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.

- 2) A cold front will bring low end rain chances Sunday, followed by a brief cooldown early next week.

DISCUSSION

KEY MESSAGE 1: Dry weather and above-normal temperatures will continue through Saturday.

Mid level ridging will persist over the Southeast through late week. Heights will briefly weaken on Friday as a shortwave passes by to the north, before rebuilding for Saturday. At the surface, high pressure will reside offshore with a trough inland. This pattern will continue to favor warm and dry conditions through Saturday. Temperatures are expected to peak 10-15 degrees above mid-April normals. Highs of 90-95 degrees away from the beaches could put daily records in jeopardy (see climate section below).

Unfortunately, this also means no relief for the ongoing drought. The latest Drought Monitor released this morning now indicates D4/Exceptional Drought over a small portion of interior southeast GA, with an expansion of the D3/Extreme Drought to encompass much of the remaining area.

KEY MESSAGE 2: A cold front will bring low end rain chances Sunday, followed by a brief cooldown early next week.

A mid level trough will swing into the eastern CONUS on Sunday, bringing an associated cold front with it. Moisture content looks quite limited, so while chances for rain are non-zero, the probability is low. If any convection occurs, accumulations will be light as NBM indicates the probability for 24 hr rainfall >0.10" is 15% or less, so no dent in the drought status is expected. Otherwise, temperatures following fropa will be notably cooler than previous days. Monday highs will be below normal before moderating towards the middle of the week. Lows are even expected to dip back into the 40s. Still no notable rain chances in the forecast for the remainder of next week.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

KCHS/KJZI/KSAV: VFR through 17/18z.

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

MARINE

Quiet marine 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 Saturday 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 through the 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.