AFD_CHS

FXUS62 KCHS 270650 AFDCHS

Area Forecast Discussion National Weather Service Charleston SC 250 AM EDT Mon Apr 27 2026

.WHAT HAS CHANGED...

All sections have been updated.

.KEY MESSAGES...

- 1) Breezy and dry conditions across the forecast area today.

- 2) Minor coastal flooding is possible with the evening high

tide cycle along the southeast South Carolina coast.

- 3) Rain chances will increase from midweek through the

weekend, though no significant impacts are expected at this time.

.DISCUSSION...

KEY MESSAGE 1: Breezy and dry conditions across the forecast area today.

High pressure will continue to build into the area early this morning resulting in breezy northeast flow even in the pre-dawn hours. As the day progresses, the gradient will relax and the northeast flow will gradually diminish. Accompanying the northeast surge is a solid blanket of low stratus that will result in cloudy conditions through the morning. However, by midday the stratus should start to scatter out and yield plenty of sun for the afternoon. Temperatures will be below normal for the day, with low to mid 70s across southeast SC and mid to upper 70s for southeast GA. The forecast is dry, but relative humidity values aren't expected to be too low. We should see RH values away from the coast dip into the 30-40 percent range, lowest across far interior southeast GA.

KEY MESSAGE 2: Minor coastal flooding is possible with the evening high tide cycle along the southeast South Carolina coast.

Astronomical tide levels are beginning to rise as we move closer to the upcoming (5/1) full moon. Strong northeast flow along the coast and across the adjacent coastal waters is already driving tide levels higher as well, with the current tide departure around 1.4 feet. For the evening high tide cycle, the astronomical tide is 5.59 ft MLLW meaning that we would need a departure of 1.41 ft to reach the minor coastal flood threshold of 7 ft MLLW. We will continue to monitor tide trends through the day and it is possible a Coastal Flood Advisory could be needed for Charleston and Coastal Colleton counties.

KEY MESSAGE 3: Rain chances will increase from midweek through the weekend, though no significant impacts are expected at this time.

A surface low tracking across the Tennessee and Ohio Valleys could bring periods of scattered showers and isolated thunderstorms Wednesday into Thursday. Instability remains limited, so any thunderstorms that develop are expected to be weak and non-severe, with low potential for significant impacts.

A second system could affect the region early this weekend, bringing another round of rain chances. Similarly, the risk of hazardous weather remains low at this time.

.AVIATION /06Z MONDAY THROUGH FRIDAY/...

The 06z TAF period begins with low MVFR ceilings in place at KCHS, KJZI and KSAV. These ceilings will stick around for an extended period of time as satellite imagery shows a deep reservoir that extends upstream across much of NC and into the VA Tidewater region. Model guidance favors these MVFR ceilings scattering out and conditions returning to VFR somewhere in the 16-18z time period. Northeast winds will remain elevated as well through much of the period, with more persistent gusts up to 20 knots at KJZI. Winds will diminish a bit by the afternoon and then turn more easterly with time.

Extended Aviation Outlook: Showers and isolated thunderstorms associated with a cold front could bring flight restrictions Wednesday into Thursday.

.MARINE...

Through tonight: A solid northeast surge continues to work southward across the local waters early this morning. We will see solid Small Craft Advisory (SCA) conditions peak across the waters through the morning, with frequent gusts into the 25-30 knot range. SCA's remain in effect for all waters outside of Charleston Harbor where winds should mostly top out in the 15-20 knot range. Seas are expected to mostly peak in the 4-6 ft range across the nearshore waters and the 5-7 ft range across the outer GA waters. Conditions should gradually improve through the day such that the SCA's for the southern SC waters and the nearshore GA waters come down this afternoon. The Charleston County waters will come down next (in the evening), followed last by the outer GA waters which could stick around through much of the night.

The pressure gradient over the local waters will weaken Tuesday as high pressure weakens. Conditions are expected to deteriorate Wednesday as a cold front approaches, with increasing likelihood of Small Craft Advisories. Winds could gust to near 25 knots, with seas building to 3-5 ft. Another system this weekend could bring another period of elevated winds and seas, potentially leading to additional Small Craft Advisories.

Rip Currents: The combination of strong northeast winds and elevated seas will result in a Moderate Risk of rip currents at all beaches today.

.CHS WATCHES/WARNINGS/ADVISORIES...

GA...None. SC...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for AMZ360.

Small Craft Advisory until 5 PM EDT this afternoon for AMZ362- 364. Small Craft Advisory until 5 AM EDT Tuesday for AMZ384.

BRS/BSH