AFD_CHS

FXUS62 KCHS 292326 AFDCHS

Area Forecast Discussion National Weather Service Charleston SC 626 PM EST Sat Nov 29 2025

.SYNOPSIS...

High pressure will prevail through the weekend, and then a storm system should pass through the region late Monday into Tuesday. High pressure returns for the middle to end of next week.

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...

Early this evening: Surface analysis shows high pressure centered near the Delmarva, ridging down the east side of the Appalachians. Just offshore, a coastal trough is taking shape, with radar imagery showing a few light returns starting to pop up around 50-60 miles offshore of the Chatham/Beaufort county coast. Overnight, the center of the high will push off to the northeast and the inland ridge will start to break down. This will allow the coastal trough to buckle back towards the coast. Hi-res model guidance suggests that shower activity over the coastal waters will steadily increase overnight within the coastal trough, and will gradually migrate closer to the coast. Late tonight we could even see a few showers move onshore primarily along the SC coast. Temperatures won't be quite as cold as the last two nights. Look for lows in the mid to upper 30s inland, ranging to the mid to upper 40s along the coast.

.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...

Sunday: As the weak coastal trough traversing across the Great Lakes region mixes out ahead of an approaching cold front, southwesterly flow aloft will yield PWAT values between 1 to 1.5" by the afternoon. Additionally, temperatures should be able to return to the upper 60s to low 70s in the WAA regime. Isentropic lift may result in some weak showers in the morning, however the chance of this remains quite low. Expect cloud cover to increase through the evening and into the overnight, with lows dropping into low 40s inland and the mid 40s to low 50s near the coastline.

Monday and Tuesday: As the front pushes offshore Monday morning, expect surface high pressure to build into the region from the north throughout the day. This feature will produce temperatures back down into the mid 50s to mid 60s, with the warmest temps. across southeast Georgia on Monday. Some drier air is expected to filter in behind the front, however this will only last momentarily as the next system approaches. A surface low should develop across the Gulf and move rather quickly towards the region from the southwest late Monday evening into Tuesday. This will yield a surge of moisture and PWATs will ramp up to 1.5-1.75" overnight. Simultaneously, chances of rainfall will also increase with the greatest chance on Tuesday morning into the early afternoon as the low passes through the region. However, despite PWAT values approaching the 90th percentile, rainfall amounts look to remain around 0.50 to 1.0 inches, with the highest across the interior counties of SOuth Carolina. This will likely add some relief to the ongoing drought conditions across the region.

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...

After the surface low passes through the region, chances for rainfall dwindle with surface high pressure building into the region behind the system and ensemble guidance suggests the upper-lvl flow becomes more zonal. This pattern will produce temperatures near normal throughout the period. Expect surface high pressure to move offshore rather quickly as another system approaches the region from the southwest. However, model consensus remains rather poor on the timing of this system for the the end of the week.

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...

VFR conditions are expected to prevail at KCHS, KJZI, and KSAV through 00z Monday. Stratocumulus with bases between 2.5-3.5 kft will likely spread onshore through the night and into Sunday morning. Can't completely rule out a short period of MVFR ceilings at all 3 TAF sites, but overall VFR.

Extended Aviation Outlook: Low-lvl moisture will increase ahead of an approaching surface low, this will likely yield flight restrictions (in terms of low ceilings) as early as Sunday night. However, the higher chance of flight restrictions will occur on late Monday evening into Tuesday after as the aforementioned low passes through the region. This system will likely produce low ceilings and reduced vsbys.

.MARINE...

Tonight: High pressure to our northwest this evening will shift away, while a surface trough just offshore strengthens and moves closer to the coast. Additionally, a cold front will approach from the west overnight. This synoptic setup will bring sustained NE winds 15-20 kt this evening, then veering overnight, and easing to around 10 kt by daybreak Sunday. Seas 4-5 ft this evening should subside to 3-4 ft overnight.

Sunday through Wednesday: Expect weak southeasterly winds to spin towards the northeast by Monday as a cold front passes through the local waters on Monday morning. These northeasterly winds will likely increase throughout Monday as a surface low approaches the region from the southwest, with speeds 10 to 15 kts and gusts up to 20 kts. It's also possible to see some 6 footers in the Charleston nearshore waters as early as Monday evening. As the surface low passes through the region on Tuesday, winds will out of the veer the southwest and increase a touch, but remain sub-advisory in the forecast. However, a reinforcing shot of south-southeasterly swell mixes into the waters on Tuesday and seas increase to 5 to 7 ft in the South Carolina nearshore and 6 to 8 ft in the outer Georgia waters on Tuesday afternoon. Therefore, Small Craft Advisories will likely be needed on Tuesday afternoon into the overnight. Afterwards, the swell looks to ease back as high pressure returns to the Atlantic waters on Wednesday and conditions rapidly improve.

.CHS WATCHES/WARNINGS/ADVISORIES...

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

NEAR TERM...BSH SHORT TERM... LONG TERM... AVIATION...BSH MARINE...