Marine Weather and Tide Forecast for Port Royal, SC

KEY MESSAGES
- 1) Showers and thunderstorms anticipated late afternoon into early evening. A few stronger thunderstorms possible with gusty winds.

- 2) Unseasonably warm temperatures continue through Wednesday, along with increased rain chances.

- 3) A cold front may bring widespread rainfall on Thursday in addition to breezy conditions.

DISCUSSION
KEY MESSAGE 1: Showers and thunderstorms anticipated late afternoon into early evening. A few stronger thunderstorms possible with gusty winds.

A dampening h5 shortwave moving across the Ohio River Valley will help drive a cold front into the Southeast United states this afternoon. The front is forecast to steadily weaken and stall to the west and north late day and overnight, allowing convection to outrun strongest forcing while approaching Southeast South Carolina and Southeast Georgia mid-late afternoon. Latest radar trends show convection upstream, mainly in the form of light to moderate showers cross Central Georgia. Activity should remain in a rather weakened state approaching the local area early afternoon, but could slowly show signs of gradual strengthening while traversing the local area from west to east mid-late afternoon into early evening given stronger instability associated with sfc temps in the low/mid 80s and increasing moisture supply within a south/southwesterly flow. An axis of SBCAPE around 2000-3000 J/kg along with 0-6 km Bulk Shear in the 25-30 kt range could support some organization to convection, with the potential for a few stronger thunderstorms across the Tri-County Area near the southern extent of a "Marginal Risk" depicted on the Day 1 SPC Severe Weather Outlook. Mid-lvl lapse rates are poor, but low-lvl lapse rates between 7-8 C/km and mostly unidirectional wind profiles suggest a wind threat with stronger thunderstorms.
A marginally severe thunderstorm can not be ruled out late afternoon/early evening with damaging winds, especially if activity can develop across the local area prior to the bulk of convection upstream, but the risk for strong/severe thunderstorms should diminish with diurnal heat loss (instability) by mid evening.

Outside of convection, above normal temperatures will continue with highs poised to reach into the lower-mid 80s away from the beaches.
The record high of 86 at KSAV set in 1974 could be challenged. It will remain warm overnight with lows only dropping into the lower 60s.

KEY MESSAGE 2: Unseasonably warm temperatures continue through Wednesday, along with increased rain chances.

The mid-levels will consist of zonal flow overhead Monday. Ridging builds over the Deep South Tuesday, then shifts over the Southeast U.S. on Wednesday. At the surface, a stalling/dissipating front will be to our northwest on Monday, while High pressure is in the western Atlantic. The High will prevail in this location through Wednesday.
This pattern will usher moisture into our area through the middle of next week. NBM POPs should be slight chance late Monday, then increasing to chance POPs Tuesday. Any showers/thunderstorms during this time period are expected to be fast moving, leading to low rainfall amounts. No severe weather is expected.

Unseasonably warm temperatures will continue through Wednesday.
Highs will range from near 80 degrees to the upper 80s, except cooler temperatures along/near the coast. Wednesday should be the hottest day across our entire area with a few spots across our interior GA counties making a run for the 90 degree mark. Lows each night will generally be in the upper 50s to lower 60s.

KEY MESSAGE 3: A cold front may bring widespread rainfall on Thursday in addition to breezy conditions.

The mid-levels will consist of a trough quickly moving over the East Coast early Thursday, then offshore from the late afternoon into the overnight hours. At the surface, a cold front, will quickly move from west to east through our area, during the morning or afternoon, shifting offshore during the evening and overnight hours. There will be a deep plume of moisture ahead of this front. The combination of the moisture and lift may generate widespread showers across our area. Though, due to the fast movement, rainfall amounts look to remain on the lighter side at under 0.5". Given the unseasonably warm temperatures ahead of the front, there should be just enough instability to fire off some thunderstorms. But the risk of severe weather is low given the unfavorable (early) timing of the front.
Additionally, expect breezy southerly winds ahead of the front.
Winds will clock around to the west/northwest behind it and increase due to cold air advection and building strong High pressure.

The High will bring dry conditions for the end of the week. High temperatures will be a few degrees above normal on Friday, then well above normal on Saturday.

AVIATION /18Z SUNDAY THROUGH FRIDAY/
VFR conditions should prevail at CHS/JZI/SAV terminals through late afternoon hours, but increasing chances of showers and thunderstorms should bring TEMPO MVFR conditions during the 22Z Sunday to 04Z Monday timeframe. Once shower/thunderstorm activity pushes offshore this evening, the risk for IFR cigs arrives at CHS/JZI, primarily around 06-14Z Monday. MVFR cigs arrive at SAV during the same timeframe, although TEMPO IFR cigs are possible as well. VFR conditions arrive at all terminals mid-late Monday morning (14-15Z), then should prevail through 18Z Monday.

Extended Aviation Outlook: Flight restrictions are possible each night and morning through midweek due to low stratus/fog. Brief flight restrictions are possible due to showers and thunderstorms on Tuesday. A cold front should bring flight restrictions and breezy conditions on Thursday.

MARINE
Today and Tonight: Latest webcams and vis sat indicated patchy dense fog across local waters near Kiawah, IOP and Folly Beach, SC. Fog could linger into late day/early evening hours prior to shower and thunderstorm activity shifting offshore this evening.
Otherwise, southerly winds will generally range between 10-15 kt through the period. Some gusts to 20 kt are possible across nearshore SC waters as well. Seas will remain in the 2-4 ft range nearshore and up to 4-5 ft across offshore Georgia waters.

Extended Marine: High pressure will be the dominant weather feature across our local waters through the middle of this week. Expect south/southwest wind sustained in the 5-10 kt range and seas 2-4 ft. A cold front will approach from the west late Wednesday, causing winds and seas to increase to Small Craft Advisory levels across all of our ocean zones. The cold front should cross through our waters Thursday, causing winds to veer behind it and further increase. Gusts to gale force are possible across portions of our waters Thursday and Thursday night. High pressure building into the region will lead to improving conditions for the end of the week.

CLIMATE
Record High Temperatures:

March 8: KCHS: 86/1974 KCXM: 86/1951 KSAV: 86/1974

March 9: KCHS: 87/1974 KCXM: 84/1974 KSAV: 88/1974

March 10: KCHS: 90/1974 KCXM: 87/1974 KSAV: 91/1974

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

Record High Minimum Temperatures:

March 8: KCHS: 63/2022 KCXM: 65/2022 KSAV: 65/1880

March 9: KCHS: 66/2022 KCXM: 65/2022 KSAV: 65/2022

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

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

March 12: KCHS: 62/1985 KCXM: 64/1973 KSAV: 65/1973

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.