987 FXUS62 KCHS 160820 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 420 AM EDT Sun Jun 16 2019 .SYNOPSIS... Atlantic high pressure will prevail into Tuesday. An inland surface trough will develop by mid week then persist over the Southeast into next weekend. && .NEAR TERM /THROUGH TONIGHT/... Early this morning: The return flow of moisture off the Atlantic and higher dew points than the past couple of days, will generate patchy stratocumulus and some ground fog. Temps will start the day considerably warmer than Friday and Saturday began. For today: Flat ridging will prevail aloft, while surface and low level high pressure extends from the Atlantic overhead, as a subtle lee side trough develops. There is still plenty of dry air in the H7-H3 layer, but with PWat climbing back closer to normal for mid June, the sea breeze may have something to work with to generate showers and t-storms. Since there is still a cap around H85-H7 and low level lapse rates aren't that impressive, we won't show anything more than 20% POP this afternoon, mainly across Georgia. Scattered to broken cumulus clouds will develop, leading to partly or mostly sunny skies throughout, and with H85 temps of 16-17C, max temps will warm into the upper 80s and lower 90s. Tonight: As the surface ridge axis positions itself south of the area and within a southerly low level flow, it'll be an even warmer night, with lows around 2-3F above climo. Marine-induced showers will make a run for the coast, but with still quite a bit of subsidence, we don't have any mention of rain over land. There could be some fog overnight with favorable condensation pressure deficits and the lack of mixing. But since it'll be a little tough to reach our cross-over temps, we have not included it in the forecast at this time. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... Monday: Most of the day will still be under broad upper ridging although gradually deepening moisture will advect north across South GA. Temps should warm into the lower 90s inland during the afternoon with isolated to scattered showers and tstms developing as the sea breezes pushes inland. We have POPs tapered from 20 percent Charleston area to 30-40 POPs inland GA where the higher 850 MB theta-e advection is noted after 18Z. Tuesday: The upper ridge will give way to a dampening mid level short wave which is forecast to move from the Tennessee Valley region early in the day into GA and the Carolinas Tuesday night. Over our area during the convection initiation hours of the afternoon, no real stand-out parameters or lifting mechanisms other than the typical sea breeze and mesoscale boundary are noted. We maintained chance POPs mostly in the 40 percent range inland from the coast. Another warm day on tap with temps once again lower 90s many areas. Wednesday: Deep layered wind fields will increase as the Piedmont surface trough develops inland. Conditions appear to favor convection by afternoon and showers and tstms should translate toward the coast but it is uncertain where any organization is possible given model discrepancies at this point. If upstream tstms develop, they could produce some severe weather as higher DCAPE values are indicated across the CSRA/Midlands. We will need more evidence before raising concerns for stronger storms. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... A fairly robust mid level short wave is progged to pass through the southeast states Thursday into early Friday. This appears to be the most significant period for a potential risk of organized convection as 700 MB flow increases greater than 30 kt over much of the area. Timing and convective mode look tricky and global models continue to show moderate to strong instability at times late week. It still remains quite uncertain how convection will play out at this juncture. On Friday, the surface trough will mostly move offshore and POPs range from slight chance northern SC zones to chance GA. Upper ridging is expected to build over the weekend with hot and humid weather and at least a slight chance for afternoon/evening showers and tstms. Temps on average will run above climo by several degrees for highs and lows through most of the medium range. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... Due to the higher dew points there could be a little ground fog at KCHS and/or KSAV close to daybreak. Then for later today, isolated SHRA and/or TSRA will form on the sea breeze, but any direct impacts at either airfield are too minimal to address at this time. Extended Aviation Outlook: Mainly VFR. Brief flight restrictions are possible in afternoon showers/thunderstorms, especially by mid week. && .MARINE... Today: The Atlantic Ridge will be the dominate weather feature as it stretches across the local waters. Sea breeze circulations will back our S and SW winds of 5-10 kt this morning around to the SE and S as high as about 10 kt this afternoon. Seas will be no larger than 2 or 3 ft all day. Tonight: The synoptic pattern holds under the influence of Atlantic high pressure, producing S winds around 10 kt throughout, with seas to hold in a fairly steady state at 2 or 3 ft. Monday through Friday: Between high pressure centered offshore and a trough of low pressure developing inland, winds will veer to south/southwest and increase in speed during the upcoming week. Winds of 15-20 knots will become more common by mid week, especially with the afternoon sea breeze near the coast and during periods of nocturnal surging, and gusts to 25 knots cannot be ruled out, especially overnight around midweek. Seas of 1 to 3 ft through Tuesday will build to 3-5 ft mid to late week. && .TIDES/COASTAL FLOODING... With the upcoming full moon and onshore winds, minor coastal flooding is possible along parts of the southeast South Carolina coast (mainly for downtown Charleston) with the high tide this evening. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE... TIDES/COASTAL FLOODING...