AFD_CHS

FXUS62 KCHS 260759 AFDCHS

Area Forecast Discussion National Weather Service Charleston SC 359 AM EDT Thu Jun 26 2025

.SYNOPSIS...

A hot and humid air mass will remain across the region into early next week. A slow moving cold front may push over the region by the middle of next week.

.NEAR TERM /THROUGH TONIGHT/...

Prior to daybreak: A few showers/thunderstorms could continue across far southern zones (primarily McIntosh County) early morning where a boundary from previous convection has provided a zone of moisture convergence and modest instability (SBCAPE around 2500 J/kg) resides. This activity is expected to remain sub-severe within a weakly sheared environment, but brief downpours could pose some impacts to those driving along I-95 near the Altamaha River. Activity should eventually drift south and slightly inland with time, keeping most areas precip-free heading through daybreak.

Today: Aloft, a broad mid-upper lvl low will meander across the Southeast, remaining primarily centered across Florida and Georgia and forcing the mid-upper lvl ridge further north and inland. At the sfc, the local area will remain nestled along the western edge of the Atlantic high while weak troughing develops inland to the area during the afternoon. The mid-upper low will be the primary contributor to forcing necessary for few to scattered showers and thunderstorms this afternoon, as lobes of h5 vort energy advect across an inland moving sea breeze and potentially lingering boundaries from convection experienced during the night. Conditions could become marginally supportive for a few strong and/or isolated severe thunderstorms capable of damaging wind gusts this afternoon into early evening given SBCAPE around 3000 J/kg, low-lvl lapse rates between 8-8.5 C/km, DCAPE values around 1000-1200 J/kg and PWATs near 1.75 inches. However, weak shear/wind fields suggests convection to be more loosely organized, less widespread, and generally more pulse type in nature away from the coast. The Storm Prediction Center has much of Southeast South Carolina and Southeast Georgia under a Marginal Risk for severe weather today.

Temps will start off cooler than experienced the previous few days due to late night convection, and should also result in a period of precip-free conditions across most zones into late morning hours. However, the atmosphere is expected to recover, with strong sfc heating under sunny/mostly sunny skies leading to afternoon highs in the low-mid 90s away from coastal areas. These temps along with sfc dewpts in the low-mid 70s will produce another warm and humid day, but heat index values should be noticeably less than the previous day, peaking in the l00-104 degree range. A Heat Advisory is not anticipated at this time.

Tonight: A few showers/thunderstorms could linger into early evening hours with h5 shortwave energy traversing the local area aloft and modestly unstable conditions persisting, but activity should generally wane with the loss of diurnal heating, remain sub-severe, and drift further west out of the local area with a sea breeze. Winds should decouple shortly thereafter, leading to light/calm winds away from the beaches for a bulk of the overnight period. Temps should dip into the upper 60s/lower 70s well inland to mid- upper 70s near the coast.

.SHORT TERM /FRIDAY THROUGH SUNDAY/...

An upper-lvl ridge situated over the western Atlantic will continue to breakdown throughout the weekend. Simultaneously, a broad low over the Deep South will continue to advect rich moisture into the region with PWAT values ranging from 1.75 to 2.0 inches. This will be more than enough moisture to spark up some showers and thunderstorms each afternoon as the sea breeze pushes inland. Due to temperatures in the low to mid 90s and dewpoints in the low to mid 70s throughout the weekend, moderate instability should develop and it's possible to see strong to severe thunderstorms each afternoon. In addition, SPC has highlighted the far interior Southeast Georgia counties in a marginal risk for Friday with the primary concern being locally damaging wind gusts. Overnight lows will remain mild and only dip into the low to mid 70s (with warmer temperatures closer to the beaches).

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...

This current pattern will be slow to change as this weak upper-lvl low continues to meander across the Deep South before eventually dissipating early next week. With an expansive field of moisture remaining over the Southeast combined with high temperatures in the low to mid 90s, moderate instability (~2000 J/kg) could very well build each afternoon. Ensembles continue to indicate daily rain chances through the period with storm activity gradually increasing each day. By the middle of next week, recent guidance indicates a slow-moving cold front may glide through the region. Thus, thunderstorms could easily develop along this boundary if it makes it this far into the region. Temperatures will remain slightly above normal for this time of the year.

.AVIATION /07Z THURSDAY THROUGH MONDAY/...

VFR conditions are expected at CHS/JZI/SAV terminals through 06Z Friday. However, a few showers and/or thunderstorm could impact any terminal this afternoon, leading to TEMPO flight restrictions. Probabilities remain too low to include in the latest TAF issuance.

Extended Aviation Outlook: VFR will mainly prevail throughout the period, however brief flight restrictions are possible within showers and thunderstorms that develop in the afternoon and/or evening.

.MARINE...

Today and Tonight: Local waters will remain along the western periphery of an Atlantic high while weak troughing develops well inland. Conditions will remain below Small Craft Advisory thresholds during this time frame, but a broad mid-upper lvl low could spawn showers and thunderstorms across local waters during the day and night, producing gusty winds and elevated seas. Outside convection, southwest winds in the 5-10 kt range will gradually turn south and peak between 10-15 kt this afternoon, and perhaps gust a bit higher along the immediate coast where a sea breeze develops and shifts inland. Winds should tip back more south-southwest by late evening, then remain around 10 kt or less during the night. Seas will generally range between 1-2 ft today, then gradually build 1 ft overnight.

Friday through Monday: Expect generally south-southeasterly winds at 5 to 10 kt to prevail throughout the period. It could become a bit gusty each afternoon with gusts up to 15 to 20 kt as the seabreeze pushes inland (gusts strongest across the immediate coastline and the Charleston Harbor). Seas will be 2 to 3 ft. Otherwise, no marine concerns expected.

Rip Currents: A 1.5 ft, 8 second swell will impact the beaches along with a 10-15 kt onshore wind today. Given these conditions are similar to the last couple days with several rip currents reported along Tybee Island, GA, a Moderate Risk for rip currents is in place along Georgia beaches through this evening.

.CHS WATCHES/WARNINGS/ADVISORIES...

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

NEAR TERM...DPB SHORT TERM...Dennis LONG TERM...Dennis AVIATION...Dennis/DPB MARINE...Dennis/DPB