AFD_CHS

FXUS62 KCHS 271822 AFDCHS

Area Forecast Discussion National Weather Service Charleston SC 222 PM EDT Mon Apr 27 2026

.WHAT HAS CHANGED...

A Coastal Flood Advisory has been issued for Charleston and Coastal Colleton Counties until 8PM EDT and the Aviation Section has been updated for the 18Z TAF issuance.

.KEY MESSAGES...

- 1) High pressure will settle over the region and yield breezy,

dry conditions.

- 2) Minor coastal flooding likely with the evening high tide along

the southeast South Carolina coastline.

- 3) Rain chances will increase from mid-week through the

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

.DISCUSSION...

KEY MESSAGE 1: High pressure will settle over the region and yield breezy, dry conditions.

As high pressure continues to build into the region, expect breezy northeasterly flow to persist into the afternoon, before gradually diminishing this evening as the pressure gradient relaxes. The overcast clouds have been stubborn to erode today, and will continue to anticipate some sunshine later this afternoon/evening. Temperatures have been nudged down given the lack of diurnal heating we've seen, and therefore, expect highs in the low 70s across southeast South Carolina and mid to upper 70s across southeast Georgia. PWAT values will drop near 0.5 inches this afternoon as dry air continues to filter into the region. The SCFC Burn Ban remains in effect and the minimum RH values will dip into the 30 to 40% range (away from the coastline) this afternoon with the lowest values across far interior southeast Georgia.

KEY MESSAGE 2: Minor coastal flooding likely with the evening high tide along the southeast South Carolina coastline.

As astronomical tide levels are beginning to rise as we move closer to he upcoming (5/1) full moon, strong northeasterly winds combined with the current tide departure of 1.46 ft will likely cause for minor coastal flooding along the southeast South Carolina coastline with this evening's high tide (~6:15pm). For the evening high tide cycle, the astronomical tide is 5.59 ft MLLW meaning we would need a departure of 1.41 ft the minor coastal flood threshold of 7 ft MLLW. Therefore, with the aforementioned current tide departure, this would mean we will likely see a high tide a little above 7 ft MLLW this evening. Hence, a Coastal Flood Advisory has been issued for Charleston and Coastal Colleton counties until 8PM EDT this evening.

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

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

Another 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 /18Z MONDAY THROUGH SATURDAY/...

18Z TAFs: As the clouds are slow to erode across the region, MVFR cigs in place at KCHS/KJZI/KSAV terminals for a couple more hours. Model guidance continues to suggest conditions returning to VFR somewhere between 20-21Z time period. Breezy northeasterly winds have diminished, and beginning to turn more easterly as we head into the evening.

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

.MARINE...

Through tonight: Northeasterly winds continue to range from 15 to 20 kt with gusts up to 25 kt across the local waters. Thus, Small Craft Advisories remain in effect for the local waters (except for the Charleston Harbor). Expect seas to range from 4 to 6 ft across the nearshore waters and 5 to 7 ft across the outer Georgia waters. Expect marine conditions to gradually improve through the rest of the afternoon and SCA's for the southern South Carolina waters and nearshore Georgia waters will come down this afternoon. Thereafter, the Charleston nearshore waters SCA will come down this evening, followed by the outer Georgia waters later into the night.

Heading into Tuesday, the pressure gradient will weaken over the local waters as the high pressure shifts offshore. Marine conditions are expected to deteriorate Wednesday as a cold front approaches the region, and thus Small Craft Advisories could be needed once again. Winds could gust near 25 knots, with seas building to 3 to 5 ft. Another system this weekend could bring another period of elevated winds and seas, potentially leading to additional Small Craft Advisories.

Rip Currents: A Moderate Risk of rip currents continues at all beaches through the rest of the afternoon given the ongoing strong northeasterly winds and elevated seas.

.CHS WATCHES/WARNINGS/ADVISORIES...

GA...None. SC...Coastal Flood Advisory until 8 PM EDT this evening for SCZ149-

150.

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.

Dennis