FXUS62 KCHS 211806 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 106 PM EST Sat Feb 21 2026
.WHAT HAS CHANGED...
The key messages, marine, and aviation sections have all been updated. The Gale Watches have been upgraded to Warnings.
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.KEY MESSAGES...
- 1) Strong to severe storms possible this afternoon and
evening.
- 2) Sub-freezing temperatures return Sunday night and persist
into the mid-week.
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.DISCUSSION...
KEY MESSAGE 1: Strong to severe storms possible this afternoon and evening.
A stalled front continues to linger across the region while an upper level shortwave deepens across the Mississippi Valley. Latest radar imagery already shows ongoing showers to our north and portions of our inland counties. While these showers remain largely elevated, expect a developing sfc low to nudge the aforementioned front northward, resulting in more sfc based showers as the region becomes warm-sectored. Despite having a decent bit of cloud cover, think there will be enough WAA in place to help destabilize the atmosphere and promote a few strong to severe thunderstorms.
In terms of dynamics, latest soundings suggest SBCAPE values between 500-1000 J/kg, with some isolated areas approaching 1,500 J/kg. With PWATs near 1.5 inches and dewpoints in the mid 60s to lower 70s, certainly think we have enough moisture to work with. 0-6 km bulk shear values also remain decent, with values greater than 50 kt. So, in regard to severe weather, SPC's latest Day 1 Outlook does maintain a Marginal Risk (Level 1 of 5) for our area. As noted in the previous discussion, believe the greatest risk for severe weather will remain focused across southeastern Georgia (along/south of I-16) and possibly as far north as Beaufort and Hardeeville in southern South Carolina between 3 and 9 PM. Damaging wind gusts in excess of 58 mph and frequent lightning look to remain the primary hazards, though an isolated tornado or two cannot be ruled out.
In addition to severe weather, will see rainfall totals range between 0.50 to 1.25 inches this afternoon through Sunday morning. While most showers should remain moderate in intensity, do want to emphasize that pockets of heavier rain may still occur - which could easily support some spots receiving upwards of 0.5 inch over a 6 hour period. This could lead to brief urban, or poor drainage flooding, particularly in the Charleston and Savannah metro areas.
Otherwise, expect coverage and intensity to gradually wane through the overnight period as the front pushes eastward toward the Atlantic. Outside of a few lingering showers along the coast Sunday morning, should see largely dry conditions return across the region by Sunday afternoon.
KEY MESSAGE 2: Sub-freezing temperatures return Sunday night and persist into the mid-week.
As a cold front pushes off the coastline on Sunday morning, expect cold surface high pressure to build into the region behind it. This will yield a considerably colder airmass for the early next week with well below-normal temperatures, widespread below freezing temperatures Monday and Tuesday mornings, and wind chills dropping into the upper teens to low 20s for some areas.
Temperatures will fall Sunday afternoon with breezy northwest winds and continued cold air advection through Sunday night. By Monday morning, lows will reach the upper 20s inland and low 30s along the coastline, but gusty winds will make it feel like low to mid 20s area-wide, with upper teens possible inland. Therefore, a Cold Weather Advisory might be warranted. Highs on Monday will struggle to reach 50F (more than 15 degrees below normal for Feb.).
The coldest period is expected Monday night into Tuesday morning, with lows in the low to mid 20s inland and upper 20s near the coastline. Despite wind speeds being much lighter, wind chills will still fall into the low to mid 20s, with a few upper teens possible. Another Cold Weather Advisory may be warranted. Highs on Tuesday will moderate slightly, reaching into the low to mid 50s.
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.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
18Z TAFs: Showers and thunderstorms, perhaps a few severe, are expected to blossom across the region this afternoon, causing cigs and vsbys to lower to MVFR to IFR levels. Could even see some brief periods of LIFR occur under heavier downpours. Otherwise, expect these flight levels to become more widespread and persistent after sunset. Precipitation coverage and intensity then gradually wane from west to east overnight, with dry conditions and VFR levels expected to return by late tomorrow morning. Winds become northwesterly and quite breezy in the wake of the front, with gusts between 20-30 kt possible by the end of the period.
Extended Aviation Outlook: VFR.
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.MARINE...
Through This Evening: A stronger band of showers/thunderstorms will move through the waters. These storms could produce localized wind gusts in excess of 34 kt, isolated waterspouts, and cloud-to-water lightning. Special Marine Warnings could eventually be needed.
Low pressure will move northeast of our area tonight, dragging a strong cold front with it. This front should move through our waters early Sunday morning, then quickly shift offshore, causing winds to shift to the northwest. Strong High pressure will then start building in from the west. The interaction between these two synoptic features along with strong cold air advection will bring gale conditions to the waters Sunday afternoon into Sunday night. Therefore, we upgraded the Gale Watches to Gale Warnings. Normally, we would have Small Craft Advisories in effect before the Warnings. However, the winds ramp up so rapidly that the Advisories would only be in effect for 2-3 hours. Therefore, we just opted to start the Warnings a little earlier. We also have a Small Craft Advisory for the Charleston Harbor. Conditions improve on Monday, as High pressure gets closer to the region. Winds and seas will be noticeably lower on Tuesday as the High moves over our region.
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.CLIMATE...
Record High Temperatures:
February 21: KSAV: 84/2018
Record High Minimum Temperatures:
February 21: KCHS: 62/2023 KSAV: 63/2023
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...None. MARINE...Small Craft Advisory from 3 PM Sunday to 8 AM EST Monday for
AMZ330. Gale Warning from 3 PM Sunday to 8 AM EST Monday for AMZ350. Gale Warning from 1 PM Sunday to 8 AM EST Monday for AMZ352- 354. Gale Warning from 11 AM Sunday to 8 AM EST Monday for AMZ374.
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SST/DPB