textproduct: Charleston

WHAT HAS CHANGED

The Aviation section was updated for the 12Z TAFs.

KEY MESSAGES

- 1) Increased chances for showers and thunderstorms early this week.

DISCUSSION

KEY MESSAGE 1: Increased chances for showers and thunderstorms early this week.

Early this morning, satellite water vapor indicate a large plume of moisture across the Southeast U.S. The moisture plume was positioned between a deep H5 trough centered over the Southern Plains and a 590 DM ridge centered over the western Atlantic. Water vapor and RAP40 indicates several vort maxes within the moisture plumes, tracking SW to NE along the H5 heights. These disturbances will likely trigger rounds of showers and thunderstorms across the region this morning into the daylight hours.

Using a blend of MOS, high temperatures are forecast to range in the mid to upper 80s by early this afternoon. The sfc pattern will yield light SSE winds across SE GA/SC. A sea breeze should readily develop by late this morning, then push inland this afternoon. Given temperatures well into the 80s with dewpoints in the low to mid 70s, SBCAPE should build to 1500-2000 J/kg this afternoon. As the case the past few days, a broken band of showers and thunderstorms should develop along and west of the sea breeze this afternoon. Forecast soundings indicate storm motions less than 10 mph this afternoon and evening. Give PW values around 2 inches, these slow moving storms should yield very efficient rainfall rates along and inland of the sea breeze. The 0Z HREF indicates the greatest potential for heavy rainfall should once again occur over inland GA, with a 10-30% of 3"/3hr. WPC has highlighted our inland GA counties with a marginal risk for excessive rainfall.

Tuesday: Conditions are not expected to change much from today, with comparable temperatures and moisture content. The sea breeze will again be the focus for the initial thunderstorm activity, then coverage should expand across inland areas. Locally heavy rainfall is possible generally west of I-95.

The ridge of high pressure aloft to our east restrengthens a bit on Tuesday, which will continue our warm and moist conditions across the southeast United States into the end of the week. This will also continue our daily chances for showers and thunderstorms, which will be primarily forming along an early afternoon sea breeze and then expanding inland before dissipating into the overnight hours. With PWATs remaining near 2 inches, locally heavy rainfall will remain possible. Temperatures look to remain above average, with daily highs in the upper 80s to lower 90s and overnight lows in the mid 60s to mid 70s, possibly resulting in record high minimum (warm overnight low) temperatures.

As a surface low pressure moves off the northeast coast late this week, a weak cold front is expected to push into the southeast region. Models continue to suggest this occurring Thursday into Friday, with the front lingering into the weekend before cooler air arrives as a surface high pressure slides down. The cooler temperatures look be rather refreshing, with high temperatures in the upper 70s to lower 80s.

AVIATION /12Z MONDAY THROUGH FRIDAY/

Prior to the 12Z TAFs, KCLX indicated clusters of showers developing near and over KSAV. These showers were likely responding to the passage of a mid-level disturbance. Brief rounds of showers with possible MVFR ceilings may remain across the KSAV terminal through mid-morning. Recent runs of the HRRR indicates that showers and thunderstorms will develop near a sea breeze by mid-day. Each TAF will feature a PROB30 group from 16-18Z for -TSRA. In addition, the passage of the sea breeze may result in south winds to gusts into the teens this afternoon. Winds should settle between 5-10 kts by 23Z.

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

MARINE

Today and 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 Friday: Conditions are forecast to remain below Small Craft Advisory criteria into the end of the week, with daily chances for showers and thunderstorms. High pressure to the east will drive onshore ESE flow on Tuesday, though the surface high pressure slides a little closer on Wednesday causing winds to shift to become out of the WSW, though still remaining well below small craft criteria. Thursday and Friday will see a stalled front near the area, keeping winds on the weaker side.

Rip Currents: A modest easterly swell around 3ft/8s and sea breeze influences each afternoon will keep the rip current risk in the moderate category at all area beaches through Tuesday.

CHS WATCHES/WARNINGS/ADVISORIES

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