AFD_CHS

FXUS62 KCHS 251901 AFDCHS

Area Forecast Discussion National Weather Service Charleston SC 301 PM EDT Sat Apr 25 2026

.WHAT HAS CHANGED...

All sections have been updated.

.KEY MESSAGES...

- 1) A cold front will push across southeast Georgia and the

South Carolina Lowcountry tonight into Sunday, bringing increased rain chances.

- 2) Dry conditions return early next week, with temperatures

building back to near normal. Chances for rain increase on Wednesday.

.DISCUSSION...

KEY MESSAGE 1: A cold front will push across southeast Georgia and the South Carolina Lowcountry tonight into Sunday, bringing increased rain chances.

The mid-levels will consist of shortwave energy moving overhead this evening, followed by another shortwave passing just to our north Sunday afternoon. At the surface, a cold front is approaching from the northwest, and will continue to move closer tonight. There is a decent plume of moisture ahead of this front, with PWATs increasing into the 1.25-1.5" range this evening overnight. The combination of the shortwave energy, lift from the front, and the increasing moisture will result in increasing shower and thunderstorm coverage. Both the CAMs and the synoptic models have convection forming along the sea breeze late this afternoon and moving inland, while additional convection associated with the front will form inland and shift towards the coast. We're only expecting isolated to scattered coverage late this afternoon, with scattered coverage this evening and overnight. Models and SPC Mesoscale Analysis point towards minimal instability. Therefore, the severe threat is very low. But there could be some rumbles of thunder. While locations directly impacted by passing showers and thunderstorms could see rainfall amounts of a 0.25" or more, overall rainfall will be quite variable.

By Sunday morning, the front will extend across the Carolina Midlands and into central Georgia, gradually pushing toward the coast through the day. The higher PWATs will be offshore. This will lead to scattered showers across our area during the afternoon, then decreasing into the evening. Dry conditions return Sunday night, when High pressure builds in from the north.

While any rainfall will be beneficial, this system is not expected to provide significant relief from the ongoing drought. Most areas should receive between 0.1-0.25". A few inland locations could see up to around 0.5", particularly where the front slows and convection becomes more concentrated. However, given the isolated to scattered nature of the convection, some areas could receive little to no measurable rainfall.

KEY MESSAGE 2: Dry conditions return early next week, with temperatures building back to near normal. Chances for rain increase on Wednesday.

As upper level ridging builds behinds the exiting disturbance, surface high pressure extends down the east coast Monday into Tuesday. This will bring the return of dry weather, with high temperatures starting in the mid 70s to lower 80s on Monday, rising a bit into the upper 70s to mid 80s on Tuesday. The surface pressure gradient will be increased as the surface high strengthens and brings breezy northeast winds on Monday. Lowest relative humidity values (~35-40%) are expected for inland areas, though we'll have to see how wetting the weekend rainfall ends up being before determining the fire danger threat for Monday. The pressure gradient relaxes on Tuesday as the surface high pressure weakens and dives southeastwards, leading to less breezy conditions as winds switch to become out of the southwest.

As the aforementioned cold front stalls off to our west on Tuesday, can't fully rule out some decaying showers/thunderstorms moving into our well inland counties during the late afternoon hours, but most look to remain dry. The main shortwave begins to move across the region during the early morning hours Wednesday, with the cold front following behind continuing rain chances throughout the day. While the deterministic models aren't showing renewed chances for rain on Thursday, ensemble (and clustering) solutions suggest rain chances continue Thursday. Clustering sensitivity analysis reveals the uncertainties revolve on the strength and positioning of the trough moving through, so expect that to be refined with additional model runs.

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...

18Z TAFs: Mainly VFR. There should be an increase in shower and thunderstorm activity late this afternoon as the sea breeze forms and moves inland, and a cold front approaches from the northwest. We maintained VCHS for the most likely time period. Amendments may be needed based on radar trends. The thunderstorms potential remains low. Shower activity should dissipate by the Sunday early morning hours.

Extended Aviation Outlook: Showers and isolated thunderstorms associated with a cold front could bring reduced vsbys/cigs Sunday and possibly again midweek.

.MARINE...

Tonight: A cold front will approach from the west. S winds in the evening will veer to the SSW after midnight, maintaining 10-15 kts. Seas will be 2-3 ft.

Sunday - Monday: The cold front continues to push through the region leading to increased chances for showers and thunderstorms throughout the day. Winds will be variable in strength and direction throughout the day as the cold front pushes offshore, with a surface high pressure building in from the north Sunday night bringing a switch to north-northeasterly winds along with dry conditions. A period of small craft level winds (sustained winds 20+ knots and/or gusts 25+ knots) are expected starting very early morning Monday expanding southwards, likely accompanied by 5-6 ft waves (~20nm+ out to sea), with conditions weakening throughout the afternoon as the pressure gradient begins to weakens.

Tuesday - Wednesday: The pressure gradient further relaxes on Tuesday as the surface high pressure weakens and dives southeastwards, leading to less breezy easterly winds which further swing to become out of the southwest overnight into Wednesday. Additional chances for showers and thunderstorms return Wednesday afternoon as an upper level disturbance moves through.

.CHS WATCHES/WARNINGS/ADVISORIES...

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

APT