textproduct: Charleston

WHAT HAS CHANGED

The Aviation Section has been updated for the 12Z TAF issuance.

KEY MESSAGES

- 1) The next frontal system will bring widespread rainfall late Thursday through Saturday.

DISCUSSION

KEY MESSAGE 1: The next frontal system will bring widespread rainfall late Thursday through Saturday.

Aloft, expect broad mid-lvl troughing to develop across the mid- South on Thursday, and then shift towards the Eastern Seaboard overnight into Friday. At the surface, a surface low will track northeastward across the mid-South on Thursday with an associated cold front. Expect moisture to return to the region on Thursday ahead of the approaching front. Some scattered showers should develop in the far inland counties on Thursday morning and remain in that general area through the evening, before overspreading into the rest of the region overnight into Friday morning. Some weak (MLCAPE < 500 J/kg) instability could be present in southeast Georgia ahead of the front on Thursday night, therefore the mention of thunderstorms has been noted in the forecast. There remains a bit of uncertainty of how quickly the rainfall should clear off the coastline as this timeframe ranges from Friday night into Saturday afternoon. Up to an inch of rainfall is possible across the region over the course of 48 hours (Thurs. morning into Sat. morn). At the moment, flooding appears not be a concern esp. with the ongoing drought conditions. High temperatures will be a few degrees above normal with temps. ranging from upper 60s to low 70s throughout the period.

AVIATION /12Z WEDNESDAY THROUGH SUNDAY/

VFR conditions will prevail at CHS/JZI/SAV terminals through 12Z Thursday. However, southwest winds are expected to become gusty at all terminals by around 15Z mid-late morning (18-23 kt) and persist into late afternoon hours.

Extended Aviation Outlook: VFR conditions likely to persist through at least Thursday. A front should bring flight restrictions late Thursday night into Friday. Occasional flight restrictions could persist into Saturday. Conditions should improve back to VFR Saturday night through Sunday.

MARINE

Today and Tonight: The pressure gradient will become somewhat enhanced between high pressure extending across the western Atlantic and a trough passing to the north. Guidance continues to support some mixing into low-lvl wind fields (1000mb geostrophic winds around 30 kt), supporting a Small Craft Advisory across nearshore SC waters off the Charleston County Coast this morning and through the night (gusts around 25 kt and seas 4-6 ft anticipated). There are hints of some wind gusts approaching 25 kt across southern SC nearshore waters and offshore Georgia waters late day and tonight, but a warm-air advection setup suggests coverage and duration to remain marginal. Given the setup, have opted to keep these waters headline free, but should trends/guidance suggest higher winds late today and tonight, a Small Craft Advisory could need to be issued for these waters as well.

Thursday through Sunday: A cold front will approach from the west late week, yielding elevated winds across local waters Thursday into early Friday. Conditions support the continuation of a Small Craft Advisory across nearshore SC waters off the Charleston County Coast through the day Thursday (gusts around 25 kt and seas 4-6 ft), while southern nearshore SC waters and outer GA waters indicate a solid 15-20 kt wind with perhaps some gusts peaking up to 25 kt. Again, conditions appear marginally supportive of a Small Craft Advisory for these waters so have opted to hold off on an issuance currently, but if trends indicate slightly stronger wind gusts with the approaching front, Small Craft Advisories could be needed Thursday into early Friday. The cold front is then anticipated to shift offshore by Friday night with high pressure returning during the weekend, keeping conditions below Small Craft Advisory levels into early next week.

CHS WATCHES/WARNINGS/ADVISORIES

GA...None. SC...None. MARINE...Small Craft Advisory until 7 PM EST Thursday for AMZ350.