FXUS62 KCHS 021109 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 709 AM EDT Sat Nov 2 2024
.SYNOPSIS...
A backdoor cold front will move through late today into Sunday. High pressure will then return through the middle of next week.
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.NEAR TERM /THROUGH TONIGHT/...
Early morning update: Keeping an eye on a few pockets of showers in the SC coastal waters...some of which are under 20 NM from shore and drifting westward. Trends suggest they are falling apart, but we did have some similar shower activity move inland yesterday morning. Keeping the forecast dry for the moment.
Previous discussion... Overnight composite analysis reveals low amplitude upper level ridging across the Gulf Coast and southeast region and associated ridge axis extending up into the upper Midwest. Large expanse of surface high pressure is centered over the eastern Great Lakes and covers the entire eastern CONUS while some degree of wedging extends down through the southeast. Evidence of a boundary stretches through the western Carolinas into northern Georgia. Other than periodic showers in the offshore waters, quiet weather continues to prevail.
Surface high pressure is expected to strengthen slightly while shifting eastward through tonight. This will further develop wedging down through the southeast and ultimately drive cooler/drier air into the region heading into Sunday.
Today: Another overall quiet and warm day is on tap with temperatures warming into the lower to middle 80s (per forecast soundings and MOS products)...a good 10 degrees or so above normal for early November. Mainly dry weather inland although given the anticipated development of a fairly deep mixed layer and subsequent touch of high based CAPE, there is some support for a few showers to develop well inland later this afternoon. Morning forecast package will introduce a small area of isolated showers to cover that possibility.
Tonight: Wedging will continue to build through the southeast region while cooler and drier air get advected down through the region on increasing northeasterly flow. The increased surface winds and a drier air mass should end the fog threat that we've seen over the last few nights. Temperatures will dip into the upper 50s to lower 60s inland...warmer along the coast.
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.SHORT TERM /SUNDAY THROUGH TUESDAY/...
High pressure aloft will prevail over the local forecast area, centered over the Western Atlantic. This pattern aloft will persist into the middle of next week. At the surface a stalled front in the vicinity of the forecast area could trigger some isolated showers on Sunday, mainly over the coastal waters. Some isolated showers may reach the beaches Sunday afternoon. Thereafter high pressure centered over New England will build into the region from the north and a dry forecast has been maintained. Temperatures Sunday will be close to normal, generally in the mid to upper 70s. Overnight lows on Sunday will be in the upper 50s inland and low to mid 60s along the coastal counties. Temperatures will then gradually warm into the week, returning to the low 80s by Tuesday.
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.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
Ridging aloft will dominate the synoptic pattern across the southeastern states through the middle of the week. At the surface high pressure will prevail through Thursday. A cold front is forecast to push through the region on Thursday, bringing the region it's first real shot at rain in a while. Ensemble models have come into better agreement that the region should see measurable precipitation. Temperatures will remain above normal through the period.
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.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
KCHS/KJZI/KSAV: Early this morning: Some visibility restrictions are noted early this morning across the region, although bonafide fog (1/2sm or less) has not materialized as of yet. However, climatologically favored time of the day for fog is over the next hour or so (around sunrise). Will continue to mention some vsby restrictions at KCHS through 13Z. KJZI and KSAV are probably fine at this point given some higher clouds that have migrated over those terminals.
Development of at least scattered Cu is likely by afternoon and an isolated shower cannot be ruled out inland. Northeast winds under 10 knots veer more easterly during the afternoon.
Tonight: Push of cooler/drier air takes shape through the night. Forecast soundings and RH forecasts suggest there may be a window of time for low cloud cover to develop at the terminals as the cooler air slides down into the region. Could lead to a period of MVFR or even IFR conditions overnight.
Extended Aviation Outlook: Prevailing VFR.
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.MARINE...
Surface high pressure located in the eastern Great Lakes will strengthen through tonight and further develop wedging down through the southeast region. This will lead to increasing northeasterly winds through tonight and seas 2 to 4 feet today building to 3 to 5 feet tonight.
Sunday through Thursday: High pressure will build into the region from the north Sunday and into the middle of next week. Small Craft Advisories may be required for some waters as NE gusts approach 25 knots on Sunday. Additionally, seas are forecast to increase to 4 to 6 ft across most waters on Sunday. As high pressure builds into the region seas will remain elevated and E winds will remain around 15 to 20 knots. Small Craft Advisory conditions are forecast to remain through at least the middle of next week.
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...None. MARINE...None.
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NEAR TERM...Adam SHORT TERM...CPM LONG TERM...CPM AVIATION...Adam/CPM MARINE...Adam/CPM