textproduct: Charleston

WHAT HAS CHANGED

The Aviation Section was updated for the 06z TAFs.

KEY MESSAGES

- 1) An impactful system arrives during the later half of this weekend, resulting in renewed precipitation chances and perhaps a few thunderstorms.

DISCUSSION

KEY MESSAGE 1: An impactful system arrives during the later half of this weekend, resulting in renewed precipitation chances and perhaps a few thunderstorms.

Overnight into Sunday, guidance is depicting an upper level shortwave tracking across the extreme northeast CONUS, with a secondary shortwave moving towards the region from the west. At the surface, the secondary shortwave is accompanied by a surface low pressure moving across the deep south, with the region remaining in the developing warm sector of the aforementioned low. This will lead to wet conditions, given precipitable water values exceeding the 90th percentile of climatology near 1.25" in combination with upward vertical lift from the aforementioned shortwave producing scattered showers and perhaps even a few thunderstorms, starting Sunday morning and ending overnight into Monday. NBM 4.3 QPF probabilities seem to be running on the warm/hot side, whereas NBM 5.0 seems more in line with the 12Z ensembles. This would suggest probabilities for an inch are closer to the 20-30% range, with probabilities for half an inch generally in the 50-60% range. Aside from rainfall chances, temperatures will remain on the warmer side with overnight lows in the upper 40s to mid 50s and afternoon highs in the 60s and 70s. Southerly winds will be on the breezier side, sustained in the teens with gusts into the upper teens to lower 20s.

Confidence overall remains high in how the synoptic pattern is expected to unfold, namely in both the shortwave and surface low remaining fairly steady in strength as they move eastwards, though ensemble clustering analysis shows the feature producing the most uncertainty is the shortwave moving across the northeast. If that shortwave were to speed up faster than the majority of solutions would suggest, expect the surface low to strengthen quicker and thus become stronger, leading to increased rainfall amounts, whereas the opposite is also true. The NBM is likely holding onto the pops for too long into Monday and even early Tuesday to account for those slower solutions, so expect that to be refined with the updated data cycles.

AVIATION /06Z FRIDAY THROUGH TUESDAY/

VFR conditions will prevail at KCHS, KJZI, and KSAV through 06z Saturday.

Extended Aviation Outlook: The potential for flight restrictions will increase starting Sunday as an area of low pressure moves into the region.

MARINE

Dry high pressure will produce benign conditions across the local waters through Saturday. The setup will begin to change on Sunday as the local waters get situated between high pressure over the Atlantic and an area of low pressure approaching from the lower MS Valley. Southerly flow will increase through the day, with potential for Small Craft Advisory conditions for portions of the waters by late Sunday. The low should then shift offshore and track away to the northeast. As it does, there could be a northeast surge on the backside as high pressure builds in. This could bring another round of potential Small Craft Advisory conditions Monday into Tuesday.

CHS WATCHES/WARNINGS/ADVISORIES

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