


Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --597 FXUS62 KCHS 010145 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 945 PM EDT Mon Jun 30 2025 .SYNOPSIS... A front is expected to move into the area by Wednesday and could then linger in the vicinity into the weekend. && .NEAR TERM /THROUGH TONIGHT/...-- Changed Discussion --Showers and thunderstorms from this evening have now finally dissipated over Southeast Georgia. As the region remains on the backside of this Bermuda High centered offshore, a upper-level trough will set up over the Great Lakes overnight. Simultaneously, a weak shortwave will shift westward towards the Atlantic seaboard. At the surface, southwest winds will remain elevated between this pinched pressure gradient. This will be enough to keep any fog from developing overnight. Skies will keep mostly clear, with coverage increasing across the far interior Georgia counties in the early morning (~10-11Z). Low temperatures will be near normal, mainly in the low to mid 70s, except a bit higher at the beaches and immediate coastline.-- End Changed Discussion --&& .SHORT TERM /7 AM TUESDAY MORNING THROUGH THURSDAY/... Tuesday through Thursday: Aloft, we begin Tuesday with a baggy upper trough that steadily becomes more well defined and sharper into Wednesday as a shortwave passes by to the north. At the surface, Tuesday will see the area situated between the subtropical high to the east and a front to the west that stretches from the eastern Great Lakes into the lower MS Valley. This front is expected to gradually shift closer to the area through Wednesday and perhaps remain in the vicinity through Thursday. Also of note, precipitable water values are expected to surge for Wednesday with the entire forecast area within an area of 2.25" or higher values. Concerning the coverage of convection, the overall trend is expected to be increasing especially for Wednesday when we anticipate seeing the best combination of forcing and moisture. Slow moving storms and the overall expected increased coverage for Wednesday will also likely yield the greatest potential for locally heavy rainfall across the area. Overall, there is no notable severe threat, though there could always be a strong to marginally severe storm as outflow boundaries interact. Temperatures are expected to be near normal for Tuesday, then perhaps a bit below normal on Wednesday thanks to the increased shower and thunderstorm coverage. Thursday should be back to near or slightly above normal. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... The pattern for Friday through the weekend and into early next week looks to be pretty typically of summer. The one thing to keep an eye on is that some model guidance keeps the mid/late week front lingering along the coast and attempts to develop an area of low pressure along it. As such, the northeast Gulf Coast and Southeast coast are currently highlighted in NHC`s Tropical Weather Outlook with a low chance of tropical development over the next 7 days. But for now, the forecast highlights low 90s for highs each day with scattered diurnal convection. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... 00Z TAFs: Convection from this evening has now dissipated at all terminals and now settling into a clear night. As the region remains on the backside of this surface high pressure centered offshore, an upper-level trough will float into the Great Lakes region, with the southern periphery over the Southeastern CONUS. This will result in pinched pressure gradient over the region, and winds might become quite gusty (20-22KT) over Tri-County tomorrow by the late morning/early afternoon. The highest chance of convection will be across inland/coastal Georgia in the afternoon as the seabreeze pushes inland. Thus, convection was left out of the forecast at this time for KCHS/KJZI. Extended Aviation Outlook: Mostly VFR. There is potential for brief impacts from thunderstorms each afternoon and evening with the best chances coming during the mid week time period as a front moves into the region. && .MARINE...-- Changed Discussion --Tonight: As the local waters remain on the backside of this Bermuda High, the pressure gradient will continue to tighten and allow southwesterly winds to remain elevated at 10 to 15 kt with gusts up to 20 kt. Weak south-southeasterly swell with a 4 to 6 second period will dominate the local waters tonight, and allow for a choppy set up of waves. This will also set up a moderate display of sideshore winds and poor conditions for surf will change over. Expect seas to range from 2 to 4 ft. Tuesday through Saturday: The local waters are expected to be situated between high pressure to the east and an inland front Tuesday and Wednesday, which should lead to the highest period of winds and seas. In fact, Tuesday should produce solid 15 knot winds with frequent gusts to 20 knots across all local waters. The strongest winds are expected for Charleston Harbor and the Charleston County waters where there is some potential for gusts up to 25 knots. Confidence isn`t high enough to go with a Small Craft Advisory at this point, but it will need to be considered with future forecast updates. After another period of some enhanced winds Wednesday, speeds should be much lower from Thursday onward. Seas should peak in the 3-4 ft range Tuesday, then diminish back to be 2- 3 ft thereafter. Rip Currents: The presence of some swell energy and enhanced flow along the Charleston County coast will yield an elevated risk of rip currents for Tuesday. There is a Moderate Risk for the Charleston County beaches and a Low Risk elsewhere.-- End Changed Discussion --&& .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...Dennis SHORT TERM...BSH LONG TERM...BSH AVIATION...BSH/Dennis MARINE...BSH/Dennis