textproduct: Charleston

WHAT HAS CHANGED

The Aviation section was updated for the 00z TAF issuance.

KEY MESSAGES

- 1) A multi-day coastal flooding event will slowly diminish through the remainder of this week. - 2) Sustained northeast winds will lead to a High Risk for rip currents along our South Carolina and Georgia beaches through Thursday. - 3) Dry and warming conditions will continue through the week before rain chances increase late weekend.

DISCUSSION

KEY MESSAGE 1: A multi-day coastal flooding event will slowly diminish through the remainder of this week.

The full moon was on 10/26, while the lunar perigee occurs today. Therefore, astronomical tides will be trending lower the rest of this week with the morning/early afternoon high tide being the higher of the two tide cycles. Additionally, northeasterly winds are expected to gradually ease, especially towards the end of this week. This will also cause tidal departures to lower.

Charleston Tide Gauge: Moderate coastal flooding is forecasted with the Thursday morning high tide cycles, followed by minor coastal flooding Friday, and Saturday. Coastal Flood Advisories will be needed.

Fort Pulaski Tide Gauge: We may briefly hit minor coastal flooding with the Thursday morning high tide. A Coastal Flood Advisory may be needed.

KEY MESSAGE 2: Sustained northeast winds will lead to a High Risk for rip currents along our South Carolina and Georgia beaches through Thursday.

Gusty northeast winds, elevated tides and persistent elevated seas will keep a high risk for rip currents in place for all beaches into Thursday. Winds will begin to back off for Friday, but lingering elevated tides and seas will push the rip current risk into the high range for the Georgia beaches with moderate for the beaches of the South Carolina Lowcountry. An elevated risk will linger into the weekend into early next week as winds and seas build in response to the formation of a coastal trough just offshore.

KEY MESSAGE 3: Dry and warming conditions will continue through the week before rain chances increase late weekend.

High pressure will begin to slowly breakdown by Friday as upper ridging aloft deamplifies. Conditions should remain dry through Friday night, although a few marine-based showers could impact the Georgia and far southern South Carolina coast Saturday as a weak coastal trough forms just offshore. Temperatures will steadily warm into the weekend, with highs pushing 80 away from the coastline by Friday. Overnight lows initially in the 50s will warm into the 60s.

A rather drastic shift in the synoptic pattern is expected this Sunday and Monday as a southern stream shortwave pivots across the Deep South and Southeast States. There remains much uncertainty on how strong this trough and any corresponding surface reflection will be. This uncertainty is best reflected in the LREF QPF fields which show large 6-hour interquartile ranges during this time. While the specifics are yet to be determined (degree of forcing aloft, amount available instability, etc), it does appear conditions will become increasingly unsettled this weekend into early next week with higher rain chances. High pressure will reestablish itself Tuesday into Wednesday, although rain chances could begin to increase late Wednesday afternoon into Wednesday night as both moisture and lift begin increase ahead of a cold front approaching from the west.

AVIATION /00Z THURSDAY THROUGH MONDAY/

The 00z TAF period begins with VFR conditions at KCHS, KJZI, and KSAV. The only forecast issue concerns the potential for morning ceilings to impact the terminals again. Overall, the setup is the same as it was for this morning. Model guidance is mixed and not particularly aggressive with lowering ceilings too much. Favoring a bit of a persistence forecast, we have maintained a period of MVFR ceilings at all 3 TAF sites starting around or just after sunrise and continuing through about mid morning. Otherwise, northeast winds will remain elevated and could produce some gusts into the 15-20 knot range in Thursday afternoon.

Extended Aviation Outlook: Gusty northeast winds are possible Saturday into Monday.

MARINE

Tonight: High pressure will persist inland, maintaining elevated northeast winds and seas. Small Craft Advisories remain in effect for all of the waters out to 20 nm (excluding the Charleston Harbor) and for the GA waters from 20-60 nm. The highest waves will continue to be further offshore.

Thursday through Sunday: Elevated northeast winds and seas will keep conditions at or above Small Craft Advisory conditions into Friday. Seas may drop below 6 ft across the nearshore waters briefly for Friday, but this should be short lived. Both winds and seas will increase again over all nearshore and offshore waters Saturday into Monday as the gradient tightens a bit with the development of a coastal trough just off the coast. Winds are typically highest over the nearshore waters in these scenarios where the pressure gradient tends to tighten the most and this matches the 28/13z NBM rather well. Expect northeast winds of 20-25 kt with gusts to 30 kt to prevail Saturday and continuing into Monday. Seas will build 4-6 ft Saturday with 5-7 ft Sunday into Monday. Winds in the Charleston Harbor looks to peak just shy of advisory thresholds, but it could be close at times, especially near the harbor entrance.

CHS WATCHES/WARNINGS/ADVISORIES

GA...High Risk for Rip Currents through Thursday evening for GAZ217-219- 239-241. SC...High Risk for Rip Currents through Thursday evening for SCZ148>151. MARINE...Small Craft Advisory until 8 AM EDT Friday for AMZ360-362. Small Craft Advisory until 2 PM EDT Friday for AMZ364. Small Craft Advisory until 6 AM EDT Tuesday for AMZ384.