textproduct: Charleston

WHAT HAS CHANGED

A short duration Small Craft Advisory is now in effect for the Charleston Harbor through 10 AM as well as a Lake Wind Advisory for Lake Moultrie. The Aviation Section has been updated for the 12z TAFs.

KEY MESSAGES

- 1) High pressure will build into the SC Lowcountry and SE GA from the north today and remain through mid-week. This set-up will yield dry and cooler conditions, along with an elevated fire risk.

DISCUSSION

KEY MESSAGE 1: High pressure will build into the SC Lowcountry and SE GA from the north today and remain through mid-week. This set- up will yield dry and cooler conditions, along with an elevated fire risk.

A wedge of high pressure will set up along the eastern side of the Appalachian Mountains today, resulting in a cold air damming (CAD) regime across the local area. Cooler temperatures are expected today, with highs only reaching into the upper 60s to around 70. With the building high pressure, wind gusts out of the northeast will be around 20 mph through most of the day, diminishing in the evening. Strong mixing will occur due to the gusty NE winds, allowing dew points to drop into the mid 30s far inland. These values will yield RH values 25-30% across areas west of I-95.

A brief respite from building high pressure will occur Monday night, with another CAD regime setting up Tuesday into Wednesday. This high pressure is forecast to be stronger than the initial high pressure on Monday. Northeast gusts Tuesday and Wednesday afternoons are forecast to reach 20-25 mph on Tuesday, with gusts to 30 mph possible on Wednesday. RH values are forecast to be 25-30% west of I- 95. These conditions are hazardous for fire weather and a Fire Danger Statement or even a Fire Weather Watch/Red Flag Warning may be required for portions of the forecast area both Tuesday and Wednesday.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Prevailing VFR through the 12Z TAF period at KCHS/KJZI/KSAV. Gusty northeasterly winds will develop around sunrise, gusting to around 20-25 knots at all terminals. Gusts will diminish around sunset.

Extended Aviation Outlook: VFR, with breezy NE winds Wednesday and Thursday.

MARINE

Today: A surge in winds is expected to develop into the morning hours as a surface high pressure dives down towards the Gulf Coast, creating sustained winds in the 20-25 knot range out of the northeast with gusts to 30 knots. Waves will rise to the 3-4 ft range along the coast to 7+ ft in the offshore Georgia waters, with winds briefly subsiding this evening.

Tuesday through Friday: As a stronger surface high pressure moves across the Great Lakes region Tuesday, the surface pressure gradient again tightens leading to sustained winds in the 20-25 knot range with gusts to 30 into the morning hours on Tuesday. A high pressure wedge sets up along the northeast coast on Wednesday, and will lead to an increasingly pinched gradient where A Gale Watch has been issued for all waters off the coast, and a Small Craft Advisory issued for the Charleston Harbor. Wave heights on Wednesday just offshore look to be in the 7 to 8 ft range, possibly exceeding 15 feet in the offshore Georgia zone 60nm off the coast. Gale conditions subside overnight into Thursday, though breezy NE winds continue into Friday before decreasing below Small Craft Criteria threshold with unsettled seas lingering into early Saturday.

Rip Currents: Increase NE winds and building swells will result in a moderate risk for rip currents along all areas beaches today and Tuesday. The rip current risk will remain elevated for the rest of the upcoming week.

High Surf: High surf and beach erosion could impact the beaches Wednesday through Friday as seas build 8+ feet over the coastal waters. High Surf Advisories may be needed.

CHS WATCHES/WARNINGS/ADVISORIES

GA...None. SC...Lake Wind Advisory until 10 AM EDT this morning for SCZ045. MARINE...Small Craft Advisory until 10 AM EDT this morning for AMZ330. Small Craft Advisory until 2 AM EDT Wednesday for AMZ350-352. Gale Watch from late Tuesday night through late Wednesday night for AMZ350-352-354-374. Small Craft Advisory until 2 AM EDT Wednesday for AMZ354-374.