textproduct: Charleston

WHAT HAS CHANGED

The Aviation Section has been updated for the 12Z TAF issuance.

KEY MESSAGES

- 1) A cold front will bring an increased risk for showers and thunderstorms to the region Thursday into Saturday.

DISCUSSION

KEY MESSAGE 1: A cold front will bring an increased risk for showers and thunderstorms to the region Thursday into Saturday.

High pressure across the Atlantic will favor a light southerly flow across the Southeast United States in advance of an approaching cold front driven by a mid-lvl trough advancing across the Great Lakes/Ohio River Valley mid-week. Deep moisture (PWATs ~2.0 inches) is expected to advect across the local area on Thursday while warm conditions persist prior to the front arriving, but increasing cloud cover should limit instability when modest levels of shear associated with enhanced low-lvl wind fields arrive/develop across the Southeast Unites States while a strong h25 jet core passes inland and to the north.

Timing of the front remains the most substantial uncertainty in regards to shower and thunderstorm arrival/coverage as well as the progression of the mid-upper lvl trough north of the region Thursday. Guidance remains rather split with cold fropa occurring between the Thursday evening through Friday morning time range, with the GFS remaining the faster and more progressive solution along with dry high pressure occurring later Friday into Saturday, while the ECMWF suggests a more stalling out of the front just south of the region as the mid-upper trough and sfc front become much more displaced from each other. The later solution would result in precip activity holding across the local area through Friday and possibly through much of the day on Saturday, but rainfall totals and the risk for flooding (low) remain relatively similar under either scenario. Regardless of the the outcome, the environment supports at least scattered shower and thunderstorm activity Thursday and Friday as the front approaches and shifts across the region. Stronger thunderstorm chances remain low given fropa is likely to occur during overnight hours, but can't be ruled out if activity is able to maintain some organization while entering inland areas Thursday afternoon into early evening hours.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

VFR conditions will prevail at CHS/JZI/SAV terminals through 12Z Wednesday. However, gusty south/southeast winds around 20 kt are anticipated at all terminals this afternoon.

Extended Aviation Outlook: Flight restrictions from showers and thunderstorms are possible Thursday and Friday as a cold front moves through the region.

MARINE

Southerly flow will strengthen ahead of an approaching cold front Thursday. There could be period of 25 kt winds and 6 ft seas over portions of the Charleston nearshore waters Thursday afternoon/evening. Small Craft Advisories may be needed.

CHS WATCHES/WARNINGS/ADVISORIES

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