textproduct: Charleston

WHAT HAS CHANGED

All sections have been updated.

KEY MESSAGES

- 1) Unsettled weather will continue into late week, with increasing chances of showers and thunderstorms this weekend.

DISCUSSION

KEY MESSAGE 1: Unsettled weather will continue into late week, with increasing chances of showers and thunderstorms this weekend.

Early this morning, satellite water vapor indicated a compact mid- level disturbance off the SC coast. KCLX detected scattered to numerous showers with isolated thunderstorms across Charleston County and over the adjacent Atlantic waters. This activity should move NNE, pushing generally north of the forecast area by dawn this morning.

Recent runs of the HRRR and HREF indicate that the forecast area may remain dry through the rest of the morning. As temperatures warm to around 90 degrees by early this afternoon, a sea breeze is expected to develop. Dewpoints along and east of the sea breeze should peak in the upper 70s this afternoon. As a result, slight mixed layer instability should develop near the sea breeze as it pushes inland this afternoon. Forecast soundings indicate that PW values will remain around 2 inches, with less than 1000 J/kg of DCAPE. Given the environment of deep moisture, low shear, and instability, storms this afternoon should be efficient rain producers but likely sub-severe. HREF indicates that storms may yield swaths of rainfall exceeding an inch across inland GA/SC, with some areas potentially receiving in excess of 3 inches west of I-95. Convection is expected to dissipate by late this evening. Land areas are forecast to remain generally dry tonight, with rounds of showers and thunderstorms possible over the Atlantic.

Friday through Sunday: Upper level trough holds tight across the Ohio River Friday, as a sfc cold front dives southeastward toward the region. As noted in days past, will likely see this boundary stall overhead this weekend before it departs across the Atlantic early next week. Thus, expect an active and wet pattern to continue. Latest guidance continues to agree that scattered to numerous showers and storms will be possible, especially Friday night and Saturday. PoPs have increased as a result, with much of our area now advertising a 60-80% PoP each afternoon and evening. While there is certainly enough lift and moisture (PWATs near 2 inches) to work with, overall severe chances remain relatively low. Nonetheless, can't rule out seeing an isolated storm or so becoming strong to severe. However, think the main thing we will need to keep an eye on in the coming days is the risk of heavy rainfall, given the potential for slow moving, training, or back building storms. If these setups were to occur, could easily see locally high rainfall totals occur in a short period of time, increasing the potential for localized flooding or flash flooding, particularly in urban and low- lying areas. For now, would expect accumulations through the weekend to range between 0.5 - 1.5 inches, with isolated pockets upwards of 2 to 3 inches.

Monday Onwards: Sfc high pressure is progged to build across the Tennessee River Valley heading into the new week, allowing precipitation chances and coverage to gradually wane. As such, expect our typical summertime pattern to return, with daily chances for isolated showers and storms along/near the advancing sea breeze.

AVIATION /12Z THURSDAY THROUGH MONDAY/

Prior to the 12Z TAFs, KCLX detected land breeze near KJZI, highlighted in the TAF until 14Z. The rest of the morning should remain VFR with light SW winds. Sea breeze thunderstorms may develop near KSAV between 19-23Z, with slightly less chances at KCHS. Otherwise, TAFs will feature wind changes from SW ahead of the sea breeze turning from the SSW after the sea breeze this afternoon.

Extended Aviation Outlook: Showers and thunderstorms will bring brief flight restrictions through the weekend, especially during the afternoons.

MARINE

Today and tonight: The pressure pattern will generally support southwest winds between 10 to 15 kts across the marine zones. Wave heights are forecast to remain between 2 to 3 ft.

Friday through Monday: Sfc cold front is expected to approach the region Friday then stall overhead through the weekend. Fortunately, our waters should remain fairly calm during this time, with seas between 2 to 3 ft, and gusts averaging 15 kts or less. Thus, while Small Craft Advisories are not expected at this time, do want to highlight that some storms may result in brief periods of higher winds along with frequent lightning.

CHS WATCHES/WARNINGS/ADVISORIES

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