textproduct: Charleston

WHAT HAS CHANGED

The Aviation Section has been updated for the 12Z TAF issuance.

KEY MESSAGES

- 1) Scattered thunderstorms expected Sunday with an isolated severe threat possible.

- 2) A strong cold front will pass through southeast GA and southeast SC on Monday bringing the potential for severe thunderstorms, very gusty winds outside of storms, and brief periods of moderate to heavy rainfall.

- 3) Frost/freeze is possible Monday night and Tuesday night.

DISCUSSION

KEY MESSAGE 1: Scattered thunderstorms expected Sunday with an isolated severe threat possible.

Beginning Sunday morning, the surface pattern will feature high pressure wedged in across GA and the Carolinas with a sharpening coastal trough offshore. The trough is expected to lift northward and through southeast GA/SC as a warm front feature in the morning. As it does, a surge of low-level ThetaE air is anticipated which will bring an environment supportive of at least scattered coverage of thunderstorms. The near storm environment is interesting with the warm front in the vicinity, potentially MLCAPE values in excess of 1,000 J/kg, and ~30 kt of deep layer shear. Model soundings even show some decently veering profiles as well. All of this to say that there is potential for an isolated severe thunderstorm threat in the afternoon hours in the wake of the warm front. While the Sunday environment lacks the overall magnitude of the Monday environment (discussed in Key Message 2), it will bear watching as a sneaky severe threat.

KEY MESSAGE 2: A strong cold front will pass through southeast GA and southeast SC on Monday bringing the potential for severe thunderstorms, very gusty winds outside of storms, and brief periods of moderate to heavy rainfall.

A strong cold front is expected to move through southeast GA and southeast SC beginning late Monday morning and shifting off the coast by mid afternoon Monday. The front will bring a multitude of hazards to the region.

Severe Thunderstorms: A powerful mid-level trough and closed upper low is expected to shift east of the Mississippi on Monday, pushing a strong cold front through the forecast area. Monday should begin with some discreet convection well in advance of the cold front, followed by linear convection along the front. The ambient wind field looks to be quiet impressive and will provide plentiful shear across the 6 km (~50 kt) and 3 km (~40 kt) depths. The forecast area should be positioned well within the warm sector with temperatures warming into the mid to upper 70s and dew points rising into the upper 60s, yielding MLCAPE likely in excess of 1,000 J/kg. Model soundings suggest that winds will mostly be unidirectional despite the overall magnitude of shear, but a tornado threat will still be present both within any initial discreet convection as well as with the main line. Timing is still being refined, but the front should enter interior southeast GA by late morning/midday, then push off the coast by the mid afternoon. Damaging wind gusts are certainly the primary threat, followed by an isolated tornado, and with any hail threat certainly being a distant third.

Gusty Winds: As the strengthening wind field spreads across the area ahead of the front beginning Monday morning, mixing profiles will deepen and yield an environment capable of strong non-thunderstorm wind gusts through the morning and into the afternoon. A corridor of wind gusts of 35+ mph is possible across the area. A Lake Wind Advisory will almost certainly be needed, and there is even the possibility of needing a Wind Advisory for at least portions of the area.

Rainfall: Precipitable water values are forecast to rise into the 1.2-1.4" range ahead of the approaching front which would be in excess of the 90th percentile according to the CHS SPC Sounding Climatology for 3/16. Rainfall rates within convection will certainly be intense, but the good news is that storms should be moving quickly which should reduce the overall threat of excessive rainfall. The forecast is for general amounts of 0.5-1.0", with probabilistic data supporting a 30-40% chance of amounts in excess of an inch. So, as of now the risk of intense rainfall producing flooding isn't particularly notable.

KEY MESSAGE 3: Frost/freeze is possible Monday night and Tuesday night.

Cold high pressure will build over the area Monday night through the middle of next week. An advection freeze is possible Monday night, mainly over inland portions of southeast GA and SC where temps could dip into the lower 30s for a couple hours Monday night into Tuesday morning. By Tuesday night, cold high pressure will settle over the area, allowing winds to diminish after sunset. This will set the stage for a fairly widespread frost and/or freeze, as temps will drop into the upper 20s inland to low/mid 30s closer to the coast. Frost/Freeze headlines are likely to be needed for both of these nights.

AVIATION /13Z SATURDAY THROUGH WEDNESDAY/

Patchy dense fog could linger at the CHS/JZI/SAV terminals through about 14Z this morning, producing vsbys to around 1/2 SM and IFR/LIFR cigs temporarily as fog lifts. Thereafter fog is anticipated to mix out/dissipate quickly with all terminals experiencing prevailing VFR conditions through 12Z Sunday, although shower activity associated with a coastal trough could begin impacting the terminals late in the TAF period. Future TAF issuances could need to include flight restrictions starting around 12Z Sunday.

Extended Aviation Outlook: Brief flight restrictions are possible at in showers and thunderstorms Sunday through Monday evening at the CHS, JZI, and SAV terminals. Gusty winds are also expected on Monday at all terminals.

MARINE

Strong southerly winds will develop Sunday night into Monday ahead of a powerful cold front. Solid Small Craft Advisory conditions expected, with the possibility of Gales over the Charleston nearshore waters due to 35 kt gusts. Small Craft Advisory conditions expected to linger into Tuesday afternoon before subsiding.

EQUIPMENT

The KCLX radar is scheduled for radome panel replacement March 17-20, 2026. The radar will be down during this time. Users are encouraged to use data from the following nearby radar sites during the maintenance outage:

KCAE - Columbia, SC KLTX - Wilmington, NC KJAX - Jacksonville, FL KVAX - Moody AFB, GA KJGX - Robbins AFB, GA

CHS WATCHES/WARNINGS/ADVISORIES

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