AFD_CHS

FXUS62 KCHS 031841 AFDCHS

Area Forecast Discussion National Weather Service Charleston SC 141 PM EST Sat Jan 3 2026

.SYNOPSIS...

A storm system will move through our region today, yielding widespread showers and some thunderstorms. High pressure and drier conditions return thereafter, with gradually warming temperatures.

.NEAR TERM /THROUGH TONIGHT/...

This Afternoon: Aloft, a strong h5 shortwave will dig east-southeast across the Deep South and northern Gulf, helping sharpen elongated sfc low pressure under a subtropical jet, and eventually driving the low pressure system eastward across the local area late day. A warm front already positioned across Southeast South Carolina has been the primary focus of light to moderate rains earlier today with rainfall accumulations in the 0.50 to 1 inch range. Near and north of the warm front, temps remain cooler and should only reach the upper 50s/around 60 degrees, especially away from the coast. Given widespread clouds and lack of substantial sfc heating anticipated, precip will likely remain in the form of light to perhaps moderate rain and/or showers across northern areas this afternoon, especially across the Tri-County Area.

South of the warm front, precip activity has been more sparse early, but light southerly winds continue to advect warm and moist air into the vicinity ahead of the arriving low pressure system, setting up for scattered to widespread showers along with a few thunderstorms early/mid afternoon. There is some indication that a few thunderstorms could become strong and/or perhaps severe south of the warm front, primarily across Southeast Georgia where 0-6 km bulk shear around 30-35 kt coincides with an axis of SBCAPE in the 250-500 J/kg range during maximum daytime heating (highs in the upper 60s). However, cloud cover and/or showers prior to and during peak heating hours could substantially limit this concern. Latest radar imagery does indicate a swath of rain/showers crossing the Altamaha River into southern most zones along with gusty showers elsewhere north into southern portions of Southeast South Carolina, but the window for stronger activity is becoming short. Should an isolated severe thunderstorm develop, damaging wind gusts will be the primary concern this afternoon, although an isolated tornado can not be ruled out prior to cold fropa given favorable wind fields/low-lvl shear. The Storm Prediction Center continues to mark Southeast Georgia into southern Southeast South Carolina in a Marginal Risk for severe weather today.

Rainfall totals associated with the passing low pressure system should average in the 0.25 to 0.75 inch range. However, some spots around 1 inch are possible, such as those already observed near the warm front across the Tri-County Area and perhaps for locations that experience a thunderstorm south of the front this afternoon. While there could be a minor flood threat for urbanized areas with thunderstorm activity along and south of a line from around Statesboro, GA to around Beaufort, SC, the overall flood threat is low given the short window of time for precip activity.

Tonight: The low pressure system and associated cold front will be offshore by early evening, shifting further east and away from the coast overnight. Sfc winds will turn more northerly as the system departs the area and precip chances will come to an end this evening, while dry and colder air begins to usher into the area. However, low stratus should linger across most areas through the night. Low temps are forecast to dip into the upper 30s north/inland to low-mid 40s closer to the coast and across much of Southeast Georgia.

.SHORT TERM /SUNDAY THROUGH TUESDAY/...

The mid-levels will consist of northwest flow overhead on Sunday. It'll gradually transition to zonal flow by Tuesday. At the surface, High pressure will pass to our north on Sunday, then shift well offshore by Tuesday. The periphery of the High will bring our land areas dry conditions, with a mix of sun and clouds. High temperatures will be at or slightly below normal on Sunday due to northerly surface winds and cold air advection. However, high temperatures will quickly rebound to above normal Monday, rising even further on Wednesday.

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

The periphery of surface High pressure will continue to bring our area dry conditions through the end of the week. The big story will continue to be the high temperatures well above normal each day, along with the mild overnight temperatures.

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...

KCHS/KJZI: Prevailing IFR are expected this afternoon with low clouds and light/moderate showers, followed by additional low clouds tonight and through about 14Z Sunday morning. There are some indications that fog could develop late tonight, posing additional vsbys restrictions, but confidence is too low to include in the 18Z TAF issuance. VFR conditions are then expected late Sunday morning through 18Z Sunday.

KSAV: MVFR conditions will prevail this afternoon into early evening. Additionally, wind gusts up to 15-20 kt are possible with thunderstorms temporarily between 18Z-22Z today. IFR conditions are then expected to arrive by 01Z Sunday and persist through about 15Z Sunday. There are some indications that fog could develop late tonight, posing additional vsbys restrictions, but confidence is too low to include in the 18Z TAF issuance. VFR conditions should return late Sunday morning and persist through 18Z Sunday.

Extended Aviation Outlook: VFR.

.MARINE...

This Afternoon through Tonight: Southwest flow will prevail ahead of an approaching cold front and associated sfc low this afternoon into early evening. In general, wind gusts should top out near 15-20 kt, but could gust to around 25 kt across outer Georgia waters where low- lvl mixing is stronger. Seas should also build to 2-4 ft across nearshore waters and 4-6 ft across outer Georgia waters. A Small Craft Advisory remains in effect across outer Georgia waters based on these current and/or expected conditions, and will likely persist into overnight hours as winds turn northwest, then more northerly behind the cold front and associated sfc low shifting further offshore. The pressure gradient should begin to gradually relax late night, allowing wind/sea conditions to drop below Small Craft Advisory levels across local waters.

Extended Marine: High pressure will pass to our north on Sunday, then shift offshore afterwards. This will lead to rather tranquil conditions for the coastal waters, with no Small Craft Advisories expected.

.TIDES/COASTAL FLOODING...

Winds shift to the north-northeast Sunday morning behind a departing low pressure system, leading to a favorable wind direction for greater tidal departures during the Sunday morning high tide cycle in the Charleston Harbor (at 829 AM). The forecast notes minor coastal flooding with a predicted water level of 7.1 ft MLLW as of now. Therefore, a Coastal Flood Advisory could be needed on Sunday morning.

.CHS WATCHES/WARNINGS/ADVISORIES...

GA...None. SC...None. MARINE...Small Craft Advisory until 3 AM EST Sunday for AMZ374.

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