textproduct: Columbia

WHAT HAS CHANGED

Strong to severe thunderstorms possible again on today bringing the risk of damaging wind gusts, small hail, and localized flash flooding. Aviation discussion updated for 12z TAF issuance.

KEY MESSAGES

- 1. Strong to severe thunderstorms possible again on Sunday.

DISCUSSION

KEY MESSAGE 1. Strong to severe thunderstorms possible again on Sunday.

Another round of showers and thunderstorms are expected to develop on Sunday, bringing impacts to much of the FA. A weak surface boundary is anticipated to slowly move into the region, serving as a lifting mechanism for afternoon and evening convection. This will be aided further by the passage of an upper level trough and associated shortwave. The latest SPC outlook places much of our CWA in a Slight (2/5) risk for severe weather, with damaging wind gusts as the primary threat and large hail as the secondary risk. Modeled soundings show ample CAPE in excess of 2000 J/kg and an inverted-V signature indicative of the downburst wind threat. The primary failure mode will be whether skies are able to clear out and allow the atmosphere to destabilize sufficiently. PWATs are expected to be higher on Sunday which would also increase the risk of heavy rainfall and localized flash flooding. This potential is highlighted in the latest WPC ERO which puts the southern half of the CWA in a Slight (2/4) risk for excessive rainfall, with a Marginal elsewhere. Temperatures are not expected to be as high as yesterday with forecast highs in the upper 80s in the Pee Dee and in the lower to mid 90s elsewhere.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

Another round of diurnal convection late afternoon/evening expected then restrictions associated with stratus and fog late tonight.

Light and variable to calm wind through sunrise then winds gradually pick up from the east to around 5-6 knots after 15z. An upper level trough and upper disturbance approaching the region combined with diurnal instability and a southward sinking cold front will provide increased chances of late afternoon and evening convection across the region. Similar to today, some storms expected to be severe with damaging wind gusts. Will carry a PROB30 group for now given some uncertainty in exact timing and location that can be pinned down more with time. As the front sinks southward through the night, low clouds and fog are expected behind the front.

EXTENDED AVIATION OUTLOOK...Diurnal storm chances continue into the first half of the week.

CAE WATCHES/WARNINGS/ADVISORIES

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