Marine Weather and Tide Forecast for North Charleston, SC

KEY MESSAGES
- 1) Rain chances return Wednesday and again late week into the weekend.

DISCUSSION
KEY MESSAGE 1: Rain chances return Wednesday and again late week into the weekend.

Aloft, h5 shortwave energy associated with a broad mid-lvl trough will ripple across the Southeast United States Wednesday, while a sfc cold front advances across the local area with scattered to numerous light/moderate showers starting around daybreak (30-50% chance), then expanding east and peaking in coverage early afternoon (60-80% - highest across Southeast South Carolina), before ending from west to east during evening hours. Precip amounts remain on the lighter side despite a fairly large swath of moisture (PWATs near 1.25 inches) and the duration/speed of the front, although a thunderstorm or two can not be ruled out across Southeast Georgia mid-late afternoon.
Most areas could see rainfall accumulations in the 0.1 to 0.25 inch range. NBM probabilities for 24-hr rainfall amounts ending 7 AM Thursday indicate 40-70% for amounts >0.10" and 20-40% for amounts >0.25" with highest values along the immediate SC coast.
Any precip is anticipated to end by midnight Thursday.

Attention turns to a more substantial rainfall event this weekend with models indicating a potent mid-lvl low passing across the Southeast during a time when the local area becomes warm-sectored Saturday into Sunday. Latest model trends suggest the peak of precip coverage occurring Sunday afternoon/evening (70-90% chance) when moisture supply is largest (PWATs 1.25-1.50 inches) during peak forcing. Despite some variability in the strength and track of the low, ensemble guidance displays a 70-80% chance for QPF amounts >0.5" and 50-70% for >1.0". QPF amounts around an inch continue to be advertised by WPC late weekend as well, which appears reasonable given some locations should experience thunderstorm activity within warm- sectoring/southerly flow prior to the low pressure system/front shifting offshore late Sunday/early Monday.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
11/00z TAF Discussion: KCHS/KJZI/KSAV: VFR through 12/00z. Light rain will spread into the area from the west by daybreak. Do not anticipate any meaningful reductions in vsbys given the fairly dry sub-cloud layer (8000-10,000 ft). A cold front will approach KCHS/KJZI right at the end of the 00z TAF period and may be accompanied by a band of heavier showers. No mention was included at this time given it would be in the 22-00z time frame, but the risk for at least MVFR vsbys could occur with that line.

Extended Aviation Outlook: Flight restrictions are possible this weekend as a system tracks across the region.

MARINE
Through Tonight: Southwesterly winds will strengthen as the local waters become sandwiched between a high pressure located across the southwestern Atlantic and a low pressure sitting over the Great Lakes region. This set-up will yield wind speeds of 10 to 15 kts across the majority of the marine zones with 15 to 20 kts with gusts up to 25 kts possible across the nearshore Charleston and outer Georgia waters. A bit of east-northeasterly swell surges into the local waters with waves 2 to 4 ft in the nearshore waters and 3 to 6 ft in the outer Georgia waters.
Hence, a Small Craft Advisory has been issued for the nearshore Charleston and Georgia offshore waters for late tonight through Wed. afternoon.

Wednesday through Saturday: East-southeasterly winds will prevail through Wednesday afternoon as conditions slowly improve across the Atlantic waters due to the pressure gradient relaxing back. As the front passes through on Wednesday afternoon, winds will veer out of the northeast through the remainder of the period. Expect winds to dial back and remain relatively calm after Wednesday as east- northeasterly swell lingers. However, conditions look to remain under Small Craft Advisory thresholds.

CHS WATCHES/WARNINGS/ADVISORIES
GA...None.
SC...None.
MARINE...Small Craft Advisory from 1 AM to 3 PM EST Wednesday for AMZ350-374.