textproduct: Columbia

WHAT HAS CHANGED

Less convective coverage possible during the mid to late week. Aviation discussion updated for 00z TAFs and to add mention of possible patchy fog at some terminals.

KEY MESSAGES

- 1. Hot conditions continue across the area, with chances for thunderstorms the next couple of days.

DISCUSSION

Key Message 1: Hot conditions continue across the area, with chances for thunderstorms the next couple of days.

Active afternoon so far, especially near the Columbia metro and Lake Murray. Nearly 2500 J/kg of MLCAPE has developed in the moist airmass with surface dewpoints in the low to mid 70s. This led to robust initiation over Lake Murray before additional development has continued along the outflow from these initial storms with some back- building into Lexington County. PWAT's are near 2.0" at the moment and with storm motions being slowly toward the E/ENE, training storms could bring an isolated flash flood risk over the coming hours. With the influx of moisture this afternoon, DCAPE values are a bit less than yesterday but the main hazard in any strong to marginally severe storm will be damaging wind gusts from precip- loaded downbursts. Due to this, majority of the CWA is in a Marginal Risk for severe weather (level 1 out of 5) the remainder of the afternoon into this evening.

Heading into the remainder of the week, this repetitive pattern is expected to continue as the upper ridge breaks down due to the trough in the mid Mississippi Valley impinging on it. This will allow southwesterly flow to advect a couple weak shortwaves into the area along with maintaining PWAT's near 2", especially through Tuesday. Overall, this is expected to bring isolated to scattered convection each day this week where strong to marginally severe storms will be possible. This comes as mean HREF MUCAPE values exceed 2000 J/kg Tuesday with forecast soundings supporting this later into the week as well. It is worth noting that the latest blend has trended a bit drier Wednesday-Friday, likely in response to weak height rises, but at least isolated convection still seems possible on these days.

As has been discussed the last 4-5 days prolonged heat is expected to continue this week. Temperatures may end up a bit closer to normal Tuesday, but dewpoints in the low to mid 70s should bring heat indices as high as 105F. Ensemble guidance continues to show 850mb temperatures that remain near 20-22C the rest of the week and the potential for slightly less storm coverage Wednesday through Friday could bring max temperatures back to the upper 90s. These days could be when heat indices approach advisory criteria with dewpoints likely remaining toward the lower 70s so this potential will continue to be monitored. Regardless, If you must be out in the heat for prolonged periods of time, ensure that you hydrate properly and take frequent breaks to avoid heat related illnesses.

AVIATION /01Z TUESDAY THROUGH SATURDAY/

VFR conditions expected through the majority of the TAF period with brief restrictions once again possible in afternoon TSRA/SHRA.

Diurnally driven thunderstorms, enhanced from previous outflow boundaries, could impact mainly the SC terminals into late evening. TAFs for OGB, CAE, CUB and AIK all include a tempo group through about 03Z for gusty/erratic winds, and potential ceilings/visibility restrictions due to the pulse convection. These storms should generally be on a downward trend later this evening. However, given the rainfall at some terminals, high dew point values and light/variable winds, patchy fog could be a possibility toward daybreak and added a tempo group for IFR conditions at OGB and MVFR conditions at CAE/CUB.

Southwesterly winds will increase upwards of about 10kt by mid- morning Tuesday. Another round of diurnally driven convection is then expected to develop by midday Tuesday and continue through the afternoon. Have included a PROB30 group for thunderstorms at all terminals as a result.

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

CAE WATCHES/WARNINGS/ADVISORIES

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