FXUS62 KCHS 232359 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 659 PM EST Mon Feb 23 2026
.WHAT HAS CHANGED...
The Key Message regarding fire weather concerns has been removed as the Fire Danger Statement expired at 7 PM. The Aviation Section has been updated to reflect the 00Z TAF issuance.
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.KEY MESSAGES...
- 1) Cold weather with sub-freezing temperatures again tonight.
- 2) A front will bring widespread rainfall late Thursday into
Friday.
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.DISCUSSION...
KEY MESSAGE 1: 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 2: 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.
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.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Prevailing VFR at KCHS/KJZI/KSAV through the 00Z TAF period.
Extended Aviation Outlook: A front should bring flight restrictions late Thursday into Friday. Occasional flight restrictions could persist into Saturday.
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.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. The Small Craft Advisory for the Charleston Harbor was allowed to expire at 5 PM, with a Small Craft Advisory remaining in effect for all other waters through tonight and into tomorrow morning in the outer GA waters.
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.
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...None. MARINE...Small Craft Advisory until 1 AM EST Tuesday for AMZ350-352-354.
Small Craft Advisory until 7 AM EST Tuesday for AMZ374.
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CPM/ST