textproduct: Columbia

WHAT HAS CHANGED

Added a Slight Chance of thunderstorms Monday afternoon. Otherwise, the forecast for Monday remains largely unchanged with highs around 100 degrees. Aviation discussion updated for 12z update.

KEY MESSAGES

- 1. Dangerous heat continues into this week with highest temperatures expected today.

- 2. Storm coverage more limited today, then increasing chances the remainder of the week.

DISCUSSION

KEY MESSAGE 1: Dangerous heat continues into this week with highest temperatures expected today.

Upper ridging is expected to persist into early next week with continued above average temperatures expected. Today should be the hottest day of this stretch with forecast highs around 100 degrees. With a layer of relatively hot and dry air moving in aloft, lower dew points are expected which should result in similar heat index values to yesterday despite the higher temperatures. Unfortunately, Tuesday may be another hot and humid day meaning another extension of the ongoing Heat Advisory is possible. Modest improvement in the heat and humidity is possible during the mid to late week period as the ridge breaks down, though this is no guarantee and significant heat relief is not expected during the next seven days.

KEY MESSAGE 2: Storm coverage more limited today, then increasing chances the remainder of the week.

With the aforementioned layer of hot and dry air expected overhead today, convection should struggle to develop this afternoon and evening. Having said that, some of the CAMs show spotty shower and thunderstorm activity during the afternoon hours. With this in mind, added a Slight Chance for thunderstorms across the forecast area. Looking ahead, convective activity should favor the eastern half of the FA Tuesday and Wednesday. The ridge will begin to break down for the second half of the week which will lead to increased chances for shortwaves to move into the area with blended guidance favoring higher chances for precipitation Friday and into the weekend.

AVIATION /12Z MONDAY THROUGH FRIDAY/

VFR conditions expected through the TAF period, outside of a low chance for thunderstorm activity today.

Some MIFG possibly early Monday, but restrictions not expected. Otherwise, typical summer conditions expected through the TAF period today with westerly winds 5-10 knots, cu field around 5k feet, and an outside chance for thunderstorms this afternoon. Included a prob30 group at this time, from 19z to 00z, but relatively dry air should keep storms quite isolated today.

EXTENDED AVIATION OUTLOOK...Diurnal chances for thunderstorms continue Tuesday through the end of the week.

CAE WATCHES/WARNINGS/ADVISORIES

SC...Heat Advisory until 8 PM EDT this evening for SCZ016-018- 020>022-025>031-035-037-038-041-115-116-135>137. GA...Heat Advisory until 8 PM EDT this evening for GAZ040-063>065- 077.