FXUS62 KCHS 151837 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 237 PM EDT Thu Oct 15 2026
.WHAT HAS CHANGED...
All sections have been updated.
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.KEY MESSAGES...
- 1) Above normal temperatures and dry conditions will prevail through Friday.
- 2) Expect gusty winds and temperatures well below normal this weekend behind a strong cold front.
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.DISCUSSION...
KEY MESSAGE 1: Above normal temperatures and dry conditions will prevail through Friday.
Continued warm and dry conditions today and Friday as a ridge of high pressure slides across the region from west to east. At the surface, high pressure combined with h925 temperatures in the 20-22 deg C range will result in afternoon highs peaking in the mid to upper 80s today. This is within reach of a few record high temperatures across the region, with the individual records at our climate sites in the climate section at the bottom of AFD.
Similar to the past couple mornings, patchy shallow ground fog may develop during the late overnight hours into the morning. Inland, we'll likely reach cross over temperatures with max expected dew points today in the mid to upper 60s and overnight lows in the upper 50s to mid 60s, resulting in cross-over temperatures reached/exceeded. Along the coast, fog is a bit more uncertain as overnight lows approach cross-over temperature but don't exceed them. Probabilities for visibilities below 5 miles are in the 20 to 30% range, with probabilities for a mile dropping below 15%.
After any fog mixes out, above normal temperatures build into Friday afternoon. While h925 temperatures remain in the 20-22 deg C range producing highs in the mid to upper 80s across the region, winds become gusty in the afternoon with gusts in the teens as a cold front approaches from the west.
KEY MESSAGE 2: Expect gusty winds and temperatures well below normal this weekend behind a strong cold front.
Friday: A strong cold front will approach from the northwest this weekend, likely passing across the local area Friday night into early Saturday. Ahead of the front, another warm day is expected with temperatures well above normal, generally peaking in the mid- upper 80s. Temps should fall a few degrees short of record warmth. Latest guidance indicates modest moisture supply with and post fropa during overnight hours as well, but the duration suggests very little if any precip accumulation across northern areas. Post fropa, northwesterly winds develop, becoming breezy after midnight, but well short of any land-based headline criteria (gusts to 15-20 mph). The exception could be across Lake Moultrie, where mid 70s water temps promote ample mixing into 30 kt low-lvl wind fields. A Lake Wind Advisory could be needed for Lake Moultrie prior to daybreak Saturday.
Saturday and Sunday: A noticeably cooler airmass will be in place as high pressure builds behind a departing cold front. Afternoon highs and overnight lows will be some 20-25 degrees colder than the previous day, struggling to reach the mid-upper 60s inland and lower 70s elsewhere Saturday afternoon, then low-mid 60s Sunday afternoon. Overnight lows should dip into mid 40s inland to low-mid 50s near the coast.
Breezy north/northeasterly winds will be the main issue over the weekend, as strong cold air advection associated with building high pressure promotes mixing into enhanced low-lvl wind fields (1000mb geostrophic winds 30-40 kt). Wind gusts up to 20-30 mph will be common Saturday and Sunday for most areas, with perhaps some slight enhancement along the beaches, upwards to 30-35 mph. Conditions appear to fall short of Wind Advisory criteria, although winds could become rather gusty on bridges near the coast. The exception will remain across Lake Moultrie where warmer lake waters promote stronger low-lvl mixing and likely support Lake Wind Advisory conditions Saturday into Sunday.
On Monday, sfc high pressure should persist across the region, but start to show signs of weakening across the Southeast heading into the middle of next week. However, northerly sfc flow remains and likely slows airmass modification early to mid week, perhaps due to low pressure also attempting to develop off the Mid-Atlantic coast. Temperatures should gradually warm mid-late week, but could remain a few degrees below normal (mid-upper 70s for highs).
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.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Mostly clear skies are expected this afternoon, though a cu field can't be ruled out near 5kft as is observed on satellite. Otherwise expect light winds shifting to become out of the south later today, becoming weakly southwesterly overnight. Chances for patchy shallow ground fog increase during the late overnight hours. Probabilities for visibilities below 5 miles are in the 20 to 30% range, with probabilities for a mile dropping below 15%.
Extended Aviation Outlook: VFR conditions are expected at CHS/JZI/SAV terminals. However, breezy north/northeasterly winds are likely at all terminals Saturday through Monday.
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.MARINE...
Through Tonight: No marine concerns in the near-term as surface high pressure will be moving further out into the Atlantic tonight, shifting the winds from southerly to southwesterly. Winds are expected to remain below 10 knots.
Friday through Tuesday: A strong cold front will shift across local waters Friday night, leading to a sharp wind shift and deteriorating marine conditions across all local waters Saturday. Strong cold air advection associated with building high pressure in wake of the front will likely support northerly winds in excess of 25 kt and seas building to 5-8 ft later Saturday, supporting a period of at least Small Craft Advisory level conditions for all waters prior to further deterioration across marine areas. Gale force winds enter across local waters by Saturday night as cold air advection persists and a pinching of the pressure gradient occurs, resulting in enhanced north-northeast winds. Gale Watches/Warnings will likely be needed for all nearshore and offshore SC/GA waters Saturday evening through Monday, before improving conditions begin on Tuesday, although still likely supporting Small Craft Advisory level conditions into the middle of next week. There still remains some concern of reaching storm force wind gusts across parts of outer waters (NBM supports ~40% probability of 48 kt wind gusts), especially offshore Georgia waters during the peak of the event Sunday/Sunday night. This will continue to be monitored for a potential Storm Watch.
Strong north/northeast winds will also support large seas this weekend, potentially upwards to 7-11 ft across nearshore waters (largest in GA waters) and 10-15 ft across offshore waters (largest in GA waters). Elevated seas and strong/persistent north-northeast winds likely support breakers in excess of 5 ft along the beaches, largest across GA. High Surf Advisories are likely Sunday into Monday, and possibly along the GA coast into Tuesday. Thereafter, high pressure slowly modifies with a relaxing pressure gradient, leading to subsiding seas. However, long-period swell may persist after local winds decline, supporting elevated seas into the middle of next week. Mariners should continue monitor the forecast for this weekend before heading offshore.
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.CLIMATE...
Record High Temperatures:
October 15: KCHS: 87/2021 KCXM: 88/1925 KSAV: 90/1925
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA... None. SC... None. MARINE... None.
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APT/DPB