textproduct: Charleston

WHAT HAS CHANGED

All Key Messages and sections have been updated.

KEY MESSAGES

- 1) Showers and a few thunderstorms will move through the area later this morning through early afternoon. Gusty winds and falling temperatures are likely with hazardous conditions on Lake Moultrie.

- 2) Chances for rain return late weekend into early next week.

- 3) Notably cooler temperatures are expected Monday night into the middle of next week, with potential for a frost/freeze across interior southeast South Carolina and Georgia.

DISCUSSION

KEY MESSAGE 1: Showers and a few thunderstorms will move through the area later this morning through early afternoon. Gusty winds and falling temperatures are likely with hazardous conditions on Lake Moultrie.

Impressive warm sector conditions are in place this morning with temperatures still well into the 70s at 12/05z. Temperatures will change little through daybreak with a strong low-level jet helping to keep the atmosphere well mixed. Gusty winds will impact many areas through daybreak with the strongest gusts likely occurring along parts of the Charleston Tri-County into southern Colleton County where gusts 30-35 mph could occur coincident with the strongest portion of the 1000-925 hPa low- level jet.

A large band of showers/tstms is moving across the Deep South this morning. This band is timed to reach western areas after daybreak and quickly pass west-east before exiting the coast with the cold front by early afternoon. The frontal structure looks anafrontal with the heaviest/strongest convection likely occurring near/just ahead of the cold front itself followed by 2-3 hours of more stable shower activity in the deepening cold sector. Pops near 100% were highlighted for the South Carolina Lowcountry and Southeast Georgia with rain chances quickly dropping through the afternoon. Instability ahead of the front looks to remain fairly limited with guidance only showing about 500 J/kg of MLCAPE in the warm sector. While the degree of mixed-layer instability is tempered there looks to be enough to support a few tstms, especially given the amount of DPVA noted ahead of the dampening shortwave that will pass through later in the day. There could even be a few loosely organized convective segments given 0-6km bulk shear values around 50 kt, but the limited overall instability should mostly curtail the overall severe weather potential. Still, a strong tstm or two with gusty winds 40-50 mph could occur.

Outside of convection, gusty winds will persist through the day. Conditions on Lake Moultrie should reach hazardous levels later this morning and continue through the evening hours with the onset of post frontal cold air advection. A Lake Winds Advisory is in effect from 9 AM until 10 PM for northwest winds of 15-25 kt with gusts 25-30 kt and waves 2-3 ft.

Temperatures will be closely tied to frontal timing today. Highs will likely occur this morning with temperatures slowly falling through the afternoon with the onset of cold air advection behind the cold front. Highs look to peak in the lower-mid 70s with a few upper 70s possible in the I-95 corridor between Savannah-Darien. Conditions will quickly clear this afternoon and evening with colder conditions dominating tonight. Lows will drop into the mid-upper 30s inland to the upper 40s/lower 50s at the beaches where northeast winds will have a bit of a warming influence. There could even be some patchy frost that forms just before daybreak across far northern portions of Allendale, Hampton, Colleton, Dorchester and Berkeley Counties. Durations look pretty brief and impacted areas fairly isolated, so a Frost Advisory will not be issued.

KEY MESSAGE 2: Chances for rain return late weekend into early next week.

A coastal trough off the Southeast coast is expected to lift north as a warm front on Sunday. Weak vort energy and deep moisture in place could result in scattered to numerous showers developing through the day. Ensemble means then indicate a seasonally strong mid level trough shifting into the eastern U.S. Sunday night into Monday. An associated surface low will bring a trailing cold front through southeast South Carolina and southeast Georgia during the day. This will bring a risk for additional showers and thunderstorms to the area. Ample deep layer shear on the order of 40-50 kt looks to be present for storm organization and with some weak instability, we will need to monitor for the potential for a couple stronger storms. CSU- Machine Learning severe probability forecast hints at this possibility as well.

KEY MESSAGE 3: Notably cooler temperatures are expected Monday night into the middle of next week, with potential for a frost/freeze across interior southeast South Carolina and Georgia.

Following passage of a cold front on Monday, drastically cooler temperatures are expected through the middle of next week. Of most concern is the overnight temperatures Monday night and again Tuesday night. Locations across the interior could see temperatures dip well into the 30s and cause frost/freeze issues now that the growing season has begun. The coldest of the two nights is expected to be Tuesday night into Wednesday morning. NBM indicates roughly a 30-40% chance of minimum temperatures less than 32F, mainly west of I-95 and north of I-16. Frost Advisories and/or Freeze Watches and Warnings could be needed.

AVIATION /04Z THURSDAY THROUGH MONDAY/

12/06z TAF Discussion: KCHS/KJZI/KSAV: An area of showers/tstms will impact the terminals this morning, roughly 16-19z at KCHS/KJZI and 15-18z at KSAV. Thunderstorm probabilities are too low to mention at this time, but a period of MVFR vsbys/cigs appears likely as a cold front shifts offshore. Expect rapid clear and a return to VFR by mid-late afternoon with mostly clear conditions overnight. Gusty winds will persist through late afternoon.

Extended Aviation Outlook: Brief flight restrictions are possible in showers and thunderstorms Sunday and Monday. Gusty winds also possible on Monday.

MARINE

Through Tonight: The risk for gales have increased since yesterday with strong cold air advection poised to bring frequent gusts to 35-40 kt across the Charleston County over the offshore waters beyond 20 NM. Gale Warnings have been issued for the South Santee-Edisto Beach nearshore and Georgia offshore legs. Small Craft Advisories are in effect for all remaining waters. The highest winds will occur late this afternoon through late evening when the period of strongest cold air advection will occur. Winds will remain elevated through the night with pinched gradient conditions developing between high pressure to the north and a frontal low that will develop along the front later today/tonight. Max seas will peak

Friday through Tuesday: Lingering 6 ft seas will support the Small Craft Advisory continuing for the outer GA waters through much of the day Friday, but overall conditions will be improving. The next time period of concern is Sunday night into Monday with the approach of a cold front. Another round of advisories appear likely for at least portions of the waters, which could persist through Monday night following FROPA. Winds and seas should subside on Tuesday.

EQUIPMENT

The KCLX radar is scheduled for radome panel replacement March 16-19, 2026. The radar will be down during this time. Users are encouraged to use data from the following nearby radar sites during the maintenance outage:

KCAE - Columbia, SC KLTX - Wilmington, NC KJAX - Jacksonville, FL KVAX - Moody AFB, GA KJGX - Robbins AFB, GA

CHS WATCHES/WARNINGS/ADVISORIES

GA...None. SC...Lake Wind Advisory from 9 AM this morning to 10 PM EDT this evening for SCZ045. MARINE...Small Craft Advisory from 9 AM this morning to 10 PM EDT this evening for AMZ330. Gale Warning until 2 AM EDT Friday for AMZ350. Small Craft Advisory from 6 AM this morning to 9 AM EDT Friday for AMZ352-354. Small Craft Advisory until 6 PM EDT this evening for AMZ374. Gale Warning from 6 PM this evening to 2 AM EDT Friday for AMZ374.