textproduct: Charleston

WHAT HAS CHANGED

Updated all sections and the Aviation section for the 18Z TAFs.

KEY MESSAGES

- 1) Above normal temperatures will persist through the holiday weekend into next week. Heat Advisories could be needed this weekend into early next week as humidity surges back into the region.

- 2) Typical summertime convection returns on Sunday, with chances increasing further into next week.

DISCUSSION

KEY MESSAGE 1: Above normal temperatures will persist through the holiday weekend into next week. Heat Advisories could be needed this weekend into early next week as humidity surges back into the region.

As abnormally strong ridging persists aloft, expect above normal temperatures to continue into early next week. Afternoon temperatures will range from mid to upper 90s (with some spots climbing to 100F) with mostly clear skies through this period. The hottest temperatures will be this holiday weekend as this aforementioned ridge shifts over the Eastern Seaboard. Along with this, forecast soundings suggest that the drier air aloft will mix down yielding afternoon dewpoints in the mid to low 60s today (7/02) and tomorrow (7/03). Thus, this will keep the heat indices below heat advisory criteria for today and tomorrow. However, the potential for Heat Advisories being needed will increase thereafter (esp. along the coastline) with heat indices ranging from 105F to 110F on Sunday onward as moisture surges back into the region. Also, record high temperatures and record high minimums could be challenged through the period (see Climate section below).

KEY MESSAGE 2: Typical summertime convection returns on Sunday, with chances increasing further into next week.

Strong ridging aloft will persist over the eastern CONUS on Friday morning, before slowly breaking down over the weekend and into early next week. While this ridge breaks down, weak troughing should develop across the Eastern Seaboard as a shortwave skirts the U.S./Canada border. This pattern will yield more moisture into the region with PWATs ~2 inches on Sunday supporting a more unstable environment. Thus, the typical summertime afternoon convection should return on Sunday. Thereafter, the chances for precipitation will increase on Monday into mid-to-late week. The afternoon shower and thunderstorm activity each day will depend on how much instability builds through out the day and the timing of the seabreeze. It's likely that these will mostly be cold-pool driven thunderstorms, rather than organized convection, as shear values remain rather limited. Despite this, strong to marginally severe thunderstorms is possible beginning on Sunday and through the mid-to-late week. The main threats within these showers and thunderstorms will likely be damaging wind gusts and locally heavy rainfall. As the sun sets in the evenings, convection will likely dissipate afterwards.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

02/18Z TAFs: VFR conditions will prevail through the TAF period. Latest satellite + observations, it looks like the seabreeze has started making it's way inland here (as of 17Z) and winds will gradually shift out of the southeast at KCHS/KJZI/KSAV as this passes through the terminals. This southeast flow will continue for the remainder of the evening, before becoming calm ~04Z. There was some indication of patchy fog developing a few hours before sunrise, therefore BR was mentioned for KCHS and KJZI at ~10Z/11Z and a little bit earlier for KSAV at ~09Z. However, once the sunrises, the fog will likely dissipate. Not much of a vsby concern as the fog should remain fairly light and 5-6SM was noted with BR.

Extended Aviation Outlook: Afternoon showers and thunderstorms may bring brief flight restrictions late this weekend into early next week.

MARINE

Through tonight: Moderate northeasterly flow will turn more east- southeasterly late this afternoon into the evening, before becoming light and more southeasterly overnight. East- southeasterly swell will continue to slowly fade out of Atlantic waters yielding seas to gradually ease back to 2-3 ft overnight.

Friday through Monday: As an upper-lvl ridging slowly breaks down over the weekend, weak troughing will develop across the waters on Sunday. Light northeasterly winds will take shape on Friday morning, before turning east-southeasterly in the late afternoon. Thereafter, on Saturday (the 4th), winds will be out of the southwest in the early morning, before switching out of the south-southeasterly in the early afternoon. This pattern will yield a typical summertime pattern for the waters as the highest winds will be located along the land/sea interface as the afternoon seabreeze forms and then pushes inland. It's possible to see gusts ~20 kt along the beaches + across the Charleston Harbor as this afternoon seabreeze pushes inland (esp. Saturday through Monday). Expect the winds to slightly veer each night through this period. Seas will range from 2-3 ft through Sunday, before increasing to 3-4 ft on Monday.

Rip Currents: The combination of gusty onshore winds, along with a 2 ft swell at 8 or 9 seconds will continue to generate a Moderate Risk of rip currents at our GA beaches through the evening.

CLIMATE

Record High Temperatures:

July 3: KCHS: 98/2019

July 4: KCHS: 98/2023 KCXM: 98/1902 KSAV: 99/1997

July 5: KCHS: 100/1993 KSAV: 100/1902

July 6: KCHS: 100/1990

July 7: KCHS: 99/1954 KSAV: 101/1977

Record High Minimum Temperatures:

July 5: KCHS: 78/2017 KCXM: 82/2016 KSAV: 78/2016

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

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

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

CHS WATCHES/WARNINGS/ADVISORIES

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