FXUS62 KCHS 111027 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 627 AM EDT Wed Mar 11 2026
.WHAT HAS CHANGED...
The aviation section was updated for the 12z TAFs.
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.KEY MESSAGES...
- 1) Record to near record warmth through tonight.
- 2) Showers and thunderstorms likely Thursday as a cold front
moves through.
- 3) Chances for rain return late weekend into early next week,
followed by notably cooler temperatures Monday night into midweek.
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.DISCUSSION...
KEY MESSAGE 1: Record to near record warmth through tonight.
The western periphery of subtropical high pressure centered well offshore will maintain its influence on the region through tonight. Warm, deep-layered southerly breezes between the high and an approaching cold front will keep the moist and very warm airmass in place through tonight. Highs this afternoon are poised to warm in the upper 80s/lower 90s and it is very possible the records at both KCHS, KSAV and maybe even KCXM could fall, especially with high temperatures over-performing a bit over the past few days from possible contributions from the very dry soil/drought conditions that are in place. Another robust sea breeze will develop along the beaches by early afternoon and trek inland through the rest of the afternoon and into the early evening hours. This will keep a tight thermal gradient across the coastal counties with as much as a 10-15 degree difference between the beaches/barrier island and ~5 miles inland.
Warm conditions will persist into tonight with the atmosphere likely to remain fairly well mixed from strengthening low-level jetting that will occur ahead of the approaching cold front. This will help keep overnight temperatures up a bit which the 11/01z NBM is likely not picking up on. Overnight lows were adjusted based on a blend of hourly temperatures from both the RAP and H3R. This yields lows in the mid 60s with lower 60 at the beaches. The record high minimums could be challenged at all three climate sites. See the Climate section below for more detailed record information.
Rain-free conditions are expected, but a few of the CAMs do spit out a few showers across inland portions of the Lowcountry and the Southern Midlands late afternoon/early evening where some slightly 850 hPa pooling occurs. Confidence for anything measurable is too low to justify a mention at this point, but is something to watch later today.
KEY MESSAGE 2: Showers and thunderstorms likely Thursday as a cold front moves through.
A mid level trough and associated surface cold front will pass through the region on Thursday. Plenty of moisture will be in place with PWats peaking in excess of 1.25 inches, which is near or above 90th percentile of climo for this time of year. Guidance has been consistent in indicating a band of showers with embedded thunderstorms accompanying the front with current timing looking to be Thursday morning into early afternoon. Perusing severe parameters would indicate ample shear for storm organization on the order 50-60 knots, however instability and lapse rates are rather poor. Perhaps if the band ends up being slower, there could be a bit more destabilization, but at this point the potential for severe weather is low. Still, could not rule out a stronger storm or two. This system should be progressive and given widespread severe (D2) and extreme (D3) drought, flooding is not anticipated. Average rainfall amounts are expected to fall in the 0.25-0.75" range, with NBM probability of 12 hr precip > 1" of only 20-40%.
Outside of showers and thunderstorms, winds could become gusty, with gusts to around 25 mph. Conditions should stay shy of Lake Wind Advisory criteria. A significant drop in temperatures will occur behind the front. Thursday night/Friday morning lows will largely fall into the upper 30s to mid 40s, which is a good 20+ degrees cooler than previous nights.
KEY MESSAGE 3: Chances for rain return late weekend into early next week, followed by notably cooler temperatures Monday night into midweek.
The next chance of rain will come Sunday with a warm front, and then Monday with a trailing cold front. Perhaps of bigger note is the cooler temperatures expected behind the cold front. The time period of most concern is Monday night and Tuesday night when lows could drop into the 30s across interior southeast South Carolina and Georgia. Will need to monitor the potential for frost/freeze issues as the growing season has begun. NBM currently has a 30% chance for minimum temperatures less than 32F, mainly Tuesday night/Wednesday morning.
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.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
11/12z TAF Discussion: KCHS/KJZI/KSAV: VFR through 12/12z. Gusts could approach 20 kt at KCHS and KJZI this afternoon. There is a risk for low-level wind shear (LLWS) early Thursday morning, mainly at KCHS and KJZI. The situation looks a bit too marginal to include a mention right now, but trends will be monitored for possible inclusion in later TAF cycles.
Extended Aviation Outlook: Gusty winds and brief flight restrictions in showers and thunderstorms are possible Thursday.
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.MARINE...
Through Tonight: Winds will begin to increase today and especially tonight as the pressure gradient between high pressure well offshore and an approaching cold front tightens. A sea breeze surge will enhance winds along the land/sea interface and Charleston Harbor this afternoon as the sea breeze develops and moves inland. Winds look to peak 15 kt with gusts to 20 kt in the Charleston Harbor. Otherwise, winds will increase to 10 to 15 kt today and 15-20 kt over the South Carolina nearshore and Georgia offshore waters tonight. Seas will build 3-4 ft, except 4-6 ft late in the South Santee-Edisto beach and Georgia offshore legs.
Thursday through Monday: Winds and seas will increase ahead of and behind a cold front, which is expected to push offshore Thursday afternoon. Small Craft Advisories have been hoisted for all coastal waters outside of the Charleston Harbor. Conditions should peak Thursday evening into Thursday night. There remains a low-end potential for gusts to gale force during this time, mainly over the Charleston county and outer Georgia waters, where NBM indicates around a 30% chance of gusts exceeding 34 knots. Spatial extent and duration seems pretty limited, so holding off on any Gale Watches at this time. Winds and seas should vastly improve through the day on Friday, however the Small Craft Advisory for the outer Georgia waters could linger into Friday evening due to 6 ft seas. Next time period of concern is Monday ahead of another cold front. Additional Advisories could be possible.
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.CLIMATE...
Record High Temperatures:
March 11: KCHS: 85/2015 KCXM: 82/1997 KSAV: 87/2015
Record High Minimum Temperatures:
March 11: KCHS: 63/2015 KCXM: 64/2016 KSAV: 64/1974
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.EQUIPMENT...
The KCLX radar is scheduled for radome panel replacement March 14-16, 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
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...None. MARINE...Small Craft Advisory from 6 AM Thursday to 11 AM EDT Friday
for AMZ350. Small Craft Advisory from 2 PM Thursday to 8 AM EDT Friday for AMZ352-354. Small Craft Advisory from 6 AM Thursday to 8 PM EDT Friday for AMZ374.
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