FXUS62 KCHS 121844 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 244 PM EDT Thu Mar 12 2026
.WHAT HAS CHANGED...
Rainfall timing for this afternoon, and timing of strong backdoor cold front this evening, have been refined.
&&
.KEY MESSAGES...
- 1) Gusty winds continue through this evening, with cooler air
filling in behind a cold front.
- 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: Gusty winds continue through this evening, with cooler air filling in behind a cold front.
A band of mainly light rainfall over the immediate coast early this afternoon will shift offshore through mid-afternoon. The initial weak cold front is crossing the area behind the rainfall, and will slide over the waters by late afternoon. Winds become NW, but remain moderate for several hours before a stronger backdoor cold front crosses the area in response to high pressure rapidly building into the Mid-Atlantic. Strong CAA in the wake of this cold front will bring gusty winds this evening and into the overnight hours, with a Lake Wind Advisory remaining in effect, and a mix of Small Craft Advisories and Gale Warnings over the inshore and coastal waters.
Clearing skies and weakening winds through the overnight and early morning hours will likely bring several hours of favorable radiational cooling before sunrise. Temperatures west of US Hwy 17 and north of I-16 could briefly dip into the mid 30's around sunrise, and some patchy frost is possible. However, very limited duration and coverage do not warrant a Frost Advisory at this time.
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 /18Z THURSDAY THROUGH TUESDAY/...
12/18z TAF Discussion: KCHS/KJZI/KSAV: Lingering rainfall through early afternoon will give way to dry conditions and gradual clearing mid-to-late afternoon. VFR is expected to prevail, though and MVFR ob or two cannot be ruled out as the drier air works in initially. Moderate to breezy NW winds develop this afternoon, but become gusty N to NE this evening behind a backdoor cold front that will quickly cross the area.
High pressure builds in quickly through the overnight hours, with the weaker gradient and limited moisture resulting in VFR conditions prevailing into Friday.
Extended Aviation Outlook: Brief flight restrictions are possible in showers and thunderstorms Sunday and Monday. Gusty winds also possible on Monday.
&&
.MARINE...
Through Tonight: Breezy SW winds early this afternoon become NW behind and initial cold front that will cross the waters mid- to-late afternoon. However, the backdoor cold front that will cross the waters early this evening is expected to user in the stronger winds as high pressure quickly builds over the Mid- Atlantic. Wind gusts to 30 kts likely across all waters, with gusts up to 35 kt and a Gale Warning for the Charleston County coastal waters and offshore GA waters.
The gradient will begin to weaken through the early morning hours as the high begins to shift closer to the area, but SCA conditions still persist through daybreak. Seas peak at 5-8 ft early Friday, greatest beyond 15 nm offshore where the N/NE winds have more fetch and are able to build some medium period swell.
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 until 11 PM EDT this evening for SCZ045. MARINE...Small Craft Advisory until 11 PM EDT this evening for AMZ330.
Gale Warning until 2 AM EDT Friday for AMZ350. Small Craft Advisory until 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.
&&
$$
CEB