textproduct: Charleston

WHAT HAS CHANGED

All sections have been updated.

KEY MESSAGES

- 1) Typical summertime storm activity will continue through mid-week. Some storms may produce strong to severe wind gusts.

- 2) Hot and humid conditions will return Tuesday and persist into the weekend. Heat Advisories will likely be required and Extreme Heat Watches/Warnings cannot be ruled out, especially towards the end of the week.

DISCUSSION

KEY MESSAGE 1: Typical summertime storm activity will continue through mid-week. Some storms may produce strong to severe wind gusts.

Today, the axis of 596DM H5 ridge will settle over central FL this afternoon. Near term guidance indicate that weak vort maxes may track across the SC Lowcountry this afternoon. At the sfc, recent runs of the HRRR indicates that the sea breeze will begin to push inland during the early afternoon. By the time the sea breeze forms, temperatures across the forecast area are expected to peak in the mid 90s with dewpoints in the mid to upper 70s. SBCAPE may range between 2000-2500 J/kg, possibly higher in the vicinity of the sea breeze. In addition, forecast soundings indicate that DCAPE values may exceed 1000 J/kg. Isolated to scattered thunderstorms are forecast to develop between the weak mid-level disturbance and the sea breeze, late this afternoon into early this evening. HREF updraft strength probabilities increase to 10-30% of 30 m/s over Berkeley and Dorchester Counties. It is possible a collapsing water-loaded updraft could yield a damaging wind gusts late this afternoon into early this evening.

Tuesday: A sfc trough should develop across the central Carolinas into GA. Guidance seems to shows an old MCV sourced from northern GA convection reaching SE GA during the afternoon. However, the sfc trough to the west should draw the sea breeze inland a bit earlier than today. PoPs will be increased across along and south of the Savannah River, and adjacent waters for Tuesday afternoon. Given moderate instability and decent DCAPE, it is possible that one or two of these storms could become severe.

Wednesday and 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. AI Convective Hazard Forecast products indicate a 15-30% chance for damaging wind gusts across inland SC/GA counties on Wednesday. Deep mixing and ridging aloft may suppress thunderstorm activity for many areas on Thursday.

KEY MESSAGE 2: Hot and humid conditions will return Tuesday and persist into the weekend. Heat Advisories will likely be required and Extreme Heat Watches/Warnings cannot be ruled out, especially towards the end of the week.

Heat headlines are likely Tuesday and into the weekend as heat index values soar into the 100-110 range each afternoon through mid-week and upwards of 115 late in the week. The daily record highs and record high minimum temperatures will likely be challenged at our three climate sites (see Climate Section for more details). Given the very mild overnight periods and minimal coverage of precipitation, there will be few instances of relief from the heat this week and into the weekend.

Monday through Wednesday: As ridging aloft builds into the region on Monday temperatures will reach into the low 90s across most locations. Combined with dew points in the mid 70s heat index values will likely reach into the 100-105 range this afternoon, warmest along the coast. Heat Advisories have not been issued for Monday, however a few locations may see a brief moment of heat index values around 108 in the afternoon hours. Tuesday and Wednesday will see increasing high temperatures, with highs warming into the mid 90s by mid week. The combination of these temperatures with dew points in the mid 70s will yield heat index values in the 105-110 range. Heat Advisories are likely for portions of the forecast area each afternoon, especially east of I-95 where the sea breeze will bring higher dew point values.

Thursday and Friday: The ridging aloft amplifies towards the end of the week, likely bringing the warmest temperatures of the heat wave. Highs on each day will likely reach into the upper 90s, with a brief moment of touching 100 not out of the question. Heat index values west of I-95 will likely reach 105-108 (Heat Advisory) with locations east of I-95 reaching heat index values as high as 115. Extreme Heat Watches/Warnings may be required for these locations.

AVIATION /06Z MONDAY THROUGH FRIDAY/

6Z TAFs: At the sfc, recent runs of the HRRR indicates that the sea breeze will begin to push inland during the early afternoon. Light winds from the WSW are forecast before the sea breeze, shifting from the SW in the wake of the sea breeze. Isolated to scattered thunderstorms are forecast to develop between a weak mid-level disturbance and the sea breeze, late this afternoon into early this evening. The KCHS TAF will feature a TEMPO from 20-24Z for -TSRA. Winds should decrease to around 5 kts by mid-evening.

Extended Aviation Outlook: Prevailing VFR.

MARINE

The pressure pattern will support south winds between 15 to 20 kts today, shifting from the southwest tonight. Wave heights are forecast to remain between 2 to 3 ft.

Tuesday through Friday: Conditions are expected to remain below Small Craft Advisory criteria this week. A weak coastal trough will set up across the marine waters this week, persisting into the start of the weekend. This set up will keep conditions across the marine waters breezy with southwesterly winds gusting around 15 to 20 knots. 2 to 3 ft seas are expected across the marine zones this week.

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

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

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

August 14: KCHS: 102/1995 KSAV: 102/1925

August 15: KCHS: 96/2023 KSAV: 100/1918

Record High Minimum Temperatures:

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

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

August 12: KCHS: 79/1999 KSAV: 80/1878

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

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

August 15: KCHS: 78/1995 KCXM: 83/2021 KSAV: 80/1995

August 16: KCHS: 78/2019 KSAV: 78/2019

CHS WATCHES/WARNINGS/ADVISORIES

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