FXUS62 KCHS 211120 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 720 AM EDT Sat Mar 21 2026
.WHAT HAS CHANGED...
The Aviation Section has been updated for the 12Z TAF issuance.
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.KEY MESSAGES...
- 1) Quiet weather and warming temperatures through the
weekend.
- 2) A strong backdoor cold front will yield breezy winds and
cooler conditions mid-week.
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.DISCUSSION...
KEY MESSAGE 1: Quiet weather and warming temperatures through the weekend.
Sfc high pressure continues to prevail across the region this weekend, as a modest upper level shortwave slides eastward across the Carolina border later this evening. As noted in the previous discussion, latest CAMs remain in decent agreement that a swath of isolated showers and storms may develop across the Midlands. For us, should see largely dry conditions persist, with perhaps a few sprinkles possible across the northern portions of Dorchester and Berkeley County. Otherwise, expect high temperatures to be roughly 10 degrees above normal through the weekend, as temperatures warm into the mid to upper 80s under mostly sunny skies.
KEY MESSAGE 2: A strong backdoor cold front will yield breezy winds and cooler conditions mid-week.
A strong backdoor cold front will slide across the area Monday night into early Tuesday morning, resulting in breezy winds and cooler, more seasonal temperatures mid-week. Currently have highs in the mid to upper 60s Tuesday warming back into the low to mid 70s by Wednesday. Above normal temperatures then return Thursday as another high pressure builds overhead. In regard to precipitation, PoPs remain capped at 30% with the aforementioned front, thus, limiting our chances for seeing any meaningful rainfall.
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.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions will prevail at KCHS, KJZI, and KSAV through 12Z Sunday.
Extended Aviation Outlook: VFR through Monday. A backdoor cold front is expected to push across the terminals Monday evening, bringing a round of showers and thunderstorms. Behind the front, winds will turn from the northeast and become gusty, especially during the daylight hours on Tuesday.
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.MARINE...
Marine conditions across the coastal waters will remain below Small Craft Advisory conditions this weekend through the daylight hours on Monday. High pressure should generally support southwest winds between 10 to 15 kts with gusts around 20 kts. Wave heights should range between 3-5 ft.
By Monday evening, a backdoor cold front should plunge southward across the marine zones. A tightening pressure gradient and CAA should result in gusty NNE winds and building seas early next week. In the wake of the cold front Monday evening, winds across the coastal waters are forecast to turn from the NE and strengthen to around gales by daybreak Tuesday morning. Gale gusts are possible well into the daytime hours on Tuesday. A Gale Watch could be needed for the SC and GA Atlantic waters. In addition, wave heights are forecast to peak on Tuesday, ranging from 6-8 ft within 20 NM and 8- 10 ft beyond 20 NM.
On Wednesday, a ridge of high pressure should result in decreasing winds across the coastal waters. As a result, wave heights should gradually diminish, however, 6 ft seas may linger over the outer GA waters into Wednesday.
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.CLIMATE...
Record High Temperatures:
March 22: KCHS: 88/2011
March 23: KCHS: 87/1995
March 27: KCHS: 87/2021 KCXM: 81/2021 KSAV: 89/2021
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...None. MARINE...None.
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NED/SST