Marine Weather and Tide Forecast for Bamberg, SC

KEY MESSAGES
- 1. Heat Advisory in effect until 8 PM with heat indices up to 108F possible.

- 2. Severe thunderstorms and damaging winds are possible late this afternoon into the evening hours. Drier conditions then move in for the late week before rain chances increase again this weekend.

DISCUSSION
- 1. Heat Advisory in effect until 8 PM with heat indices up to 108F possible.

Temperatures are approaching the low 90s early this afternoon and should top out in the mid 90s in the coming hours, though some spots in the upper 90s will be possible. Dewpoints remain in the low to mid 70s and may fluctuate a bit as mixing deepens, but should settle between 69-72F for most spots as moist southwesterly flow continues and mean mixing ratios in the lowest 100mb continue to increase toward 16g/kg. Heat indices already range from 100-105F, and could top out around 108F in spots over the coming hours, depending on how much more surface dew points mix out. The Heat Advisory was expanded to include Lincoln, McCormick, and Edgefield Counties earlier this morning, but it also remains in effect along and south of I-20 until 8pm this evening. Depending on trends in timing for convection, portions of the advisory may be allowed to expire a bit earlier.

- 2. Severe thunderstorms and damaging winds are possible late this afternoon into the evening hours. Drier conditions then move in for the late week before rain chances increase again this weekend.

Latest obs/mesoanalysis: WV imagery reveals the mid level shortwave now dropping into portions of eastern KY, southern WV, and far NW VA, bringing with it a belt of enhanced 40-50 kt 500mb flow. A few early storms popped up in northern NC/southern VA, but these have largely outpaced upper support and have diminished. Surface analysis reveals the cold front is now shifting into northern KY, with new convection spawning ahead of it. The previously discussed enhanced kinematics are seen in regional VAD profiles as well where the latest 17z VAD from Roanoke VA displayed elongated hodographs with near 45 kts of deep layer shear, but also nearly 25-30 kts of sfc- 1km shear.
Looking down south into our CWA, strong heating and surface dewpoints still in the low to mid 70s have lead to the development of robust SBCAPE values on the order of 2500-3000 J/kg, but as low level lapse rates have been steeping, a corridor of DCAPE values between 1000-1200 J/kg is seen across the northern FA. It is worth noting that as the strong shortwave continues shifting toward the Mid-Atlantic, effective shear values over the northern FA are already approaching 25-35 kts with the recent KCAE VAD profile starting to pick up on enhanced 35-45 kt mid level flow.

Remainder of the afternoon and evening: Little in way of convective coverage is expected through about 20-22z, as the FA remains south of the front and upper kinematics, but convection now blossoming in northeast KY (associated with the shortwave and front) will be the main focus. Latest radar trends would put this activity pushing in near the Pee Dee by 00-03z, but this is subject to change as the propagation speed may change as better organization occurs. The bigger question before the front nears in the aforementioned timeframe is if any discrete/semi- discrete cells form across portions of NC that could push into northern parts of the area. Majority of 12z guidance, including the mean HRRR solution would suggest this is not looking likely, which is reasonable considering increased debris cloudiness is currently seen over central NC with RAP mesoanalysis suggesting less instability due to this. Overall, observational and 12z guidance support convection working into the Pee Dee/northern Midlands this evening, bringing the main threat of damaging wind gusts and possibly some small hail. Confidence remains low in the southern extent of convection with little guidance indicating robust storms making it much further south than Richland County (even this may be a stretch). The front then works in overnight, with drier conditions expected.

Remainder of forecast period: Solid agreement remains in ensemble and model guidance that behind the front, much drier air works in Wednesday through Friday with PWAT's falling to nearly 2-3 standard deviations below normal. This should bring relief from the humidity and nice weather as temperatures remain near normal. Heading into the weekend, global models indicate another sharp shortwave rounding the robust ridge (which should have retrograded near the Four Corners region at this point).
Increased southwesterly flow should bring returning moisture and increased rain chances as this wave works into the region.

AVIATION /18Z TUESDAY THROUGH SUNDAY/
Brief morning fog/stratus possible.

Winds remain out of the southwest around 10 knots, with some gusts up to 18 knots through the afternoon ahead of an approaching front. Currently taf locations are vfr, and outside of any potential afternoon/evening convection, vfr should prevail. Regional radar showing a batch of showers and storms moving through western and central NC early this afternoon.
Guidance continues to track this activity southward ahead of the approaching cold front, but appears to keep it north of Midlands taf sites through 00z. There remains differences in the models in regards to both timing and overall coverage of any showers/storms as they progress through the area, so confidence remains on the lower side right now for aviation impacts. With that said, did include a mention of Prob30 with ifr/mvfr restrictions around most taf sites this evening and into the overnight hours, mainly around the most likely timing of any activity for now. Expect amendments later as activity gets closer if needed.

After the front moves through late tonight, winds will begin to turn westerly then northwesterly after sunrise on Wednesday, with speeds around 5 knots or so. Vfr will prevail Wednesday as drier air pushes into the region.

EXTENDED AVIATION OUTLOOK...Drier air moves in for the second half of the week. Next chance for rain and restrictions not expected until the weekend.

CAE WATCHES/WARNINGS/ADVISORIES
SC...Heat Advisory until 8 PM EDT this evening for SCZ016-018-022- 025-027>031-035-037-038-041-135>137.
GA...Heat Advisory until 8 PM EDT this evening for GAZ040-063>065- 077.