textproduct: Charleston

WHAT HAS CHANGED

All sections have been updated.

KEY MESSAGES

- 1) Hot and humid conditions across southeast Georgia and the South Carolina Lowcountry this afternoon. A couple of strong to severe thunderstorms are possible near the sea breeze this afternoon into early this evening.

- 2) Hot and humid conditions will persist through much of the week.

- 3) Typical summertime convection returns this week.

DISCUSSION

KEY MESSAGE 1: Hot and humid conditions across southeast Georgia and the South Carolina Lowcountry this afternoon. A couple of strong to severe thunderstorms are possible near the sea breeze this afternoon into early this evening.

Monday: KCLX has detected periodic isolated showers and thunderstorms across SE GA this morning. SCHC PoPs were added to the forecast through the pre-dawn hours. This convection was likely responding to a weak impulse with the SW/NE flow east of a H5 trough. Weak disturbance may continue to track across the forecast area through this afternoon/evening. Hot and humid conditions across the region may yield SBCAPE between 2000-2500 J/kg, especially after the sea breeze develops. Scattered thunderstorms should develop this afternoon, triggered by passing weak mid-level disturbance and the sea breeze. These thunderstorms will develop within a weakly sheared environment, likely resulting in pulse thunderstorms. It is possible that one or two of these storms could develop damaging wind gusts with collapsing water-loaded updrafts.

Outside the morning convection, cloud cover will remain very limited as temperatures remain below the convective temperature near 90. Temperatures should warm to 90 degrees by late this morning, then peaking in the mid to upper 90s by mid-afternoon. Sfc dewpoints are forecast to warm into the mid to upper 70s, possibly around 80 near the beaches. The combination of the hot temperatures and elevated dewpoints may result in heat index values between 105 and 110 along the coast from Savannah River to the Santee River. The hot and humid conditions will be highlighted with a Heat Advisory from 11 AM to 7 PM today.

KEY MESSAGE 2: Hot and humid conditions will persist through much of the week.

Upper ridging will maintain control over the region through much of the week, leading to a continued stretch of above normal temperatures. Highs are forecast to peak in the mid to upper 90s each day, with heat indices of 100+. Areas east of I-95 and closer to the coast will see the highest heat indices, generally averaging in the 105-110F range. Heat Advisories could be required. Little relief is expected overnight with lows only falling to the upper 70s/low 80s over most locations. See climate section below for potential records in jeopardy. NWS HeatRisk currently shows a Major (level 3/4) HeatRisk each day, so regardless of heat product issuance, this extended stretch of hot and humid conditions will bring a risk of heat-related impacts, especially to those more vulnerable to heat or those without adequate cooling/hydration.

KEY MESSAGE 3: Typical summertime convection returns this week.

The region will be situated between high pressure offshore and a trough of low pressure inland through much of the week, with ridging the primary feature aloft. Larger scale forcing is lacking, but isolated to perhaps scattered showers and thunderstorms will be possible each day largely due to daytime heating and mesoscale boundaries like the sea breeze. Coverage will be highest in the afternoon and early evenings, before dwindling after sunset with loss of insolation. While the environment favors mainly pulse-type convection, a couple strong to severe storms with damaging wind gusts cannot be ruled out. Locally heavy rainfall is also possible with any storms, but flooding risk is low especially given the hot and dry conditions of late.

AVIATION /06Z MONDAY THROUGH FRIDAY/

6Z TAFs: Terminals will remain VFR with light southwest winds this morning. Scattered thunderstorms are forecast to develop near the sea breeze this afternoon, expected to develop near or over the KCHS and KSAV terminals between 20-24Z. The KCHS TAF will feature a TEMPO for gusty winds and -TSRA, with a PROB30 at KSAV. Convection should dissipated early this evening.

Extended Aviation Outlook: Brief flight restrictions are possible in afternoon showers/thunderstorms this week.

MARINE

Today through tonight: The pressure pattern should support south winds between 10 to 15 kts, with occasional gusts to 20 kts. Wave heights are forecast to favor 3 ft today, increasing to 3-4 ft.

Tuesday through Saturday: Not much change in the pattern this week, with southwest winds in the morning backing more to the south for the afternoon and evenings. Gusts will largely top out in the low 20 kt range, but later in the week, there is a better chance at seeing some 25 knot gusts. Seas will average 2-5 feet.

CLIMATE

Record High Temperatures:

July 7: KCHS: 99/1954

July 8: KCHS: 100/2016 KCXM: 100/1907 KSAV: 101/2010

July 9: KCXM: 99/1986

July 10: KCHS: 100/1986 KCXM: 99/1986 KSAV: 102/1879

July 11: KCHS: 102/1986 KCXM: 100/2001

July 12: KCXM: 97/1966

Record High Minimum Temperatures:

July 6: KCHS: 79/1990 KCXM: 82/2024 KSAV: 78/2024

July 7: KCHS: 80/2017 KCXM: 82/2022 KSAV: 80/1883

July 8: KCHS: 82/2016 KCXM: 83/2016 KSAV: 80/1990

July 9: KCHS: 80/1998 KCXM: 85/1998 KSAV: 80/1883

July 10: KCHS: 81/1986 KCXM: 82/1986

July 11: KCHS: 80/2016 KCXM: 82/2016

July 12: KCHS: 79/2020 KCXM: 82/1998

CHS WATCHES/WARNINGS/ADVISORIES

GA...None. SC...Heat Advisory from 11 AM this morning to 7 PM EDT this evening for SCZ045-148>152. MARINE...None.