FXUS62 KCHS 100548 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 1248 AM EST Sat Jan 10 2026
.SYNOPSIS...
High pressure will persist today, then a cold front will move through on Sunday. High pressure will rebuild through the middle of the week, then another cold front will move through Thursday.
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.NEAR TERM /THROUGH TONIGHT/...
Tonight: The region remains in the southwest sector of surface high pressure that is shifting eastward across the Atlantic while a cold front traverses the Deep South. As the cold front remains well off to our west, no rain is expected, but fog remains the main concern heading into the overnight period. A vast majority of guidance shows a bank of sea fog redeveloping early evening, which is then advected onto land as temperatures cool overnight. There was some evidence via webcams showing sea fog developing just off the Hunting Island, SC and Hilton Head Island, SC coast prior to sunset, which could become the main focus of sea fog drifting onshore initially within an easterly wind early-mid evening. Given relatively weak surface flow and abundant moisture in the boundary layer, radiation fog could also form across areas away from the coast as well overnight. Sfc dewpts are notably higher than the previous night (lower 60s) and condensation pressure deficits are very favorable for another round of dense fog overnight. However, low-lvl wind fields are a bit stronger than the previous night, which could delay the overall development of dense fog until late evening or during the second half of the night, at least away from the beaches. The greatest risk for dense fog remains across areas generally along and east of I-95 across Southeast South Carolina into Southeast Georgia. A Dense Fog Advisory could eventually be needed.
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.SHORT TERM /SUNDAY THROUGH TUESDAY/...
Saturday: Fog, some dense, could linger over land into the mid to late morning hours with at least a risk for patchy fog impacting the beaches into the afternoon. The region will still be fully embedded within the warm sector of an approaching cold front as a strong storm system moves across the Great Lakes region. An isolated shower or two from off the Atlantic could brush the coastal areas, but guidance is not overly keen on this scenario, especially as low- level wind fields veer with time. No mentionable pops were included given the overall low chance for anything measurable. Rain chances will increase Saturday evening as the rain band associated with the front approaches from the west. The overall model trends have not changed too much and still favor the better rain chances occurring across the far interior as the decaying frontal rain band marches east. Guidance has been fairly consistent in showing the corridor of greatest forcing associated with both the right entrance region of the polar jet and DPVA ahead of the Great Lakes upper trough passing by well to the north and northwest, but a bit more forcing is noted in 09/12z model cross sections. This may translate into the line holding together a bit more as it exits the South Carolina Midlands, CSRA and central Georgia even though the line will likely be in a steady weakening phase as it moves into the Lowcountry and Southeast Georgia. How much of the line will dissipate before reaching the coast is still uncertain. The pop gradient was tightened a bit based on the latest trends, ranging 40-70% well inland to 20-40% coast, but higher pops may eventually be needed for some areas once this period enters into the temporal window of some of the higher resolution CAMs. Another day of near record warmth is expected with highs ranging from the lower 80s west of I-95 to the mid 60s at the beaches. See the climate section below for specific records. Lows Saturday night will range from the lower 50s in the Allendale- Reidsville corridor to the mid-upper 50s elsewhere.
Sunday and Monday: The cold front will clear the coast by mid- morning with the risk for isolated to scattered showers lingering until FROPA. Otherwise, dry and cooler conditions will prevail as a modified Canadian airmass settles into the Southeast States even as the upper flow aloft remains somewhat cyclonic. It could be a bit breezy Sunday afternoon with the onset of modest cold air advection and winds on Lake Moultrie could get close to Lake Wind Advisory criteria (40% NBM probability for frequent gusts to 25 kt). Highs Sunday will occur early in the day, peak in the upper 50s inland to the mid 60s at the coast, with temperatures either leveling out or even falling a bit in the afternoon as temperatures aloft cool. Lows Sunday night will drop back closer to climatological normals, ranging from the upper 20s well inland to the upper 30s at the beaches. Monday will offer considerably cooler highs with temperatures maxing out in the lower-mid 50s.
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.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
Rain chances will begin to increase mid-late week as another cold front pushes offshore and a deep upper trough initiates strong cyclogenesis off the Eastern Seaboard. More seasonable temperatures can be expected for much of the week with temperatures averaging near to slightly below normal for mid-January.
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.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
Prior to the 6Z TAFs, observations and satellite have indicated some degree of fog and stratus at the terminals, especially KCHS and KJZI. Based on HRRR sfc condensation pressure deficits and MOS, IFR and LIFR ceilings may develop early this morning, occurring with rounds of IFR fog. Ceilings should reach the lowest levels around dawn. As a cold front approaches from the west today, southwest winds should begin to strengthen during the early daylight hours, peaking early this afternoon. Momentum transfer should yield gusts into the teens to low 20s through this afternoon. The strengthen winds should mix out low ceilings this morning, with VFR by 14Z. Southwest winds should continue through this evening, with gusts decreasing into the teens by late this afternoon.
Extended Aviation Outlook: A band of showers with a cold front may bring reduced vsbys Saturday night into early Sunday morning. Gusty northwest winds are possible Sunday afternoon.
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.MARINE...
Tonight: Recent webcam imagery indicated sea fog attempting to redevelop off the Hunting Island and Hilton Head Island coastline across southern South Carolina nearshore waters early this evening, which could be the precursor to sea fog expanding and becoming dense across nearshore waters by mid-late evening, and in the Charleston Harbor late evening and overnight. Light onshore winds (5-10 kt) could initially limit sea fog development and/or expansion across local waters this evening, but sfc winds are forecast to become more southerly around 10 kt overnight, suggesting a more favorable setup of warm and moist air traversing across cooler waters despite a slightly higher increase in wind speed. Trends will continue to be monitored for potential Marine Weather Statements and/or a Dense Fog Advisory. Seas should gradually build to the 1-2 ft range overnight.
Saturday through Tuesday: There are two main concerns for the period. Some degree of fog, possibly dense with vsby 1 NM or less, could linger across the coastal waters Saturday as warm, moist airmass holds in place over the cool Atlantic shelf waters. The risk for reduced vsbys should end by Saturday night as a low-level wind fields veer and increase ahead of an approaching cold front.
There is a risk for both winds and seas reaching Small Craft Advisory criteria Sunday afternoon through early Monday morning as cold air advection spread east across the waters in the wake of a cold front. The probability for winds reaching frequent gusts to 25 kt is averaging about 40-60% across the nearshore waters and 70-90% over the Georgia offshore waters.
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.CLIMATE...
Record High Temperatures: January 9: KCHS: 78/2012 KSAV: 77/2008
January 10: KCHS: 79/2008 KSAV: 81/1972
Record High Minimum Temperatures: January 10: KCHS: 60/1974 KCXM: 62/1974 KSAV: 63/1937
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...Lake Wind Advisory from 11 PM this evening to 7 PM EST Sunday
for SCZ045.
MARINE...Small Craft Advisory from 9 AM to 8 PM EST Sunday for AMZ330.
Small Craft Advisory from 2 AM Sunday to 6 AM EST Monday for AMZ350. Small Craft Advisory from 9 AM Sunday to 6 AM EST Monday for AMZ352-354-374.
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NEAR TERM... SHORT TERM... LONG TERM... AVIATION...NED MARINE...