FXUS62 KCHS 231733 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 1233 PM EST Mon Feb 23 2026
.WHAT HAS CHANGED...
All sections have been updated. Key Message 4 was added.
&&
.KEY MESSAGES...
- 1) Breezy winds with low relative humidity values enhances
fire weather concerns through sunset.
- 2) Hazardous conditions on Lake Moultrie will continue through
late afternoon.
- 3) Cold weather with sub-freezing temperatures again tonight.
- 4) A front will bring widespread rainfall late Thursday into Friday.
&&
.DISCUSSION...
KEY MESSAGE 1: Breezy winds with low relative humidity values enhances fire weather concerns through sunset.
Sustained northwesterly winds of 15 to 20 mph with gusts up to 25-30 mph are expected through the evening as a low pressure system shifts farther away and surface high pressure builds into the region. This downslope flow regime will continue to usher in a drier airmass and yield relative humidity values between 25-30% this afternoon. Despite the measurable precipitation this past weekend, these conditions will support elevated fire weather concerns today. A Fire Danger Statement continues through until 7 PM.
KEY MESSAGE 2: Hazardous conditions on Lake Moultrie will continue through late afternoon.
Winds continue to surge on Lake Moultrie this afternoon due to lingering cold air advection and an enhanced pressure gradient. Winds at PNOS1 on the south side of the lake at Pinopolis is still showing sustained winds around 20 kt with frequent gusts in the mid-upper 20s. THe Lake Wind Advisory has been extended until 5 PM.
KEY MESSAGE 3: Cold weather with sub-freezing temperatures again tonight.
Modified arctic high pressure centered over the central Plains this afternoon will south into the north-central Gulf coast overnight. The gradient between the high and the nor'easter departing to the Northeast U.S. will keep some degree of wind in place through the night. There are indications the gradient may relax just enough before daybreak to allow for least a partial decoupling of the boundary layer, but guidance is certainly struggling with how much of this will occur. The 23/13z NBM is running at the very top end or even outside of the warmer side of the interquartile range (IQR) of the various guidance and was considered an outlier. A blend of the colder statistical and deterministic guidance was preferred for and yields lows very similar to the previous forecast; ranging from the mid 20s inland to the the lower 30s at the beaches. A few lower 20s are possible away from the coast where some localized, full boundary layer decoupling occurs. As winds diminish with the approach of the diurnal minimum, wind chills are expected to bottom out 20-25 degree range or just above Cold Weather Advisory criteria. A few spots could briefly drop into the upper teens just right around daybreak, but durations should be pretty brief and transient. A Cold Weather Advisory will not be issued for this reason.
KEY MESSAGE 4: A front will bring widespread rainfall late Thursday into Friday.
The mid-levels will consist of nearly zonal flow over the Southeast U.S. Thursday morning. Troughing will develop to our west Thursday night, with its axis stretching roughly from the TN Valley southward on Friday and Friday night. At the surface, High pressure will be far offshore Thursday morning. Meanwhile, Low pressure will be centered over the Mid MS Valley, with an attached warm front located well to our north and a cold front well to our west. The Low will shift eastward Thursday, dragging the cold front with it. This will usher deeper moisture into our region. Models generally have scattered showers overspreading our far inland counties Thursday morning, perhaps remaining over this general area through Thursday afternoon. Showers should shift eastward Thursday evening, with widespread rainfall expected late Thursday night into Friday morning. The widespread showers should shift closer to the coast Friday afternoon, with coverage decreasing further inland. There are some differences regarding how fast or slow the showers clear out from our area, ranging Friday night through Saturday. This aspect of the forecast will need to be refined. It's still too early to determine total rainfall amounts, but initial indications are we're not expected flooding rains, especially considering the ongoing drought in place. Additionally, a few rumbles of thunder are possible ahead of the front. High temperatures should be a few degrees above normal during this time frame.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
23/18z TAF Discussion: KCHS/KJZI/KSAV: VFR through 24/18z.
Extended Aviation Outlook: A front should bring flight restrictions late Thursday into Friday. Occasional flight restrictions could persist into Saturday.
&&
.MARINE...
Through Tonight: Winds will continue to slowly subside across the waters tonight as the pressure gradient between inland high pressure and departing low pressure eases. Small Craft Advisories were extended by about 3-6 hours across the Charleston Harbor and nearshore waters based on current trends. The Gale Warning for the Georgia offshore waters was also downgraded to a Small Craft Advisory and is in effect through daybreak Tuesday.
Tuesday and Wednesday: Winds may approach Small Craft Advisory levels across mainly the Georgia offshore and both South Carolina nearshore waters Wednesday in response to a re- tightening of the pressure gradient between departing high pressure to the southeast and and the formation of a lee-side trough across the Upstate into the North Carolina Foothills.
Thursday and Friday: A front will approach from the west on Thursday, causing winds and seas to increase to Small Craft Advisory levels across most our our ocean zones. These conditions will persist into Thursday night. The front is expected to shift through the waters on Friday, then offshore Friday night, causing winds and seas to trend lower.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...Lake Wind Advisory until 5 PM EST this afternoon for SCZ045. MARINE...Small Craft Advisory until 5 PM EST this afternoon for AMZ330.
Small Craft Advisory until 1 AM EST Tuesday for AMZ350-352-354. Small Craft Advisory until 7 AM EST Tuesday for AMZ374.
&&
$$