106 FXUS62 KCHS 230603 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 203 AM EDT Sat May 23 2020 .SYNOPSIS... A stalled front will remain over or near the area this weekend. High pressure will then build to the north early next week and persist for much of the week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... As of 2 AM: Radar trends indicate that the leading edge of showers and thunderstorms will push east and north of the forecast area over the next hour. Stratiform rain will likely persist for several more hours. I will update the forecast to adjust PoP placement and timing. Previous Discussion: Late this evening: As mentioned previously, the next area of concern was southeast Georgia and it has not disappointed in the last couple of hours. The westward moving sea breeze collided with outflow from convection across central and south-central Georgia and a strong line of storms rapidly developed from around Long County north to Jenkins and Screven counties. With the initial interaction with the sea breeze, thunderstorms seemed to get a boost and became severe for a short time. Now radar imagery shows that outflow is starting to out run the ongoing line and the embedded updrafts are much more tame. The question now is how far east will this activity make it before dissipating and running out of instability. Updated rain chances to increase into the 80-90 percent range for much of southeast Georgia and the South Carolina side of the Savannah River. This line should run out of steam the further east as it moves into more stable air. && .SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/... A closed mid/upper lvl low will shift off the Northeast coast Saturday, allowing a mid/upper lvl ridge of high pressure to expand across the Southeast United States late weekend and heading into early next week. At the sfc, a weak/stationary front will linger near the area Saturday and Sunday, before shifting south as high pressure gradually builds into the area from the north late Sunday into Monday. Although forcing is somewhat weaker during this period, ample moisture (PWATS between 1.5-2.0 inches) along with strong diabatic heating will support modest instability and the potential for few to scattered showers/thunderstorms each day, but the greatest coverage should occur Sunday afternoon through Monday near the front. High temps should range in the lower 90s for most locations away from the coast Saturday and Sunday, then range in the mid/upper 80s Monday. Overnight lows should be mild, dipping into the upper 60s/lower 70s away from the immediate coast. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Moderate confidence this period. High pressure should persist to the north of the area with an onshore wind prevailing. Some higher bands of moisture and upper forcing look to affect the area from time to time keeping at least a small chance of rain around pretty much at any point but there does not appear to be a significant heavy rain/severe weather threat at this time. Temperatures should be near to slightly above normal. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... Prior to the 6Z TAFs, KCLX detected a few thunderstorms departing the KCHS terminal with stratiform rain across KSAV. The rainfall at both KCHS and KSAV is expected to end between 7-8Z. The rest of the night should feature BKN to OVC mid to high debris clouds. Dewpoints depressions will remain very narrow through sunrise Sat, however, given the sky conditions I will leave fog out of the forecast at this time. The environment is expected to recover through the morning hours. Scattered to isolated showers and thunderstorms ahead of a late afternoon sea breeze. At this time, the greatest coverage appears inland of the terminals, TAFs will not highlight the convection. Extended Aviation Outlook: Brief flight restrictions are possible Saturday through Monday due to showers/thunderstorms. Otherwise, VFR conditions are expected to prevail. && .MARINE... Tonight: A weak pressure gradient will lead to S winds 10-15 kt, veering to the SW this evening. Swells with periods ~11 seconds resulting from the remnants of Arthur will persist. Seas will be in the 3-4 ft range within 20 nm and 4-5 ft for the GA waters beyond 20 nm. Saturday through Wednesday: A stationary front will remain draped near the area this weekend before high pressure builds across the area Monday and persists through the middle of next week. Marine conditions will remain well below Small Craft Advisory levels during the weekend and heading into early next week. In general, southerly flow will remain at or below 10-15 kt this weekend, then should increase and turn more east- northeast around 15 kts Monday through Wednesday. Seas will slowly build up to 3-5 ft next week with the onshore flow in place, but conditions are still expected to remain below Small Craft Advisory levels heading into the middle of next week. Rip Currents: Lingering swells from the remnants of Arthur combined with onshore winds will continue to generate a Moderate Risk of rip currents for the entire coast through Saturday. The risk should then lower along the beaches Sunday due to the subsiding swell. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...NED SHORT TERM...DPB LONG TERM...RJB AVIATION...NED MARINE...DPB/MS