Area Forecast Discussion
Issued by NWS Charleston, SC

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000 FXUS62 KCHS 241147 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 647 AM EST Thu Jan 24 2019 .SYNOPSIS... A strong cold front will move offshore this morning. High pressure will then prevail through early next week. Another cold front will move through Tuesday, followed by high pressure. && .NEAR TERM /THROUGH TONIGHT/... Nearing-dawn: A wind advisory is in effect for much of coastal SC ahead of a strong cold front. The 12Z KCHS sounding measured 55 kt at 1000 ft early this morning. Rains were already tapering off from west to east prior to daybreak. Today: The surface cold front is forecast to race offshore after mid morning. Rains will end quickly from west to east over the region between 12Z-16Z. Strong southwest winds in the 25-35 mph range just ahead of the front along coastal areas at 12Z, will veer to west by later this morning in the wake of the front. Speeds will remain elevated but tend to come down from the peak gusts that occur around daybreak. Cold air advection will battle an increasing downslope component resulting in steady afternoon temps in the upper 50s over inland GA zones to the lower/mid 60s toward the coast. It is likely that most locales realize their daily max temp prior to mid morning today, despite the increasing afternoon sunshine. Tonight: A secondary surge of cold air advection this evening will result in temps falling into the 30s overnight. Light northwest winds will persist as high pressure builds from the west. Lake Winds: Cold lake waters keeping conditions largely below 15 kt ahead of the cold front, but gusty conditions were occurring around portions of the lake shores. This will change after mid morning as cold air advection initiates with the passage of the cold front and improving mixing conditions take place and winds increase across the open lake waters. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... Dry high pressure will prevail Friday through Sunday. Mostly clear skies are anticipated Friday through Saturday night, then some increasing cloudiness expected Sunday as an upper shortwave moves through. Highs will be in the low to mid 50s with lows in the upper 20s to lower 30s. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... Dry weather and moderating temperatures expected Sunday night through Tuesday as high pressure gradually shifts east. A cold front is forecast to move through late Tuesday or Tuesday night, potentially accompanied by scattered showers. There is considerable model uncertainty regarding how cold the airmass will be following the front. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... Strong low level wind fields early this morning, currently peaking prior to a cold front later this morning. Skies will clear this afternoon with VFR conditions. Gusty west winds should subside by sunset with clear skies overnight. Extended Aviation Outlook: VFR conditions will prevail. && .MARINE... A very strong low-level jet struggling to mix over the cool and relatively stable shelf waters this morning with gales ongoing over warmer waters beyond 20 NM off the SC/GA coasts. We held onto the Gale Warning along Charleston County with respect to gusts that were occurring near the land/sea interface prior to the cold front. We lowered the Gale Warning to the south of Edisto across Beaufort Waters and issued a SCA through the day into this evening when seas are forecast to subside. Winds will veer to west in the wake of the front today and this will allow seas to diminish near shore, although choppy seas are still likely with better mixing of the jetting flow. Tonight: Winds will remain elevated as cold air advection in the low levels strengthen. Speeds will mainly be below SCA levels however and seas out near the Gulf Stream will tend to subside, albeit slow. A relatively quiet marine pattern is in store for Friday through early next week as high pressure remains the dominant feature. The next wind surge is expected Tuesday night into Wednesday following the next cold front. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...Lake Wind Advisory until 4 PM EST this afternoon for SCZ045. Wind Advisory until 9 AM EST this morning for SCZ048>050-052. MARINE...Small Craft Advisory until 9 PM EST this evening for AMZ330- 352. Gale Warning until 10 AM EST this morning for AMZ350-374. Small Craft Advisory until 4 PM EST this afternoon for AMZ354. && $$ NEAR TERM... SHORT TERM...JRL LONG TERM...JRL AVIATION... MARINE...

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