AFD_CHS

FXUS62 KCHS 261747 AFDCHS

Area Forecast Discussion National Weather Service Charleston SC 147 PM EDT Thu Mar 26 2026

...DANGEROUS FIRE WEATHER CONDITIONS WITH EXTREME FIRE BEHAVIOR

LIKELY SATURDAY...

.WHAT HAS CHANGED...

All Key Messages and sections have been updated.

.KEY MESSAGES...

- 1) Near record warmth Friday.

- 2) Dangerous fire weather conditions with extreme fire

behavior likely Saturday. Fire Weather Watches/Red Flag Warnings are likely to be issued.

- 3) Hazardous conditions are likely on Lake Moultrie late

Friday night into Saturday.

- 3) Continued dry with above normal temperatures next week.

.DISCUSSION...

KEY MESSAGE 1: Near record warmth Friday. A anomalously strong 588 DM ridge centered over northern Mexico into Southwest Texas will build east through Friday. Mid-level temperatures will respond with forecast soundings showing 850 hPa temperatures climbing to around 15C with a pronounced capping/subsidence inversion noted. While a robust sea breeze will likely take shape by mid-afternoon and move steadily inland through the evening hours, a very warm day is likely with highs poised to soar into the upper 80s/lower 90s away from the coast. The daily record high at all three climate sites could be challenged with KCHS and KSAV the most likely to fall. See the climate section below for more specific details. Coastal areas will remain quite a bit cooler with the beaches likely only topping out in the upper 60s/lower 70s before the sea breeze begins to propagate inland.

KEY MESSAGE 2: Dangerous fire weather conditions with extreme fire behavior likely Saturday. Fire Weather Watches/Red Flag Warnings are likely to be issued.

A dangerous and potentially high-impact fire event could be setting up for Saturday. A strong cold front is poised to drop through the area late Friday night and should located well to the south by daybreak Saturday. Dewpoints are expected to mix out into the lower 20s inland to the upper 30s/lower 40s along the immediate coast. Local adjustments were made to lower dewpoints given models, in particular the NBM, tend to be too wet in post frontal regimes, especially with severe to extreme drought conditions in place. Gusty winds will occur behind the front with gusts expected to peak in the 20-30 mph range inland with 25-35 mph at the coast. Minimum RH values should bottom out in the 18-28% range, possibly a tad higher right at the immediate coast where a bit more of an onshore/parallel flow will prevail. The combination of gusty winds, low RH and critically dry fuels owing to the worsening drought situation suggests dangerous fire weather conditions are likely to occur for much of the day Saturday. State, military and federal land management agencies have already observed some extreme fire behavior with controlled burns and a few wildfires over the past few days (mainly once RH drops below 60%) and with the situation likely to get worsen Saturday, the fire situation could become rather volatile with high-impact even if the highest winds and lowest RH do not perfectly align.

Per coordination with neighboring NWS offices as well as state and federal partners, a Fire Weather Watch will likely be issued for most, if not all, of the Lowcountry and Southeast Georgia overnight Refer to the Georgia and South Carolina Forestry Commissions for any burn bans are in effect.

KEY MESSAGE 3: Hazardous conditions are likely on Lake Moultrie late Friday night into Saturday.

Winds will increase on Lake Moultrie late Friday night into Saturday behind a southward moving cold front. Conditions could get hazardous on the open lake waters with winds reaching as high as 20-25 kt with gusts up to 30 kt. Wave action could be significant with waves reaching 2-3 ft at times, especially over the central and southern portions of the lake. A Lake Wind Advisory will likely be needed.

KEY MESSAGE 4: Continued dry with above normal temperatures next week.

High pressure to the north will gradually shift east into the Atlantic next week. A southerly return flow coupled with a building upper ridge will support dry conditions with above normal temperatures.

.AVIATION /13Z THURSDAY THROUGH MONDAY/...

26/18z TAF Discussion: KCHS/KJZI/KSAV: VFR through 27/18z.

Extended Aviation Outlook: Gusty winds behind a dry cold front on Saturday. Gusts could exceed 20 kt.

.MARINE...

The main concern through the weekend is the increasing potential for gales late Friday night into Saturday as a cold front shifts south through the area. The combination of post frontal cold air advection coupled with a typical pinching of the pressure gradient with building high pressure to the north should support about a 12-18 hour period of gale conditions. Peak winds should occur Saturday morning where winds could reach as high as 25-30 kt with gusts 35-40 kt nearshore and 30-35 kt offshore with gusts 40-45 kt offshore. Seas will build quickly in the northeasterly flow, peaking 6-9 ft nearshore waters and 9-12 ft over the Georgia offshore waters Saturday night. Conditions will steadily improve Sunday as the pressure gradient relaxes, although it may take until Monday before seas drop below 6 ft. Per coordination with neighboring offices, Gale Watches have been posted for all waters, including the Charleston Harbor from late Friday night into Saturday, except into Saturday night for the Georgia offshore waters.

High Surf: Breaking wave heights could reach 5-6 ft along parts of the Georgia coast Saturday afternoon into Sunday. A High Surf Advisory may be needed.

.CLIMATE...

Record High Temperatures:

March 27: KCHS: 87/2021 KCXM: 81/2021 KSAV: 89/2021

.CHS WATCHES/WARNINGS/ADVISORIES...

GA...None. SC...None. MARINE...Gale Watch from Saturday morning through Saturday afternoon

for AMZ330. Gale Watch from Saturday morning through Saturday afternoon for AMZ350-352-354. Gale Watch from Saturday morning through late Saturday night for AMZ374.