textproduct: Charleston

WHAT HAS CHANGED

All sections have been updated.

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.

DISCUSSION

KEY MESSAGE 1: Above normal temperatures and dry conditions will prevail through Friday.

Warm and dry conditions continue through Friday as a ridge of high pressure slides from west to east across the southeast Region. At the surface, dry high pressure will be weakening before moving into the nearshore Atlantic waters on Thursday into Friday. With h925 temperatures peaking in the 20-22 deg C range both today and Thursday, which is in the mid to upper 90th percentile for the dates, near-record to record high temperatures will be possible on both days. Areas away from the coast will peak in the mid to upper 80s, with lower to mid 80s along the coast, with the individual records at our climate sites in the climate section at the bottom.

Similar to what we saw earlier this morning, patchy shallow ground fog will be possible Thursday morning. Maximum dew points today should surge into the lower to upper 60s, and with overnight lows similarly in the lower to upper 60s, cross over temperatures are expected to be reached. However, with high condensation pressure deficits, the fog should be patchy and shallow. Areas in the vicinity of Darien, GA have the highest probabilities for visibilities below 1 mile near 25%.

KEY MESSAGE 2: Expect gusty winds and temperatures well below normal this weekend behind a strong cold front.

A strong cold front will sweep across southeast Georgia and the SC Lowcountry late Friday night into Saturday morning. NAM12 shows a frontal wave move north along the coast Saturday morning, resulting in a band of light of rainfall across the forecast area, GFS and ECMWF along with the AI variants generally agrees that it should be a dry cold front, only sprinkles across northern Dorchester and Berkeley Counties areas early Saturday morning. GFS H85 temperatures over Lake Moultrie cools by 10 degrees between 0Z Sat to 0Z Sun. As a result, temperature will fall well below normal on Sat, with highs ranging around 70 degrees. In addition, north-northeast winds across the region will be breezy, with gusts around 25 mph. In fact, north winds across Lake Moultrie may strengthen early Saturday, gusting around 25 kts. A Lake Wind Advisory may be needed beginning early Saturday morning.

Saturday night into Sunday, the center of a 1035 mb high will settle over VA by daybreak Sunday. The sfc high will ridge SW across the Carolinas and Georgia on Sunday. Northeast winds will continue through the period, generally between 10-15 mph with gusts between 20 to 25 mph. The northeast winds will maintain cool llvl thicknesses across the forecast area. Using a blend of guidance, low temperatures on Sunday are forecast to range from the upper 40s inland to the mid to upper 50s along the coast. High temperatures are forecast to range from the mid to upper 60s across SE GA and the SC Lowcountry.

The center of sfc high pressure should shift over off the New England coast on Monday, resulting in winds to weaken and shift from the east-northeast. Temperatures across the CWA should warm near seasonable normals, mid to upper 70s. Gradual warming expected through mid-week.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

Clear skies with light and variable winds will continue into the overnight period. Chances for patchy and shallow ground fog return late overnight, with areas in the vicinity of Darien, GA having a 25% chance for visibilities to get below 1 mile. Elsewhere, the fog is expected to be transient and thin. Any fog will dissipate shortly after sunrise, with no aviation concerns for the rest of the day. Extended Aviation Outlook: VFR.

MARINE

Tonight through Thursday: High pressure will continue the benign marine conditions. Winds will become southerly this afternoon and southwesterly overnight, remaining below 10 knots or less.

Friday through Monday: A strong cold front will sweep across the region late Friday night into Saturday morning. After the front late Friday night, winds will veer from the north and strengthen to 25 to 30 kts across the Charleston Harbor with gale wind gusts across the nearshore and outer SC/GA waters. Gale Watches are likely for all marine zones outside the Charleston Harbor beginning Friday night. A Small Craft Advisory is likely for the Charleston Harbor, beginning late Friday night. Guidance has trended much stronger for marine wind gusts Sunday into Sunday evening, with the NBM indicating peak probabilities, 40 percent, of storm force (48 kts) wind gusts across the outer GA waters and portions of the outer SC waters. If guidance remains strong, it is possible that Storm Watches/Warnings could be required for portions of the outer GA/SC waters Saturday night into Sunday night. At this time, the coastal waters forecast will feature gusts around 45 kts across the outer GA waters Saturday evening and again Sunday evening. Surging gale wind gusts appears to linger through Monday night

With gale to potential storm-force wind gusts, wave heights are expected to build to 7 to 10 ft Saturday-Saturday night, gradually building to 10 to 16 ft by Sunday-Sunday night. The elevated seas may result in breakers in excess of 5 ft, with High Surf conditions this weekend, especially along the GA coast. Wave heights should gradually subside through early next week. However, six ft or greater seas may remain across the nearshore and outer waters through Tuesday.

CLIMATE

Record High Temperatures:

October 14: KCHS: 88/2024 KCXM: 86/2024 KSAV: 88/2024

October 15: KCHS: 87/2021 KCXM: 88/1925 KSAV: 90/1925

EQUIPMENT

The National Weather Service Charleston Doppler Radar (KCLX) is expected to be down for around two hours Thursday morning for maintenance.

CHS WATCHES/WARNINGS/ADVISORIES

GA...None. SC...None. MARINE...None.