textproduct: Charleston

WHAT HAS CHANGED

All sections and Key Messages have been updated.

KEY MESSAGES

- 1) Risk for low clouds and fog this morning with rain chances increasing this afternoon into tonight. Above normal temperatures continue.

- 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: Risk for low clouds and fog this morning with rain chances increasing this afternoon into tonight. Above normal temperatures continue.

A warm and moist airmass remains in place this morning with the center of subtropical high pressure still centered well offshore of the Southeast U.S. coast. Southerly breezes are a bit stronger than last night at this time with the gradient beginning to tighten between the high and an approaching cold front. Stratus is expected to slowly expand with time, but the increasing southerly flow should limit its build-down potential. Some degree of sea fog will likely impact the coastal counties through sunrise, but it remains unclear how widespread or impactful any sea fog will be given the various global and near-term, high-res models are not initializing the fog/stratus situation well. With winds expected to gradually veer with time, the risk for dense fog with visibilities 1/4 mile or less should mainly remain confined to the beaches and barrier islands, possibly reaching as far inland as the US-17 corridor in southern South Carolina, including parts of the Charleston Metro Area. While it is still possible a Dense Fog Advisory may eventually be needed for some areas through daybreak, the extent of the dense fog should not be nearly was it was Saturday morning.

A dampening shortwave moving across the Ohio Valley will help drive a weakening cold front into the Southeast U.S. today. The front is forecast to steadily weaken and eventually stall to the north and west overnight as the supporting shortwave shears out to the northeast and the frontal remnants become increasing parallel to the flow aloft. Still, several bands of showers/tstms are expected to develop within the warm sector later today (possibly including some sea breeze induced activity), being supported by a lingering secondary shortwave that will cross the southern Appalachians/Deep South late this afternoon and from the right entrance region of the jet streak exiting the Mid-Atlantic states. Expect a few tstms to occur with sufficient moisture and instability in place. 08/01z NBM pops of 40-60% look reasonable and were maintained. Rain chances will gradually end from west-end overnight.

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.

Upper level ridging has led to impressive geopotential heights peaking at or above the 90th percentile wrt to climatology over the coming days, as the latest ensemble situational awareness tables continue to show, and will continue our well above normal temperatures into the new work-week. There will be a couple chances for light scattered showers, possibly including an isolated embedded thunderstorms at times, first Monday afternoon into the evening as a weak shortwave passes overhead, leading to temperatures "only" reaching into the lower to mid 80s. Another shortwave takes aim and moves through early Tuesday into the afternoon hours, bringing with it another chance for light rainfall. Severe weather is not currently expected on either day.

The warmest/hottest day is expected for Wednesday as the geopotential heights peak and chances for rainfall are lowest, with the 1Z NBM having a max temperatures grid of 90 degrees for a small portion of southeast Georgia. NBMV5 probabilities for reaching/exceeding 90 degrees are 40-50% across southeast Georgia, with additional support from the ECMWF EFI showing unusually warm weather is expected for the region. The latest forecast ties the record warm low temperature at Savannah on Tuesday, and is within 3 degrees of record highs and record warm lows through Wednesday.

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

A strong upper level trough lifts towards the east coast on Thursday, pushing a strong cold front through the region. The timing of this cold front remains the main question, though the 07.18Z model suites have been narrowing the time window down to early to late morning hours. Scattered showers and thunderstorms out ahead of and then behind the front are expected to bring widespread rainfall to the region, though due to the progressive nature rainfall amounts look to remain on the lighter side at under half an inch. Severe weather looks unlikely given the unfavorable timing of the front, with models indicating the instability is well out ahead of the front over the Atlantic by the time the front rolls through.

Breezy winds out of the south will develop ahead of the front as the surface pressure gradient increases Wednesday, with winds increasing behind the front on Thursday as cold air advection ahead of a strong surface high pressure takes place. Max temperatures on Thursday look to hold onto at least normal temperatures before the cooler air moves in, with Friday looking to have max temperatures in the mid 60s to lower 70s...still above normal for majority of the area.

Warm temperatures build back into the region for the weekend as zonal flow sets up with the region on the southern periphery of the polar jet.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

08/06z TAF Discussion: KCHS/KJZI: The risk for stratus and IFR cigs are expected to increase in the 08-09z window, although confidence is only moderate at this time. There should be enough southerly flow to prevent significant fog formation at KCHS, but some sea fog could lower vsbys at KJZI at times. Temporary conditions were limited just below alternate minimums at KJZI to account for this. VFR should return shortly after daybreak and continue through the remainder of the 06z TAF period. Risk for showers/tstms will increase after 00z. VCSH was introduced to trend for now.

KSAV: Satellite showed stratus just west of the terminal at TAF issuance times. IFR cigs are expected to build into the terminal shortly and persist through daybreak. Southerly flow looks strong enough to preclude fog development, except briefly just before daybreak. VFR should return shortly after daybreak and continue through the remainder of the 06z TAF period. Risk for showers/tstms will increase after 00z. VCSH was introduced to trend for now.

Extended Aviation Outlook: Restrictive ceilings and visibilities are possible overnight into the early morning hours each night into the middle of the week due to low stratus/fog. Additional chances for scattered showers and thunderstorms return Monday afternoon/evening and again Tuesday, leading to chances for temporary flight restrictions.

MARINE

Through Tonight: A risk for sea fog persists, but it remains unclear how widespread it will become prior to daybreak. Webcams have highlighted patchy sea fog moving onshore at Tybee at times, but the satellite presentation is less than great. Patchy to areas of fog were highlighted for now, but a Marine Dense Fog Advisory may be needed at any point. The risk for some degree of sea fog will linger into tonight. Otherwise, winds will veer to the south and southwest later this morning and increase to 10-15 kt. These will linger into tonight. Seas will remain in the 2-4 ft range nearshore and as high as 4-5 ft over the Georgia offshore waters.

Monday through Thursday: High pressure will remain the dominant weather feature across local waters into next week, favoring a south/southeast wind in the 10-15 kt range and seas generally between 2-4 ft. Surface winds will become more south/southwest, but will continue to remain well below Small Craft Advisory levels between Atlantic high pressure and a stalling/dissipating front well inland. As that front continues to push eastwards, the pressure gradient rises and may result in winds reaching Small Craft Advisory levels late Wednesday into Thursday ahead of the front, with renewed gusty conditions behind the front where gale force gusts cannot be ruled out at this time into Friday. In addition to the gusty winds, 6-8 foot seas build into the region 10+NM out to sea Thursday into Friday morning.

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.