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.

Overall, warm and dry conditions will prevail through Friday. Ridging aloft will steadily slip eastward and off the coast by Friday morning as a sharp trough shifts through the Upper Midwest and the Great Lakes region. At the surface, weak high pressure will sit across the area today moving off the coast Friday as a strong cold front approaches from the northwest late in the day. We will again be near daily records today (see Climate section) followed by more mid to upper 80s for Friday.

Patchy shallow ground fog is expected again this morning. While widespread significant visibility reduction is not expected, there could be a few patches that produce sharp visibility changes over short distances.

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

Friday: High pressure will gradually shift offshore on Friday as a strong cold front approaches from the northwest. This will yield warm conditions ahead of the boundary, with afternoon highs in the mid to high 80s. Southwesterly winds are expected to increase somewhat during the day as the pressure gradient tightens ahead of the front. The latest model guidance generally favors a relatively dry frontal passage with a few sprinkles late Friday night into Saturday morning mainly across portions of northern Dorchester and Berkeley Counties. The front is forecast to cross the region overnight, with cooler and drier air filtering into the area from the north.

Saturday: A noticeably cooler airmass should be present across the region on Saturday in wake of the cold front. High temperatures will struggle to reach around 70 degrees across much of the region, representing a substantial change from the warmth experienced during the work week. Expect north- northeasterly winds to become quite breezy with speeds 15-20 mph and gusts up to 25 mph. The combination of cooler temperatures and persistent winds will make conditions feel distinctly more like fall. Saturday night will turn chilly as high pressure continues to build southward across the Carolinas and into Georgia.

Sunday: Expect cool and breezy conditions to continue as high pressure continues to expand into the Eastern CONUS. Afternoon temperatures will range from low to mid 60s across much of the region with upper 60s along the coastline. Overnight lows may fall into the upper 40s across inland locations, with readings in the 50s closer to the coastline. The combination of low humidity, rain-free forecast, and periods of sunshine should produce crisp, seasonable fall-like weather.

The center of surface high pressure should shift offshore of 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 /06Z THURSDAY THROUGH MONDAY/

VFR conditions are expected to prevail at KCHS, KJZI, and KSAV through 06z Friday. We will likely again see shallow ground fog right around sunrise this morning. We currently do not anticipate any significant visibility reductions and have kept the forecast VFR. However, there is a low chance for a brief period of sub-VFR conditions. Extended Aviation Outlook: VFR.

MARINE

Today through Friday: Conditions will remain quiet across the local waters today with winds topping out around 10 knots this afternoon and evening. By Friday, winds will turn to become more southwesterly ahead of an approaching cold front. Winds are expected to top out in the 10-15 knot range for most of the day, increasing into the 15-20 knot range late. Seas are expected to average around 2 feet through Friday.

Friday through Monday: As a strong cold front passes across the local waters late Friday night into Saturday morning, this will yield to a sharp wind shift and deteriorating marine conditions. Winds will shift to the north and strengthen, with sustained winds preaching 25-30 kts with gusts up to 35-45 kts possible through Sunday night. This will likely warrant Gale Warnings for all of the local waters + a Small Craft Advisory for the Charleston Harbor on Friday night through early Monday morning. It's important to note that some guidance has trended much stronger for the marine wind gusts on Sunday into Sunday evening, with the NBM continuing to indicate the change for storm force (48 kts) wind gusts across the outer Georgia waters and portions of the offshore South Carolina waters. It's possible that a Storm Watch/Warning might be warranted for that portion of the waters Saturday night into Sunday night.

Seas will build to 7 to 10 ft, with 10 to 15 ft possible farther offshore (highest across the outer Georgia waters). The elevated seas will likely result in breakers in excess of 5 ft, with High Surf conditions this weekend, especially along the GA coast. Thereafter, the post-frontal airmass will continue to modify with winds gradually easing backwards and turning more easterly on Monday. However, a longer-period swell may persist after the local winds diminish with elevated seas forecast to last into the mid-week. Mariners should continue monitor the forecast for this weekend before heading offshore.

CLIMATE

Record High Temperatures:

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.