AFD_CHS

FXUS62 KCHS 261207 AFDCHS

Area Forecast Discussion National Weather Service Charleston SC 707 AM EST Thu Feb 26 2026

.WHAT HAS CHANGED...

The Aviation Section has been updated to reflect the 12Z Thursday TAF issuance.

.KEY MESSAGES...

- 1) Strong winds and rough waves expected to bring hazardous conditions across Lake Moultrie today.

- 2) A passing front will result in widespread rainfall from late tonight through Saturday.

.DISCUSSION...

KEY MESSAGE 1: Strong winds and rough waves expected to bring hazardous conditions across Lake Moultrie today.

Conditions will slowly deteriorate across Lake Moultrie mid-late morning as the pressure gradient between high pressure offshore and an approaching cold front occurs across the region. Although water temps remain in the lower 50s across the lake, nearby sfc heating across land is likely to support mixing into 35-40 kt low-lvl wind fields. As a result, a Lake Wind Advisory remains in effect this morning into late afternoon for southwest winds 15-20 kt with gusts around 25 kt during the peak of the event. Gusts should be highest along the lakeshore.

KEY MESSAGE 2: A passing front will result in widespread rainfall from late tonight through Saturday.

Aloft, expect broad mid-lvl trough to continue to slide into the region this morning, and then shift more towards the Eastern Seaboard overnight into Friday. Simultaneously, the low-lvl jet is expected to continue to strengthen across the region this morning as well and yield breezy southwesterly winds throughout the evening, before it advances off the Mid-Atlantic coastline tonight. At the surface, a low will track northeastward across the mid-South throughout the afternoon with an associated cold front. This aforementioned low-lvl jet will also advect a good amount of moisture into the region with PWATs climbing up to 1.3-1.5" by this afternoon. Some isolated showers could develop as early as this morning across the far inland counties, before slowly becoming more widespread in the overnight and into Friday. Some weak (MUCAPE < 500 J/kg) instability could be present ahead of the front overnight, therefore the mention of thunderstorms has been noted in the forecast. However, the severe risk remains quite low as the lack of sunshine will hinder thunderstorm potential. Most of the rainfall will be contained to Friday with rainfall totals ranging from 1-1.75 inches (over a 48-hr period) with the highest amounts across inland southeast Georgia. The trend continues to suggest that flooding will not be a concern esp. with the ongoing drought conditions. Hi-res model guidance indicates that rainfall should clear off the coastline on Friday night, however there is a chance of some lingering showers esp. across the coastal counties into late Sat. morning. High temps. will be a few degrees above normal with temps. ranging from upper 60s to low 70s throughout the period.

.AVIATION /12Z THURSDAY THROUGH MONDAY/...

CHS/JZI: TEMPO MVFR conditions are possible between 12-13Z with a band of light showers this morning (more likely at CHS). Otherwise, VFR conditions will prevail at the terminals through 21Z Thursday. However, southwest winds should become quite gusty late morning and afternoon, generally in the 20-25 kt range. Light to moderate showers could then bring MVFR conditions at both terminals late afternoon/early evening where PROB30 groups are in place from 21Z-01Z. Shower activity becomes more numerous late in the TAF period, which could produce additional rounds of MVFR or lower cigs/vsbys. A few thunderstorms are also possible late tonight/early Friday. PROB30 groups from thunderstorms and MVFR conditions have been included between 08-12Z Friday.

SAV: VFR conditions will prevail through 00-02Z Friday. However, southwest winds should become quite gusty late morning and afternoon, generally in the 20-25 kt range. Light to moderate showers could then bring MVFR conditions Thursday evening into early Friday, which is marked by a PROB30 group between 03-07Z Friday. Additional shower activity is anticipated early Friday and could produce MVFR conditions late in the TAF period, but confidence remains too low to include in the latest TAF issuance.

Extended Aviation Outlook: A cold front will bring flight restrictions late tonight into Friday. Occasional flight restrictions could persist into Saturday, however conditions should improve back to VFR Saturday afternoon through Sunday.

.MARINE...

Today and Tonight: After a lull in winds across coastal waters early morning, expect marine conditions to deteriorate during the day as the pressure gradient becomes enhanced between high pressure extending across the western Atlantic and a cold front approaching the region from west-northwest through tonight. Although a warm air advection setup is anticipated during this time frame, the strengthening pressure gradient and 35-40 kt 1000mb geostrophic wind field suggests south/southwest winds becoming quite gusty across all waters late morning and afternoon, supporting Small Craft Advisories across all waters this morning and afternoon. Winds/seas will remain strongest/largest across SC nearshore waters and offshore GA waters with gusts up to 25-30 kt and seas as large as 4-7 ft. Nearshore Georgia waters could experience slightly weaker winds and smaller waves given less favorable low-lvl mixing across cooler waters away from the Gulf Stream. Should trends remain weaker, the Small Craft Advisory across nearshore GA waters could be dropped several hours prior to remaining coastal waters.

Friday through Monday: A cold front is anticipated to approach local waters early weekend, likely shifting offshore by Friday night, then will be followed by high pressure building and persisting across the region through the weekend. This pattern should support conditions that remain well below Small Craft Advisory levels through the weekend, prior to stronger high pressure attempting to wedge south across the region early next week. Should this scenario unfold, winds/seas will likely increase/build across local waters and could lead to additional Small Craft Advisories next week.

.CHS WATCHES/WARNINGS/ADVISORIES...

GA...None. SC...Lake Wind Advisory until 5 PM EST this afternoon for SCZ045. MARINE...Small Craft Advisory until 5 PM EST this afternoon for AMZ330.

Small Craft Advisory until 7 PM EST this evening for AMZ350- 352-374. Small Craft Advisory until 4 PM EST this afternoon for AMZ354.

Dennis/DPB