textproduct: Charleston

WHAT HAS CHANGED

All sections have been updated.

KEY MESSAGES

- 1) Strong to severe thunderstorms are possible this evening.

- 2) Unsettled weather is expected from Wednesday into the weekend, with daily chances for showers and thunderstorms and the potential for locally heavy rainfall.

DISCUSSION

KEY MESSAGE 1: Strong to severe thunderstorms are possible this evening.

Moisture will continue to steadily increase this (Tuesday) evening, while a stationary front remains draped over the Southeast. Best chances for storms looks to be across Georgia and the southeast South Carolina coast during the late afternoon and early evening hours. However, some remnant drier air in subsidence could aide to keep storms more isolated to scattered closer to Charleston and the Tri-county area. MLCAPE values are expected to climb to around 2000-2500 J/kg across the area which is a tick lower than the past few days. With rather deep moist profiles, today should feel more like a standard summer afternoon as storms will likely need to cluster and have a few boundary collisions to become strong/severe. However, like most summer afternoons we do expect at least a couple clusters to develop and a few strong to severe wind gusts cannot be ruled out. The greatest threat appears to be across interior southeast Georgia. Also, PWATS are expected to increase from 1.7 to 2.0 inches over the next several hours, which would be enough to support rather heavy rain rates within the strongest storms. If any storms are able to linger across the metro areas, then flooding concerns could arise.

KEY MESSAGE 2: Unsettled weather is expected from Wednesday into the weekend, with daily chances for showers and thunderstorms and the potential for locally heavy rainfall.

An upper-level trough will remain positioned across the Ohio River Valley with a series of shortwaves moving through the region through the end of the week. At the surface, a stationary front will linger across the Southeast before a cold front approaches this weekend. This pattern will provide repeated sources of lift, while abundant atmospheric moisture, with PWAT values near or slightly above 2 inches, well above normal for late August, will support efficient rainfall production. As a result, showers and thunderstorms will be possible each day, with most guidance suggesting convection will be scattered to numerous in coverage. However, confidence in the exact location and timing of storms remains relatively low.

An isolated storm could become strong to severe, with damaging wind gusts possible. The primary concern, however, will be locally heavy rainfall. The stationary front draped over the area could result in slow-moving storms or repeatedly track over the same areas. These processes can produce locally high rainfall totals in a short period of time, increasing the potential for localized flooding or flash flooding, particularly in urban and low-lying areas.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

25/18z TAF Discussion: Showers and thunderstorms will develop mainly along the slow-moving sea breeze this afternoon and evening. Confidence in thunderstorms directly impacting the terminals is highest at KSAV, with lower confidence at KJZI and KCHS. As a result, a TEMPO group was maintained at KSAV. Thunderstorms are expected to diminish this evening, with prevailing VFR conditions anticipated through the overnight hours.

Extended Aviation Outlook: Daily chances for showers and thunderstorms will continue through the weekend, with storms potentially producing temporary flight restrictions, reduced visibility, gusty winds, and brief periods of heavier rainfall each afternoon.

MARINE

Through Tonight: Easterly winds during the late afternoon will shift southerly later this evening. Wave heights are forecast to remain between 2 to 3 ft.

Wednesday through Sunday: South/southwesterly winds will continue through the period, with winds averaging 15 knots or less. Small Craft Advisories are not expected during the period at this time. However, any showers or thunderstorms that develop over or move across the waters could produce locally strong wind gusts, frequent lightning, and/or briefly higher seas.

CHS WATCHES/WARNINGS/ADVISORIES

GA...None. SC...None. MARINE...None.