textproduct: Columbia

WHAT HAS CHANGED

A Severe Thunderstorm Watch has been hoisted until 1a for the northern half of the forecast area. Aviation discussion updated for 00z TAF.

KEY MESSAGES

- 1. Severe thunderstorms and damaging winds are possible late this afternoon into the evening hours. Drier conditions then move in for the late week before rain chances increase again this weekend.

DISCUSSION

- 1. Severe thunderstorms and damaging winds are possible late this afternoon into the evening hours. Drier conditions then move in for the late week before rain chances increase again this weekend.

In collaboration with SPC, we have issued a Severe Thunderstorm Watch, valid until 1a, for the northern half of the area. An impressive cluster of convection is diving out of western NC into the upstate and is progged to approach the area over the next several hours. Maintaining this is anomalously strong wind shear, with 6km shear values >40 knots & SBCAPE 2000-3000 across the area. Expecting this convection to continue consolidating as it progresses southward, likely yielding damaging winds. DCAPE values are 1200-1400 across our area (higher values in the upstate!) which will help to maintain potentially damaging wind gusts. Shear is so anomalously strong that it wouldn't be surprising if there was an embedded tor within the convection, though that threat looks maximized to our north. The convection will likely clear the area between 04z and 07z.

Remainder of forecast period: Solid agreement remains in ensemble and model guidance that behind the front, much drier air works in Wednesday through Friday with PWAT's falling to nearly 2-3 standard deviations below normal. This should bring relief from the humidity and nice weather as temperatures remain near normal. Heading into the weekend, global models indicate another sharp shortwave rounding the robust ridge (which should have retrograded near the Four Corners region at this point). Increased southwesterly flow should bring returning moisture and increased rain chances as this wave works into the region.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

VFR conditions expected outside of line of convection moving into the region this evening.

A line of convection just ahead of an approaching cold front continues to sink southward through western NC and should impact at least the Columbia metro area later this evening. Included a tempo group from 02z-05z for gusty winds in TSRA with IFR vsby restrictions. Lower confidence in storms reaching the other terminals so decided to continue the PROB30 there. Otherwise, southwesterly winds diminishing overnight and shifting to the northwest after dawn as the front pushes through the region. Expect convective debris clouds to limit fog/stratus concerns and hi-res guidance keeps VFR conditions through the period. Northwesterly winds pick up to around 5 to 8 knots after 15z. EXTENDED AVIATION OUTLOOK...Drier air moves in for the second half of the week. Next chance for rain and restrictions not expected until the weekend.

CAE WATCHES/WARNINGS/ADVISORIES

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