Marine Weather and Tide Forecast for Jacksonboro, SC

KEY MESSAGES
- 1) Periodic showers and thunderstorms expected to continue this week with a persistent summertime pattern.

- 2) Minor coastal flooding looking less likely along Charleston and Colleton County coast during upcoming evening high tides.

DISCUSSION
KEY MESSAGE 1: Showers and thunderstorms expected to continue into early next week with a persistent summertime pattern.

As broad upper level troughing continues aloft, a weak surface cold front will be approaching the region from the northwest throughout the day. The current weak upper level wave producing the broken line of showers as of 6Z is expected to continue to weaken and dissipate by sunrise, with overnight lows remaining in the mid to upper 70s.
This wave looks to shift majority of the elevated instability and mid-level moisture south of the SC/GA state-line, possibly as far south as southern Georgia. At the surface, the aforementioned cold front continues to move towards and eventually into the region this evening, before stalling near a line from Reidsville, GA to Moncks Corner, SC.

A group of scattered shortwaves moving through the base of the trough will likely produce another round of showers and thunderstorms this afternoon and evening, primarily for areas along/south of the I-16 corridor where there is up to 2000 J/kg of SBCAPE to work with. The lack of shear will continue to produce primarily pulse shower/storm activity, though cold-pool driven thunderstorms may produce isolated strong winds given 1000 J/kg of DCAPE. While PWATS remain near 2.0 inches, storms looks to remain progressive enough to limit locally heavy rainfall potential, unless repeated storms were to occur. As a result, HRRR probabilities for an inch of rain are only 30% along the SC/GA border, rising towards 70% along the GA/FL border.

Heading into the overnight period, additional shortwaves build further to the north expanding coverage of showers and storms into southeast South Carolina, further amplified by a weak surface low pressure that attempts to form along the stalled cold front into Tuesday morning. While we'll likely see breaks from the rain at times, continued shortwaves rounding the base of the trough will lead to scattered showers and thunderstorms on Tuesday. Given the cloud and rainfall coverage, Tuesday is looking to be much cooler.
Areas of interior GA may only get up into the lower 80s, rising towards the upper 80s along the SC and GA coastline. The aforementioned surface low pressure, or at the very least surface trough, will lead to an elevated surface pressure gradient, resulting in breezy southwesterly winds throughout the day.

While we'll likely see a break from the rain late Wednesday into Thursday as drier air sneaks into the mid-level flow, moisture is quick to return resulting in the pattern looking to remain active into the end of the week. Broad troughing will continue aloft, with another cold front moving towards the area by late week/early weekend. The pattern isn't overly supportive of severe weather or locally heavy rainfall until the cold front arrives, though the additional rainfall will continue to provide much needed relief from the ongoing drought conditions.

KEY MESSAGE 2: Minor coastal flooding possible along the Charleston and Colleton County coasts during the evening high tide Monday.

The recent lunar Perigee (June 14th) and upcoming New Moon (June 15th) will continue to lead to elevated astronomical tides, though the west-southwest surface winds are not overly conducive for high tidal departures, as has been the case the past couple evenings.
Latest TWL forecast calls for 6.8-7.0 ft MLLW Monday evening from a 6.66 ft MLLW astro tide, so it is looking unlikely that a Coastal Flood Advisory will be needed for the Charleston and Colleton county coastline, though that will be closely monitored. Another chance for coastal flooding Tuesday evening with an astro tide of 6.55 ft MLLW, though again southwesterly surface flow should keep us from reaching advisory criteria.

AVIATION /06Z MONDAY THROUGH FRIDAY/
6Z TAFs: VFR conditions expected for the overnight and morning period with southwesterly winds of 5-10 knots, with a few gusts into the upper teens along the coast. The lingering shower/storm activity looks to have produced some very isolated MVFR cigs, but confidence is not high enough to include at the TAF and is expected to remain short-lived. Afternoon scattered showers and thunderstorms are again expected today, primarily for southeast Georgia, possibly producing TEMPO flight restrictions at times. Latest guidance would indicate this activity will occur south of the KSAV terminal.

Extended Aviation Outlook: VFR conditions should prevail at CHS/JZI/SAV terminals through the weekend, although TEMPO flight restrictions are possible with afternoon showers/thunderstorms throughout the week. Chances for flight restrictions remain moderate into the middle of the week with shower/thunderstorm coverage expanding locally ahead of an arriving cold front.

MARINE
A moderate SW gradient will persist over the waters this week as Atlantic high pressure remains in place and a surface trough sits inland. We could see wind gusts approach 25 kt over the SC nearshore waters Wed and Thu afternoons. Small Craft Advisories may be needed Friday as the gradient tightens a bit with the approach of a cold front.

CLIMATE
Record High Temperatures:

June 15 KCHS: 98/2015

Record High Minimum Temperatures:

June 15 KCHS: 80/2010

June 16: KCHS: 78/1998

June 18 KCHS: 78/2015

June 19 KCHS: 79/2025 KCXM: 81/2025 KSAV: 79/1881

CHS WATCHES/WARNINGS/ADVISORIES
GA...None.
SC...None.
MARINE...None.