Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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809 FXUS62 KCHS 261704 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 104 PM EDT Sun May 26 2024 .SYNOPSIS... Hot conditions are expected through Memorial Day. A cold front will move into the region Monday night and stall into mid week. High pressure will return for the second half of the week. && .NEAR TERM /THROUGH TONIGHT/... This afternoon through this evening: At the surface high pressure is located to the east while to the west there are two features of note. Hand analysis from 12Z depicts a shortwave trough on the lee side of the Appalachian Mountains as well as a much weaker shortwave across MS/AL. The trough to the lee of the mountains is the focus of possible precipitation this afternoon, as the shortwave across MS/AL is quite weak and likely will not be enough forcing to spur showers/thunderstorms. Ongoing convection over Kentucky, associated with the shortwave, will continue into this afternoon, with additional showers and thunderstorms possibly forming over the SC Midlands. Some of those showers and thunderstorms could brush some of the far inland counties of the CWA as well as make a run for the Charleston Tri-County. The thunderstorm risk this afternoon is very conditional, if storms are able to form mesoanalysis suggests that DCAPE values are upwards of 1200 J/kg, along with 40 knots of effective shear. This would lead to a threat of damaging wind gusts. Low level lapse rates are forecast to be around 7 to 7.5 C/km, which would also lead to a marginal hail threat. It will be another seasonably hot and humid day with highs warming into the lower 90s with a few mid 90s possible in a few areas. These temperatures combined with moderate levels of humidity will support heat indices in the 98-101 range. Overnight: Dry conditions will prevail into early Monday morning once evening convection dissipates. A little ground fog could develop prior to daybreak, but no major issues/impacts are expected. It will be warm/humid night with lows only dropping into the lower 70s with mid 70s at the coast and beaches. The record high minimums could be challenged, mainly at the Charleston AFB/International Airport (KCHS) and Downtown Charleston (KCXM), but current data suggest values will fall just short of record levels. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... The forecast area will be situated between offshore high pressure and a cold front approaching from the west on Monday. Aloft, broad troughing shifts towards the East Coast, pushing the ridge axis offshore. Consensus keeps at least the first half of the day dry, then upstream convection could move into the area later in the afternoon and into the evening/overnight. Still unsure of how much coverage there will be when this occurs but at least scattered showers and thunderstorms will be possible. Some of this activity could be more organized when it arrives. Primary threat with any stronger storms would be damaging wind gusts. Otherwise, expect another hot day with highs reaching the low 90s in most locations. Lows Monday night will largely be around 70 or in the lower 70s. The aforementioned front will then stall in the vicinity into mid week. PWats fall and trends have continued to show a drier forecast for Tuesday. Shouldn`t see more than just isolated showers and thunderstorms, particularly along the coast. A dry forecast is in place for Wednesday. Highs both days peak in the upper 80s to lower 90s. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... High pressure will be the primary surface feature Thursday into the weekend. Aloft, mid level wave passes over the Northeast and Mid- Atlantic, before shifting offshore late week. This period should be mostly dry, aside from some diurnal rain chances returning over the weekend. Temperatures will be near normal. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Prevailing VFR through the 18Z TAF period at KCHS/KJZI/KSAV. Showers and thunderstorms are possible this afternoon, however the best chances remain inland from the terminals. KCHS/KJZI have the best chance at seeing a shower/tstorm, however confidence in direct impacts to the terminals remain low so there is no mention in the 18Z TAFs. Extended Aviation Outlook: Brief flight restrictions are possible in showers/thunderstorms Monday afternoon into Tuesday. && .MARINE... Today: West winds will turn more southerly this afternoon with the development of a modest resultant sea breeze circulation. Winds along the land/sea interface, including Charleston Harbor, could get a bit elevated for a few hours this afternoon with winds in the Harbor reaching 15 kt with gusts to 20 kt. Onshore winds coupled with an outgoing tide could make for locally rough conditions in the Harbor late this afternoon. Seas will average 1-2 ft. Tonight: Southerly winds around 10 kt will persist through the night. A few tstms could move off the Charleston County coast later this evening bringing a risk for convective wind gusts in excess of 34 kt and cloud-to-water lightning. Monday through Friday: Marine conditions remain below Small Craft Advisory levels through the week. South to southwest will largely persist through midweek until a cold front pushes east of the waters. High pressure will be the dominant feature for late week. Winds will average 15 knots or less and seas 2-3 feet, with occasional 4 feet early in the week. && .CLIMATE... Record High Minimum Temperatures: May 27: KCHS: 76/1991 KCXM: 79/2019 KSAV: 77/1878 May 28: KCHS: 76/2000 KCXM: 80/2000 KSAV: 76/1885 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE...