AFD_CHS

FXUS62 KCHS 260632 AFDCHS

Area Forecast Discussion National Weather Service Charleston SC 232 AM EDT Sun Apr 26 2026

.WHAT HAS CHANGED...

All sections updated.

.KEY MESSAGES...

- 1) A cold front will push into the area from the north later

today, bringing increased rain chances for the afternoon and evening.

- 2) Breezy and dry conditions Monday could support elevated

fire danger.

.DISCUSSION...

KEY MESSAGE 1: A cold front will push into the area from the north later today, bringing increased rain chances for the afternoon and evening.

Aloft, the tail end of a sharp shortwave trough extending across NC will brush the northern half of SC today and then move off the coast tonight. At the surface, a cold front will continue to draw closer and aligned across southeast SC through the morning, before the building high surges in from the north late today and through the evening. The forecast area already sits within a moist environment ahead of the front, with precipitable water values on the order of 1.3-1.5 inches. This will continue to support isolated to scattered shower activity through the late morning hours. As we get into the afternoon, moisture pooling ahead of the front and the presence of the developing sea breeze should yield a bit more instability than we saw on Saturday. Model soundings support MLCAPE in excess of 500 J/kg, especially along the coastal corridor. Hi-res model runs and the HREF generally paint the same picture with convection initiating either across the Pee Dee and Grand Strand regions or the Charleston Tri-County, and then gradually propagating down the coast ahead of the surging high. Overall, still not much support for severe weather though there is ~25 kts of mid-level flow with improved instability parameters. We still consider the severe threat to be quite low. Rainfall potential still looks quite spatially varied and dependent on the exact placement and movement of showers and thunderstorms. It is notable that the HREF has contours of 30+ percent of greater than an inch in 3-hours, mainly along the coast. So there is some potential for localized areas of 0.50-1.00" of rain, while the majority of locations still see considerably less than that. Then through the evening and into the overnight, much drier and cooler air will arrive as the high surges in from the north.

KEY MESSAGE 2: Breezy and dry conditions Monday could support elevated fire danger.

A drier airmass will settle into the region Monday as high pressure builds south from the Northeast, leading to falling dew points into the upper 40s to mid 50s, and possibly lower inland during peak heating. This will result in minimum RH values generally in the 35- 45% range. Northeast winds will be breezy in the morning with gusts around 20-25 mph, easing through the afternoon. While the current forecast features conditions shy of critical thresholds, fuels remain unusually dry. Considering the ongoing drought and dire forestry conditions, even marginal RH and wind conditions could still support enhanced fire behavior.

Although some rainfall is expected today, coverage is expected to be scattered, and not all areas will receive meaningful wetting rain. As a result, elevated fire weather conditions will be possible, especially where little or no rainfall occurs. A Fire Danger Statement could be needed for portions of the forecast area. We will continue to assess, especially after today's rainfall event.

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...

The 06z TAF period begins with VFR conditions at KCHS, KJZI, and KSAV with isolated showers around the area. These showers will continue for the next several hours, but should have no impact on the terminals even it they take a direct hit. Guidance suggests there could be a period of MVFR ceilings after sunrise that could last for a few hours through around midday. The main forecast challenge concerns shower and thunderstorm potential this afternoon. Showers and storms should first be near KCHS and KJZI, with development beginning around 17z or so. Showers and storms are expected to be concentrated along the coast so there is enough confidence to introduce TEMPO groups at KCHS between 18-20z and 18-21z at KJZI for thunderstorms. This activity should then shift down the coast to the KSAV area roughly for the 20-23z time period. While overall confidence is a bit lower, but still high enough to go with a TEMPO for thunder there as well. Once the shower and thunderstorm potential ends this evening, we should see northeast flow spread in with ceilings lower into the MVFR range for the very end of the TAF period.

Extended Aviation Outlook: Showers and possibly isolated thunderstorms associated could bring reduced vsbys/cigs midweek.

.MARINE...

Through tonight: The local waters will sit ahead of an approaching front for most of the day with wind speeds mostly around 10 knots but up to 10-15 knots at times. The big change will come late today and into the evening when high pressure builds in and a northeast surge pushes through. Northeast wind gusts into the 25-30 knot range will spread across the SC waters through the early morning hours and reach the GA waters soon thereafter. Small Craft Advisories will be issued for all waters outside Charleston Harbor, where wind gusts should mostly top out around 20-23 knots.

The pressure gradient across the local waters will relax Monday evening into Tuesday as high pressure settles and weakens. Small Craft Advisories will gradually drop off Monday night. Outside of a slight wind surge Wednesday with an approaching front, no additional marine concerns through the upcoming week.

.CHS WATCHES/WARNINGS/ADVISORIES...

GA...None. SC...None. MARINE...Small Craft Advisory from 11 PM this evening to 8 PM EDT

Monday for AMZ360. Small Craft Advisory from 11 PM this evening to 5 PM EDT Monday for AMZ362. Small Craft Advisory from 2 AM to 5 PM EDT Monday for AMZ364. Small Craft Advisory from 2 AM Monday to 5 AM EDT Tuesday for AMZ384.

BRS/BSH