Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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578 FXUS62 KCHS 211959 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 359 PM EDT Sat Sep 21 2024 .SYNOPSIS... High pressure will linger across the region through early next week. A weak cold front may approach from the west around the middle of next week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... A mid-level trough will continue to shift off of the East Coast while a ridge centered across Texas shifts further east across the Deep South and into the Southeast U.S. At the surface, High pressure will remain across the Southeast U.S. This synoptic pattern will bring our area dry conditions. The fair weather cumulus will dissipate this evening. Though, some high cirrus should float overhead tonight. Winds are expected to go calm overnight away from the immediate coast. All of this should lead to some decent cooling. Lows should range from the mid 60s inland to upper 60s/lower 70s near the beaches. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... Sunday, the center of a 590 DM ridge will remain centered over TX as a closed low pivots off the coast of New England. Short term guidance indicates that weak mid-level vort max is timed to track across the forecast area during the afternoon. Temperatures under the mid-level ridge will steadily warm through the mid-afternoon, expected to peak in the low 90s for most location. HREF indicates that sea breeze will develop during the mid to late afternoon, surging inland. The hot temperatures over dewpoints around 70 should result in CAPE values between 500-1000 J/kg along and ahead of the sea breeze. CAMs indicate that isolated showers may develop near the sea breeze, primarily over the SC Lowcountry. Monday and Tuesday, the axis of a H5 ridge will ripple across the forecast area. GFS forecast soundings indicate that a strong inversion is expected to remain centered around H55, likely keeping conditions capped. The forecast will feature dry and hot weather for Monday and Tuesday. High temperatures are forecast to range from the upper 80s to low 90s. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... Wednesday, the forecast area will remain under the influence of the H5 ridge centered over the western Atlantic. At the sfc, high pressure centered over the Mid-Atlantic States is expected to ridge south across the region. It is possible that a sea breeze could trigger isolated showers during the afternoon. However, the degree of instability remain too uncertain to added PoPs to the forecast. High temperatures should remain in the upper 80s to around 90. Thursday through the rest of the week, details of the forecast will largely depend on the intensity, placement, and timing of a potential tropical system sourced from the Gulf of Mexico. See latest NHC Tropical Weather Outlook for latest information. Based on the collaborated low position, the system is expected to remain to the west. The forecast will indicate generally scattered showers at this time. Given the thick cloud cover and anticipated rainfall, high temperatures are forecast to range between 80-85 degrees. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... 18z TAFs: VFR. Extended Aviation Outlook: VFR. && .MARINE... Tonight: The interaction between High pressure inland and a weak trough well south of our area will yield NE winds 10-15 kt with a few gusts up to 20 kt early this evening. As the gradient levels off, winds will gradually veer and ease overnight. Though, they could back to the NE just before daybreak Sunday, while being sustained around 5 kt. Seas will generally be 2-3 ft within 20 nm and 4-5 ft across the GA waters. But they should subside to 3-4 ft for this area after midnight. Sunday through Wednesday: The marine zones will remain under high pressure through the period. Winds should generally remain from the southeast between 5 to 10 kts with seas of 2 to 4 ft. Rip Currents: There is a Moderate Risk of rip currents for our GA beaches through this evening. && .TIDES/COASTAL FLOODING... Positive tidal anomalies and high astronomical tides from the recent full moon will lead to elevated tides through early next week. Although the astronomical high tides are lowering, coastal flooding is expected with each daytime high tide cycle along the Charleston and Colleton County coasts. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM...NED LONG TERM...NED AVIATION...NED MARINE...NED