textproduct: Charleston

WHAT HAS CHANGED

Updated the Aviation section for the 00Z TAFs. Removed the key message regarding the potential for a Coastal Flood Advisory across Charleston and Coastal Colleton Counties as latest observations indicated that water levels will remain below the advisory threshold for this evening's high tide.

KEY MESSAGES

- 1) Periodic showers and thunderstorms expected to continue this week within a persistent summertime pattern.

DISCUSSION

KEY MESSAGE 1: Periodic showers and thunderstorms expected to continue this week within a persistent summertime pattern.

Aloft, the pattern will feature broad troughing across the eastern half of the CONUS through the middle of the week. The latter part of the week is less certain, but there is potential for short-lived ridging on Thursday ahead of a vort max lifting out of the western Gulf that shifts across the Deep South and Southeast through Friday. At the surface, a weak boundary is expected to stretch from the Lower MS Valley and across the forecast area through mid week.

Today: Modestly drier air has pushed in from the north, leaving much of the forecast area in an airmass with precipitable water values of 1.5 inches or less. Model guidance captures this and keeps most, if not all, diurnal convection to the south and west of the forecast area. The best chance for isolated to scattered coverage later this afternoon and evening will be southeast GA, primarily along and south of I-16. Overall, not much activity expected today. Just highs rising into the low to mid 90s.

Tuesday: Higher convective coverage looks likely as the deep layer flow takes on a more southwesterly component and allows a better feed of moisture into the region. Precipitable water values should surge back into the 2+ inches range. This improved moisture availability combined with the broad trough aloft and the surface front nearby should yield more shower and thunderstorm activity. Storm motion should be sufficient to prevent too much of a locally heavy rainfall threat, with the exception of locations that potentially see multiple rounds of showers and storms.

Wednesday, Thursday, and into Friday: Some suggestion in model guidance that we could see a relative lull in activity as the broad troughing aloft gets replaced by zonal flow and eventually short wave ridging. However, this could change as we move into Friday and shortwave trough and attending vort max move into the area. Confidence isn't particularly high this far out, but an increase in coverage will need to be monitored closely into the weekend.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

15/00Z: As the showers slowly dissipate across southeastern Georgia, VFR conditions will slowly persist for KCHS/KJZI/KSAV through 13-14Z Tuesday, before showers and thunderstorms begin developing in the mid to late morning hours. Thus, added VCSH for KCHS/KJZI at 15Z, and then at 13Z for KSAV. There are also indications that MVFR ceilings could spread in from the southeast and impact the terminals through 18Z. Thereafter, coverage will slowly increase into the afternoon and into the evening. Highest chances for thunderstorm activity appears to be after 18Z across southeast Georgia and a PROB30 for -TSRA was added for KSAV between 20Z and 21Z.

Extended Aviation Outlook: VFR conditions should mostly prevail through the weekend, with brief periods of flight restrictions possible due to afternoon showers and thunderstorms throughout the week.

MARINE

The local waters will sit between Atlantic high pressure to the east and a surface trough inland for much of the week. This will drive moderate southwest flow through most of the period, with winds occasionally surging into the 15-20 knot range. Periodic stronger flow is expected each afternoon and evening along the land/sea interface with the sea breeze, but conditions should remain below Small Craft Advisory criteria. A better chance of needing Small Craft Advisories will come Friday as the gradient tightens ahead of an approaching front.

CLIMATE

Record High Minimum Temperatures:

June 15 KCHS: 80/2010

June 16: KCHS: 78/1998

June 18 KCHS: 78/2015

June 19 KCHS: 79/2025 KCXM: 81/2025 KSAV: 79/1881

CHS WATCHES/WARNINGS/ADVISORIES

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