and possible restrictions continue through at least midweek.

CAE WATCHES/WARNINGS/ADVISORIES

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