490 FXUS62 KCHS 060914 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 514 AM EDT Tue Apr 6 2021 .SYNOPSIS... High pressure will prevail through Wednesday night. A slow moving cold front will approach the area Thursday. The front will stall to our far west near the tail end of the week, eventually advancing across the region this weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 510 AM: Based on latest guidance, I will updated the forecast to lower afternoon dewpoints. This adjustment will bring afternoon RH close to 20 percent during the heat of the afternoon. As of 325 AM: Warm and very dry conditions will remain across the forecast area today. Near term guidance indicates that axis of a H5 ridge will remain just west of the forecast area today and tonight. At the sfc, high pressure is expected to remain centered over the western Atlantic off the FL coast, with ridging west across the I-10 corridor. The sfc pattern should yield a steady SW winds across the CWA today and tonight. Given deep subsidence and nearly full insolation, high temperatures are forecast to range in the low to mid 80s. Mixing is expected to extend to around 8 kft this afternoon, resulting in dewpoint to mix down into the upper 30s. Dry, clear, and light winds will remain tonight, supporting low temperatures in the low 50s inland to the mid to upper 50s along the coast. && .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... Wednesday: At the surface, the main center of broad high pressure will gradually shift offshore Wednesday while an upper closed low over the Central Plains shifts eastward. This will push the center of a ridge axis aloft over the Southeast US, maintaining influence of subsidence and drier air noted by model soundings. Another mild day with mostly sunny skies is forecast. Highs will near the mid 80s with coastal locations a few degrees cooler during the day due to the influence of cooler ocean waters and sea breeze effects. Low temps should range from the mid to upper 50s. Thursday: High pressure over the Atlantic will persist as a deep upper low over the Central Plains shifts to the northeast. Models continue to slow its movement due to highly meridional flow limiting its eastward propagation. A cold front extending from its associated surface low will approach from the west northwest. The surface low looks to occlude causing the cold front to stall along the windward side of the Appalachians. Moisture will increase ahead of the front as mid-level flow shifts out of the southwest. This will increase cloud coverage throughout the day, turning partly sunny skies to mostly cloudy by night. The forecast remains rain-free at this time. Highs will reach the low to mid 80s; a few degrees cooler than Wednesday. Temps along the immediate coast will be much cooler due to marine influences, topping out in the mid 70s. Friday: With a stalled front to our far west, rippling shortwave activity and upper divergence will allow showers and thunderstorms to develop throughout the day. The greatest forcing looks to exist over our extreme inland counties where low-end likely POPs have been introduced. Between cloudy skies and evaporative cooling, high temps will be slightly cooler; upper 70s to near 80F and cooler along the immediate coast. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... A second upper low looks to drop southward from the Canadian Rockies, cyclonically rounding the base of the stagnant low over the northern Midwest US. A potent shortwave rounding the base of its trough allows the stalled front to our west to advance eastward as high pressure over the Central Plains builds simultaneously. This weak cold front will drop in from the northwest and push across the region over the weekend. Surface forcing ahead of the front will promote the development of isolated showers/thunderstorms over the weekend. Thereafter, high pressure will build in the wake of the front and clearing skies are expected early next week. && .AVIATION /09Z TUESDAY THROUGH SATURDAY/... VFR. Extended Aviation Outlook: VFR. Flight restrictions are possible in showers/thunderstorms Friday into Saturday. && .MARINE... Today and tonight: Sfc high pressure will persist across the region through the near term period. WSW winds should favor speeds between 10-15 kts across the marine zones. Seas are forecast to range between 1-2 ft. Wednesday through Sunday: High pressure will remain the dominant feature over the waters through the end of the week. Southwest winds early in the week are expected to be less than 15 kt. Each day winds will shift southerly during the afternoon hours with respect to the sea breeze, returning southwesterly overnight. Seas will range 1-3 ft across all waters through Friday. A bit of a surge is expected over the weekend as a weak cold front approaches from the northwest. Southwesterly winds will increase slightly; generally 15 kt with gusts to 20 kt. Occasional gusts could near 25 kt, but should stay below Small Craft Advisory criteria. Seas will build to 2-4 ft with some 5 footers in the outer GA waters. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...NED SHORT TERM...BRM LONG TERM...BRM AVIATION...NED/BRM MARINE...NED/BRM