textproduct: Charleston

WHAT HAS CHANGED

The Aviation section has been updated for the 00z TAF issuance.

KEY MESSAGES

- 1) Periods of showers and thunderstorms this week through the weekend could bring locally heavy rainfall. The threat for organized severe weather is low at this time.

DISCUSSION

KEY MESSAGE 1: Periods of showers and thunderstorms this week through the weekend could bring locally heavy rainfall. The threat for organized severe weather is low at this time.

The region will remain on the western periphery of high pressure at the surface and aloft through tonight. The atmosphere remains quite moist with PWats near or just over 2 inches, which is above the 95th percentile of climo. Afternoon convection has steadily shifted inland into the evening, leaving most of the forecast area free of showers and storms currently. Overnight, the environment remains quite moist though there are no features to speak of. Model guidance does not generate much nocturnal activity, though isolated to scattered showers and storms could develop at any time across the area. There is some fog potential across the far interior where the heaviest rain fell today.

This general trend will continue daily through Thursday. Again, some storms could produce heavy downpours and minor flooding issues, but much of the rainfall will help ease ongoing dry conditions.

Rain chances will increase Friday through the weekend as a weak front meanders in the vicinity, bringing a more widespread pattern of showers and thunderstorms. Moisture convergence along the front will increase PWATS to around 2.0 - 2.2 inches Friday and through the weekend. Several rounds of rainfall which could be heavy at times, could lead to localized minor flooding, especially in areas that see repeated storms. Current forecast guidance suggests widespread rainfall totals through the weekend around 2 to 4 inches. The NBM currently shows a 20-35% probability of 3 inches of rain or greater falling over a 72-hour period between Friday morning and Monday morning, with the highest chances located along the coast. While confidence is increasing in a wetter pattern later this week and weekend, details on exact rainfall totals and where the heaviest rain sets up will likely change over the coming days.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

The 00z TAF period begins with VFR conditions at KCHS, KJZI, and KSAV. Overall, model guidance would suggest that VFR is the most likely condition through the overnight, though there are some hints that MVFR ceilings could develop inland late tonight. These MVFR ceilings would have the best chance to reach KSAV, but we have kept the forecast VFR for now. There could also be a short period of MVFR ceilings just after sunrise when diurnal cumulus and stratocumulus develops with the onset of surface heating. Regarding shower and thunderstorm chances late in the TAF period, the best coverage is expected inland of the TAF sites. The best chance for brief impacts would be from late morning through early afternoon before activity steadily shifts inland.

Extended Aviation Outlook: TEMPO flight restrictions possible with showers and thunderstorms at CHS/JZI/SAV terminals mainly during the afternoon hours through the week. In addition, patchy overnight fog and/or stratus cannot be ruled out after recent rains.

MARINE

Through tonight: High pressure centered over the western Atlantic will remain remain over the marine zones. As a result, winds will generally remain from the SSE through the period, favoring speeds between 10 to 15 kts. Wave heights are expected to range between 3 to 5 ft.

Tuesday through Saturday: Generally no marine concerns as conditions are forecast to remain below Small Craft Advisory criteria through the end of the week, with daily chances for showers and thunderstorms.

Rip Currents: An elevated rip current risk will remain through the week with a modest easterly swell around 3 to 4 feet every 7 seconds and sea breeze influences. A moderate risk of rip currents is in place for all area beaches through at least Wednesday.

CHS WATCHES/WARNINGS/ADVISORIES

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