FXUS62 KCHS 012037 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 337 PM EST Sat Feb 1 2025
.SYNOPSIS...
High pressure will build over the area this weekend and prevail through the middle of next week. Then a cold front could approach around mid to late next week.
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.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
KCLX detected an area of weak returns along the GA/SC coast this afternoon. The weak returns were likely associated with a developing sea breeze. Recent runs of the HRRR indicates that the sea breeze will advance inland through the rest of this afternoon into much of this evening. Temperatures should peak between 68 to 73 degree as the sea breeze approaches this afternoon. In the wake of the sea breeze, temperatures will begin to cool and winds will become light and variable.
Tonight, high resolution guidance indicates that a backdoor cold front may reach the South Santee River around midnight, then the Savannah River by daybreak Sunday. In the wake of the front, winds will shift from the northeast between 5 to 10 mph. HREF and forecast soundings indicate that cloud cover will gradually increase through tonight. Low temperatures are forecast to range from the low to mid 40s inland to the upper 40s along the coast.
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.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
Sunday: Northern New England high pressure will wedge into the Southern Appalachians. Weak shortwave energy aloft, and a coastal trough will result in partly cloudy skies. Light rain showers should largely remain offshore, but could approach the Charleston County coast. Cold air advection associated with a moderate northeast flow will result in a relatively large range in high temps with upper 50s to near 60 along the Santee River in SC while far southern GA areas climb into the lower 70s. The beaches will stay cool, in the upper 50s to lower 60s. Overnight lows will be in the low/mid 40s.
Monday and Tuesday will feature zonal flow aloft while a broadening surface high shifts east and sets up over the western Atlantic. Strengthening southerly flow and the resulting thickness advection will yield above normal temps both days. Monday's highs will reach low to mid 70s inland and low 60s along the coast. Lows will reach the upper 40s to low 50s. An even warmer day is expected Tuesday with highs in the upper 70s across South Carolina and lower 80s across Georgia. Some locations could even rival record highs (see Climate section). Increasing surface dewpoints moving over relatively cool shelf waters could allow sea fog development, which could move onshore into the coastal counties.
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.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A strong 500 mb ridge centered over Cuba will remain over the Deep South through late next week while broad surface high pressure remains to the east. The combination of steady south winds, plenty of insolation, and mild thicknesses should result in very warm temperatures. Lows will generally be in the 50s while highs will reach the upper 70s/low 80s away from the immediate coast. We could even reach daily record highs on some occasions (see Climate section). A backdoor cold front could approach the area later next week.
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.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
18Z TAFs: VFR conditions expected across the terminals through the TAF period. Northwest winds are forecast to remain through at least mid-afternoon. Recent runs of the HRRR indicate that weak sea breeze will advance across the coastal counties late this afternoon into this evening. The TAFs will indicate that winds will become light and variable by late this afternoon through late tonight. A backdoor cold front may slide across the terminals around 7Z, resulting in winds shifting from the northeast between 5 to 10 kts. Northeast winds with at least a BKN deck of high clouds should remain through Sunday morning.
Extended Aviation Outlook: Fog and/or low stratus possible during the overnight periods.
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.MARINE...
Tonight: High resolution guidance indicates that a backdoor cold front may reach the South Santee River around midnight, then the Savannah River by daybreak Sunday. In the wake of the front, winds across the Charleston County nearshore waters will shift from the northeast and increase to 15 to 20 kts with gusts to 25 kts. In addition, seas are forecast to build to 3 to 6 ft across the Charleston County nearshore waters after midnight. The gusty winds and seas of 6 ft or more across the nearshore waters between the Santee and Edisto Rivers will be highlighted with a Small Craft Advisory starting at 11 PM. Elsewhere, northeast winds between 10 to 15 kts will spread across the marine zones tonight. Seas should generally range between 2 to 4 ft.
Sunday through Thursday: Outside of a transient coastal trough Sunday, high pressure will prevail over the local waters. Sunday morning, 6 ft seas and 25 kt gusts will linger in the Charleston nearshore waters due to a moderate northeast gradient. A Small Craft Advisory for this marine zone is in effect through mid-morning. Otherwise, a surface high over the western Atlantic will keep winds/seas well below advisory levels in the local waters through the period. The only other concern is possible sea fog beginning Sunday night or Monday as higher dewpoints move across water temps around 50 degrees.
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.CLIMATE...
Record High Temperatures:
February 4: KSAV: 81/1990
February 5: KSAV: 82/2008
February 6: KCHS: 78/2019 KSAV: 82/2008
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...None. MARINE...Small Craft Advisory from 11 PM this evening to 10 AM EST
Sunday for AMZ350.
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NEAR TERM...NED SHORT TERM...BRS LONG TERM...BRS AVIATION...BRS/NED MARINE...BRS/NED