textproduct: Charleston

WHAT HAS CHANGED

All sections have been updated.

KEY MESSAGES

- 1) Typical summertime storm activity will continue through early this week.

- 2) Hot and humid conditions will return this week.

DISCUSSION

KEY MESSAGE 1: Typical summertime storm activity will continue through early this week.

Today, high pressure centered near Bermuda will gradually ridge to the west over the region. Forecast soundings indicate that mixing up to around 5 kft should keep sfc dewpoints in the mid 70s inland, keeping LFC above 6 kft. A sea breeze may not develop until early this afternoon, following light west winds through this morning. As the sea breeze advances inland, isolated to scattered thunderstorms may develop. However, as a H5 ridge gradually builds across FL, shallow lapse rates may remain across the forecast area this afternoon. These thunderstorms should remain as general thunderstorms with limited updraft strength. In addition, rainfall potential will remain limited by the short lifespan of these pulse thunderstorms.

Monday, the overall pattern changes very little from today. Isolated to scattered thunderstorms should develop during the afternoon and evening. However, forecast soundings do indicate a bit more moisture and potentially greater instability. However, the potential for any thunderstorm impacts appears limited by rising H5 heights across the region.

Tuesday through Thursday, the main issue will be the heat wave across the region. The hot and humid air mass may result in moderate instability during the afternoon and evening. Forecast soundings feature high LFC with an inverted-V profile, DCAPE values may peak in some areas between 1000-1500 J/kg. It is interesting to note that some AI Convective Hazard Forecast products indicate a 15-30% chance for severe thunderstorms on Tuesday.

KEY MESSAGE 2: Hot and humid conditions will return this week.

Temperatures for today will be right around average for early/mid August, largely in the lower 90s though a few locations may get up into the mid 90s. With dewpoints in the mid to upper 70s, heat index values will peak in the 100-105 deg F range this afternoon. Temperatures rise into Monday as a weak coastal trough begins to develop, advecting in slightly warmer temperatures from the southwest/west, with this pattern expected to linger across the region throughout the workweek.

High temperatures each day are expected to peak in the lower to mid 90s, with chances for upper 90s by the end of the week. Inland areas (especially those well west of the I-95 corridor) will likely see enough surface mixing to limit dew points to the mid 70s, while those along the coast will likely see dew points linger in the upper 70s to lower 80s. Combined with the aforementioned temperatures in the mid to upper 90s, will likely see some heat index values in the 105-112 range along the coast on Monday through Wednesday. By the end of the week, upper level ridging looks to further increase temperatures, bringing heat index values up to 115 deg F for isolated areas. Heat Advisories will likely be needed next week, with Extreme Heat Warnings not out of the question. Current forecast is within a few degrees of daily record highs and record high minimum Tuesday through Friday, for more see the climate section below.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

6Z TAFs: It is possible that some brief fog could develop across KJZI and KSAV during the pre-dawn hours this morning, give wet ground and calm winds. We will leave out of the TAFs at this time and monitor observations. Light west winds should develop after sunrise and remain until the sea breeze develops by 19z. This afternoon, in the wake of the sea breeze, winds should turn from the south and pick up to near 10 kts. The coverage of convection appears limited, TAFs will remain dry at this time.

Extended Aviation Outlook: Periodic flight restrictions are expected in showers and thunderstorms through next week.

MARINE

The pressure pattern will support south winds between 10 to 15 kts today, shifting from the southwest tonight. Wave heights are forecast to remain between 2 to 3 ft.

Monday through Thursday: Atlantic high pressure will be the dominant synoptic feature into next week, keeping winds out of the south- southwest. Light to moderate winds prevail on Monday, though gusty winds are expected along the land/sea interface during the afternoon hours as the sea breeze moves ashore. Coastal troughing sets up overnight into Tuesday and continues throughout the week, keeping winds breezy with gusts into the teens to lower 20s. Seas look to remain largely in the 2-3 ft range, though 4 foot waves will be possible at times in the South Carolina waters from 20-60nm offshore. Small Craft Advisories currently look unlikely, but will be something to monitor.

Coastal Flooding: While elevated tidal cycles are expected next week due to the upcoming perigee and new moon, the south-southwesterly surface flow should keep tidal departures low, limiting the overall coastal flood threat.

CLIMATE

Record High Temperatures:

August 11: KCHS: 98/1968 KCXM: 97/1954 KSAV: 100/2011

August 12: KCHS: 98/1957 KCXM: 98/1998 KSAV: 100/1999

August 13: KCHS: 100/1995 KCXM: 98/1913 KSAV: 98/2010

Record High Minimum Temperatures:

August 10: KCHS: 80/2007 KCXM: 83/2007 KSAV: 79/2024

August 11: KCHS: 79/1983 KCXM: 82/2021 KSAV: 78/1878

August 12: KCHS: 79/1999 KCXM: 83/2021 KSAV: 80/1878

August 13: KCHS: 81/2023 KCXM: 83/2023 KSAV: 81/2023

August 14: KCHS: 80/2023 KCXM: 83/2023 KSAV: 80/2023

CHS WATCHES/WARNINGS/ADVISORIES

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