textproduct: Charleston

WHAT HAS CHANGED

The Aviation section has been updated for the 12Z TAFs.

KEY MESSAGES

- 1) Increasing chances for showers and thunderstorms this weekend, though no hazardous weather is anticipated at this time.

DISCUSSION

KEY MESSAGE 1: Increasing chances for showers and thunderstorms this weekend, though no hazardous weather is anticipated at this time.

Deep convection across inland GA/SC early this morning should dissipate or track north before dawn this morning. Convection during the daylight hours this morning should remain limited. High resolution guidance indicates that a weakening area of cold air damming will remain centered over the Foothills of the Carolinas, with an inverted trough across the eastern Carolinas and Georgia. Temperatures should rapidly warm into the mid to upper 80s by early this afternoon. A sea breeze should develop by late this morning, then pushing briskly inland within the inverted trough.

Given temperatures in the mid to upper 80s and dewpoints in the 70s, SBCAPE along and inland of the sea breeze may build to 2000-2500 J/kg. Deep moisture convergence should develop in the vicinity of the sea breeze, likely reaching the LFC around 850 mb. HREF indicates greater than a 30% for updraft strength greater than 30 m/s across portions of inland GA. The strong updrafts may push echo tops into the mid 40 kft, with DCAPE values between 500-800 J/kg. It is possible that one or two storms may develop localized damaging wind gusts, Severe Thunderstorm Warnings may be needed after 4 PM. In addition, Corfidi vectors indicate that the storms will track northeast around 10 kts, possibly aligned along the sea breeze. High resolution guidance indicates that storms may train along the sea breeze, or cross the sea breeze on outflow boundaries. The environment will feature PW between 1.8 to around 2 inches with a deep warm cloud layer. The 0Z HREF highlights a corridor of very heavy rainfall from Tattnall north to Allendale, with around 90% of 1 inch/3 hrs and 50% - 70% of 3 inches/3hr. Most of the rainfall will be beneficial falling within an area of Exceptional to Extreme Drought. However, rainfall rates could become locally excessive late this afternoon into early this evening. SPC highlights the risk for severe weather with a marginal risk and WPC highlights the risk for excessive rainfall with a marginal risk.

On Sunday, conditions are not expected to change much from today, with comparable temperatures and moisture content. The sea breeze will again focus the initial thunderstorms, then coverage should expand on outflow boundaries. Heavy rainfall is possible generally along and west of I-95, especially across the SC counties.

Next week, warm and moist conditions persist as the upper ridge shifts back towards the southeast United States. This is expected to bring a more summer-like pattern with diurnally driven convection each day, showers/storms forming along a sea breeze before expanding across inland areas into the early evening hours, which will continue to bring much needed rainfall to the region. Temperatures 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.

AVIATION /12Z SATURDAY THROUGH WEDNESDAY/

Prior to the 12Z TAFs: Isolated to scattered showers were tracking near the terminals. Convection is expected to remain limited through the rest of the morning, with highlight with a mention of VCSH until 17Z. As temperatures warm into the upper 80s, a progressive sea breeze and should push rapidly inland within a inverted trough across the Fall Line, winds will shift from the SE between 10-13 kts. Shower and thunderstorm coverage is forecast to become focused along the sea breeze, especially across inland GA. However, storm motions will remain light to the northeast, resulting in weakening storms to cross over the sea breeze. These storms will be highlighted with a TEMPO from 23-3Z at KSAV and PROB30 at KCHS/KJZI. Otherwise, VCSH are possible at the terminals throughout the evening hours.

Extended Aviation Outlook: TEMPO flight restrictions possible with showers and thunderstorms at CHS/JZI/SAV terminals during the afternoon hours Sunday into the middle of next week.

MARINE

Today: A sea breeze should develop by late this morning, winds will shift from the SE and increase to 10 to 15 kts. Wave heights should remain between 3 to 4 ft.

Sunday through Wednesday: Conditions are forecast to remain below Small Craft Advisory criteria into the middle of next week, with daily chances for showers and thunderstorms. High pressure to the east will drive onshore ESE flow each day, with wind speeds mostly topping out in the 10-15 knot range. Each afternoon and evening there could be some local enhancement along the land/sea interface with the diurnal sea breeze. Seas will average 2-4 feet through the period.

Rip Currents: A modest easterly swell around 3ft/9s and sea breeze influences each afternoon will keep the rip current risk in the moderate category through at least Sunday.

CHS WATCHES/WARNINGS/ADVISORIES

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