textproduct: Charleston

WHAT HAS CHANGED

Updated the Key Messages, and the Aviation section to reflect the 18Z TAFs.

KEY MESSAGES

- 1) Unseasonably warm temperatures continue through Wednesday.

- 2) Showers and thunderstorms likely Thursday as a cold front moves through.

DISCUSSION

KEY MESSAGE 1: Unseasonably warm temperatures continue through Wednesday.

An amplifying ridge aloft will shift over the Southeast coast late Tuesday night, allowing heights to rise and temperatures to warm further. Overnight lows tonight will only dip into the lower to middle 60s. Wednesday is expected to be the warmest day of the week with highs in the middle to upper 80s away from the beaches. Some locations across interior Southeast Georgia could tap into the lower 90s. Most locations will see afternoon highs around 15-20 degrees above normal for mid-March. Record highs and/or record high minimum temperatures could be exceeded at KCHS, KSAV, and KCXM (see Climate section below).

KEY MESSAGE 2: Showers and thunderstorms likely Thursday as a cold front moves through.

Upper level flow will shift on Thursday as a trough and surface cold front move east from the Tennessee River Valley toward the Atlantic. South to southwest flow ahead of the front will support increasing moisture across the region. Combined with unseasonably warm temperatures, this should provide enough instability for numerous showers and thunderstorms to develop ahead of the advancing front. Models indicate a broken line of convection moving across the forecast area late morning into the afternoon. With FROPA currently expected late Thursday afternoon, instability should remain somewhat limited with SBCAPE values peaking below 900 J/kg. However, strong deep-layer shear (6070 kt) will be present, so an isolated strong thunderstorm cannot be ruled out. If the front slows and delays storms into the evening hours, slightly greater instability could develop, increasing the potential for a few strong to marginally severe storms.

Rainfall amounts of around one-quarter to three-quarters of an inch are expected. Flooding is not anticipated given the progressive nature of the system. Outside of thunderstorms, Thursday will be breezy with gusts around 20-25 mph over land. Gusts over Lake Moultrie could occasionally approach advisory levels, though probabilities for 25 kt gusts remain too low for a Lake Wind Advisory at this time.

Temperatures will drop noticeably behind the front as cold air advection develops Thursday afternoon, with the most significant cooling occurring Thursday night. Overnight lows will fall roughly 20 degrees compared to previous nights, dropping into the low to mid 40s away from the beaches. A much cooler day is expected Friday, with highs in the upper 60s to lower 70s. Temperatures then rebound into the 70s and 80s over the weekend.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

18Z TAFs: VFR.

Extended Aviation Outlook: Flight restrictions due to low stratus/fog remain possible through Wednesday. A brief period of showers and thunderstorms Thursday afternoon ahead of a cold front could result in short-lived flight restrictions and gusty winds.

MARINE

Tonight: High pressure in the western Atlantic will yield S to SSW winds around 10 kt this evening, becoming SW 10-15 kt after midnight. Seas will average 2-3 ft within 20 nm and 3-4 ft for the GA waters beyond 20 nm.

Wednesday through Sunday: High pressure will dominate before a cold front approaches from the west late Wednesday, causing winds and seas to increase. Small Craft Advisories will likely be needed for most marine zones where gusts are anticipated to reach 25-30 kt Wednesday night. Building seas will follow, peaking around 5-8 ft Thursday night. The cold front should cross the waters late Thursday afternoon, causing winds to veer out of the northeast in its wake. Gusts to gale force for a few hours are possible across the Charleston County nearshore waters (0-20 nm) and the Georgia offshore waters from 20-60 nm Thursday night and a brief Gale Watch/Warning could be needed. Conditions will improve Friday and into the weekend as high pressure builds in the wake of the front.

CLIMATE

Record High Temperatures:

March 11: KCHS: 85/2015 KCXM: 82/1997 KSAV: 87/2015

Record High Minimum Temperatures:

March 10: KCHS: 64/1974 KCXM: 65/1974 KSAV: 63/1909

March 11: KCHS: 63/2015 KCXM: 64/2016 KSAV: 64/1974

EQUIPMENT

The KCLX radar is scheduled for radome panel replacement March 14-16, 2026. The radar will be down during this time. Users are encouraged to use data from the following nearby radar sites during the maintenance outage:

KCAE - Columbia, SC KLTX - Wilmington, NC KJAX - Jacksonville, FL KVAX - Moody AFB, GA KJGX - Robbins AFB, GA

CHS WATCHES/WARNINGS/ADVISORIES

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