Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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540 FXUS62 KCHS 020606 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 206 AM EDT Tue Jul 2 2024 .SYNOPSIS... A cold front will impact the area tonight into early Tuesday before dissipating offshore. A hot and humid air mass will build over the region during the latter half of the week. By Monday, a weak cold front may reach coastal Georgia and South Carolina. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... Tonight: Sfc analysis continues to show a front currently draped east to west across the local area, from the South Carolina coastal waters through the Beaufort, SC area and inland just south of the Metter, GA. The environment remains very moist along and south of the feature (PWATs around 2.2 inches), suggesting showers and thunderstorms continuing for a few more hours near the front where moisture convergence is enhanced. Moderate to isolated heavy rainfall is possible, especially near the coast where an onshore flow continues to advect ample moisture over land near the front. Here an additional 1-3 inches of rainfall is possible tonight. Latest radar trends are also suggesting some development of showers and thunderstorms along the southeast Georgia coast, shifting north within a light southerly flow and potentially impacting the Savannah Metro given the front will be slow to make further southward progress overnight. Overnight lows will be slightly cooler than the previous night, particularly north of the front. In general, low temps should range between the upper 60s/lower 70s well inland and north to mid 70s across southeast Georgia. Temps should remain in the upper 70s near the Georgia beaches. && .SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY/... Tuesday: The surface pattern is expected to feature a stalled boundary across SE GA with drier high pressure ridging across the SC Lowcountry. The environment along and south of the front should continue to feature deep instability and PW. The forecast will feature scattered to numerous showers and thunderstorms along and south of the front, keeping portions of inland SC dry. Using a blend of MOS, high temperatures are forecast to range in the mid to upper 80s. Wednesday: Short term guidance indicates that a 595 dm ridge will build over the Deep South and Southeast CONUS. At the sfc, the center of high pressure will remain off the NE and middle Atlantic states, resulting in ENE flow across the forecast area. This pattern will support a sea breeze to develop, serving as a focus for deep convection. Given the wide field of instability, scattered to numerous showers and thunderstorms are forecast to develop along the sea breeze. High temperatures are forecast to range around 90 degrees. A few counties across extreme SE GA may see heat index values peak between 100-105 degrees. Independence Day: Mid-level ridge will build over the forecast area on Thursday. Given high pressure over the western Atlantic, a sea breeze may develop during the afternoon. However, GFS forecast soundings indicate drier conditions compared to the first half of the week. Forecast soundings indicate PW around 1.5 inches with an inversion centered at H65. This profile indicates limited instability. The forecast will indicated isolated showers and thunderstorms. High temperatures are forecast to range between 90-95 degrees over dewpoints in the low to mid 70s. Heat index values are forecast to peak between 100-105 degrees. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... Friday through Sunday, the feature of concern will remain the 595 dm ridge over the region. The forecast area under the strong ridge will feature high temperatures in the mid to upper 90s each day. In addition, dewpoints will climb in the mid to upper 70s. The max heat index will range between 105 to 113 each afternoon. This may result in either a Heat Advisory or a Excessive Heat Warning late this week into early next week. The forecast will indicate diurnal isolated to scattered showers and thunderstorms each day. On Monday, a weak front will approach from the west as the mid- level ridge shifts over the western Atlantic. Conditions across the forecast area will remain hot. However, storm coverage should increase, bringing some relief from the heat. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... KCHS/KJZI: MVFR cigs will prevail through 10Z Tuesday, before turning to VFR late morning. However, recent shower development along the southeast South Carolina coast could drift back over the terminals tonight, leading to reduced vsbys, and perhaps IFR conditions before daybreak. For this reason, have started with TEMPO MVFR vsbys as well due to showers at the JZI terminal between 06Z-08Z Tuesday. KSAV: Light showers will continue to impact the terminal during the next hour or two. Regardless, MVFR cigs will prevail through at least 13Z, before gradually returning to VFR a few hours after daybreak. Additional showers and thunderstorms remain possible at the terminal Tuesday afternoon with a nearby front and ample moisture in place. TEMPO flight restrictions will likely be needed in future TAF issuances to account for activity directly impacting the terminal. Outside of precip, MVFR cigs look to return by around 02Z Wednesday and could prevail through the night. Extended Aviation Outlook: Brief flight restrictions are possible in showers and thunderstorms, mainly in the afternoon and evenings through the period. && .MARINE... Tonight: A cold front will work slowly south across local waters. Winds will shift to the northeast behind the front with speeds reaching 15-20 kt in the South Santee-Edisto Beach nearshore leg late. A few gusts could touch 25 kt, but the duration and coverage are to small to justify a Small Craft Advisory at this time. Otherwise, winds speeds will remain 15 kt or less. Widespread showers/tstms could reduce vsbys to 1 NM or less at times. A few strong convective wind gusts in excess of 35 kt could also occur. Seas will average 2-4 ft. Tuesday through Saturday: Gusty ENE winds should develop across the nearshore SC waters on Tuesday. The region will remain between building high pressure and the front stalled to the south. Gusts are forecast to remain around 20 kts with 3-4 ft seas. Conditions are forecast to remain below Small Craft Advisory criteria through the rest of the week. A weak pressure gradient should support winds 15 knots or less and seas averaging 2-3 ft. && .CLIMATE... Daily Rainfall Records for July 1: KCHS: 2.66 set in 1948 KCXM: 1.64 set in 1966 (*As of 8pm, 1.93 has fallen today*) KSAV: 2.76 set in 1871 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...DPB SHORT TERM...NED LONG TERM...NED AVIATION...DPB MARINE...DPB