FXUS62 KCHS 072330 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 630 PM EST Sat Mar 7 2026
.WHAT HAS CHANGED...
The Aviation section has been updated for the 00z TAF issuance.
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.KEY MESSAGES...
- 1) Patchy to areas of fog possible across Southeast South
Carolina and Southeast Georgia tonight into Sunday morning.
- 2) Unseasonably warm temperatures continue through Wednesday,
along with increased rain chances.
- 3) A cold front may bring widespread rainfall on Thursday.
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.DISCUSSION...
KEY MESSAGE 1: Patchy to areas of fog possible across Southeast South Carolina and Southeast Georgia tonight into Sunday morning.
Conditions continue to be supportive for the development of fog and low stratus overnight, though not quite as conducive as the last few nights. The pressure gradient will be a bit tighter tonight, supporting stronger and more persistent south to southwest flow in the low-levels. This should reduce the coverage of fog compared to the last few nights. The main concern will be for fog development across the nearshore coastal waters which then advects inland along the coast. Wind directions will be more in the 190-210 degree range, which will prevent too much inland movement, and more broadly favor the immediate coastline. Dense Fog Advisories could again be needed for portions of the area.
KEY MESSAGE 2: Unseasonably warm temperatures continue through Wednesday, along with increased rain chances.
Deep-layered high pressure extending across the western Atlantic will prevail across the Southeast United States into the middle of next week. A stalling/dissipating front will be upstream Monday, followed by High pressure in the wester Atlantic Tuesday and Wednesday. This pattern will usher moisture into our area through the middle of next week. Likewise, the NBM generally has slight chance to chance POPs Sunday through Tuesday. Any showers/thunderstorms should be fairly quick moving, leading to low rainfall amounts. No severe weather is expected.
The main story during this time period will continue to be the unseasonably warm temperatures. Highs will range from near 80 degrees to the upper 80s, except cooler temperatures along/near the coast. Wednesday should be the hottest day across our entire area with a few spots across our interior GA counties making a run for the 90 degree mark. Lows each night will generally be in the lower 60s.
KEY MESSAGE 3: A cold front may bring widespread rainfall on Thursday.
The mid-levels will consist of a trough axis roughly over the MS River Valley early Thursday morning. Models vary on its eastward speed and location, but the general consensus has the trough quickly moving over the East Coast later in the day, then off the coast Thursday night. This matters because the energy will be transferred to a cold front, which appears to move through our area on Thursday. There will be a deep plume of moisture ahead of this front. The combination of the moisture and lift may generate widespread showers across our area. Given the unseasonably warm temperatures ahead of the front, there should be enough instability to fire off some thunderstorms. Though, it's too early to determine how strong they will be. Likewise, it's too early to determine rainfall amounts. But any showers/storms appear to be progressive in speed.
High pressure behind the front will bring drier conditions along with a return to seasonal temperatures.
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.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
The 00z TAF period begins with VFR conditions at KCHS, KJZI, and KSAV. The main forecast challenge will again be fog and low stratus. Conditions are expected to be a bit different tonight, mainly due to winds being more south to southwesterly and stronger. This should favor more stratus than fog overall. KCHS and KSAV should still see a period of IFR stratus, but KJZI is trickier with its closer proximity to the coast and any marine fog that develops. KJZI could see lower visibilities and perhaps even some dense fog. The main time period of concern is still 09-13z, with quick improvement back to VFR by 14z and onward. Then in the afternoon, there is good support from hi-res models for shower and thunderstorm development. This activity will likely be late afternoon and early evening and could be close to all 3 TAF sites. Showers and storms could need to be explicitly mentioned in the TAF's with future issuances.
Extended Aviation Outlook: Low stratus/fog could bring restrictive ceilings and visibilities during the overnight into the early morning hours early next week. Brief flight restrictions are possible due to showers and thunderstorms next week. A cold front should bring flight restrictions on Thursday.
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.MARINE...
Tonight: The main issue will be the continuation of sea fog across nearshore waters overnight. Latest webcams and visible sat imagery indicate fog has dissipated and we have cancelled the Dense Fog Advisory for the nearshore GA waters. Guidance does suggest the redevelopment of sea fog (some dense) returning across nearshore waters overnight, and to a lessor degree across the Charleston Harbor, but confidence is somewhat less for all nearshore waters overnight given slightly stronger low- lvl flow across the region. Conditions will continue to be monitored for Dense Fog Advisories across these waters overnight into early daylight hours Sunday. Otherwise, fairly light southeast winds will veer to the south and southwest tonight as the gradient between high pressure centered well offshore and an approaching cold front tightens.
Sunday through Thursday: High pressure will remain the dominant weather feature across our local waters next week, favoring a south/southwest wind in the 10-15 kt range and seas generally between 2-4 ft, well below Small Craft Advisory thresholds. A cold front will approach late Wednesday, causing winds and seas to increase to Small Craft Advisory levels across all of our ocean zones. Gusts to gale force cannot be ruled out behind the cold front on Thursday.
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.CLIMATE...
Record High Temperatures:
March 8: KCHS: 86/1974 KCXM: 86/1951 KSAV: 86/1974
March 9: KCHS: 87/1974 KCXM: 84/1974 KSAV: 88/1974
March 10: KCHS: 90/1974 KCXM: 87/1974 KSAV: 91/1974
March 11: KCHS: 85/2015 KCXM: 82/1997 KSAV: 87/2015
Record High Minimum Temperatures:
March 8: KCHS: 63/2022 KCXM: 65/2022 KSAV: 65/1880
March 9: KCHS: 66/2022 KCXM: 65/2022 KSAV: 65/2022
March 10: KCHS: 64/1974 KCXM: 65/1974 KSAV: 63/1909
March 11: KCHS: 63/2015 KCXM: 64/2016 KSAV: 64/1974
March 12: KCHS: 62/1985 KCXM: 64/1973 KSAV: 65/1973
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...None. MARINE...None.
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BSH