textproduct: Charleston

WHAT HAS CHANGED

All sections and Key Messages were updated.

KEY MESSAGES

- 1) Dry weather and above-normal temperatures will continue through Saturday, followed by a brief cooldown next week.

DISCUSSION

KEY MESSAGE 1: Dry weather and above-normal temperatures will continue through Saturday, followed by a brief cooldown next week.

Deep, subtropical ridging will maintain its influence on the region through Saturday. The ridge will begin to erode Friday and especially into the weekend as series of shortwaves ejecting out of the Central and Northern Plains propagate atop the ridge. Atlantic high pressure centered well offshore will move little through Saturday keeping much of the Southeast U.S. positioned along its western flank. Unfortunately, setup will keep dry and warm conditions in place with little prospects of any drought relief. A cold front is poised to push south through the area Sunday as a much stronger shortwave digs across the Great Lakes and Ohio Valley.

Moisture return head of the front looks meager at best and with model cross sections showing the main corridor of strongest DPVA passing by well to the north, the prospects for measurable rainfall looks pretty dim across the Lowcountry and Southeast Georgia. The 16/01z NBM does highlight 20% pops for the Lowcountry Sunday afternoon/evening, but given the lack of forcing and moisture, these are likely overdone and were lowered to less than 20%. Temperatures through Saturday will remain well above normal for mid-April with record highs likely being challenged both Friday and Saturday afternoons as the flow aloft becomes more west-northwest and 850 hPa temperatures peak in the 16-18C range. The 16/01z NBM deterministic highs are at the very low-end, if not outside of the interquartile range (IQR) for most locations, so some warmer guidance was blended into nudge highs up slightly. See the climate section below record information.

A brief cooldown will occur early next week as a wedge of high pressure builds in from the north and gradually shifts offshore into the Atlantic. Breezy conditions are are likely at the beaches Sunday night into Monday morning where gusty north to northeast winds will occur in response to a tightening of the pressure gradient.

AVIATION /06Z THURSDAY THROUGH MONDAY/

16/06z TAF Discussion: KCHS/KJZI/KSAV: VFR through 17/06z.

Extended Aviation Outlook: Elevated wind gusts are possible Sunday night into Monday morning.

MARINE

Quiet conditions will persist into Saturday with the region remaining along the western flanks of Atlantic high pressure centered well offshore. Sea breeze enhancements along the land/sea interface and Charleston Harbor are likely each afternoon/evening with the intensify of the sea breeze surge likely to wane Friday and Saturday afternoons given a west/northwest flow aloft.

A strong cold front is poised to push through the waters Sunday afternoon with winds quickly ramping up Sunday night into Monday morning in response to post-frontal cold air advection and a rapid tightening of the pressure gradient. North to northeast winds of 20-30 kt are likely with gusts approaching gale force, especially over the 20-60 NM offshore zones. Seas look to peak Monday, ranging from 4-6 ft nearshore waters to 7-10 ft over the offshore waters (highest offshore Georgia waters). Small Craft Advisories are likely and a Gale Watch/Warning could be needed over the offshore zones.

Rip Currents: A Moderate Risk of rip currents remains in place for all beaches through Thursday due to the combination of 2-3 ft swell around 10 seconds, modest onshore flow, and increasing astronomical influences associated with lunar perigee/new moon. An elevated risk for rip currents will likely persist this weekend and especially early next week as a pinched gradient associated with a passing cold front supports a gusty northeast wind event along the Southeast Coast.

CLIMATE

Record High Temperatures:

April 16: KSAV: 92/1967

April 17: KCHS: 91/1967 KCXM: 86/2006 KSAV: 95/1967

April 18: KCHS: 92/1967 KSAV: 93/1967

CHS WATCHES/WARNINGS/ADVISORIES

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