textproduct: Charleston

SYNOPSIS

High pressure will prevail through Friday. A low pressure system will move through on Saturday, followed by more high pressure next week.

NEAR TERM /THROUGH TONIGHT/

Through Sunset: Occasional breezy westerly winds will quickly ease before sunset.

Tonight: The mid-levels will consist of northwesterly flow overhead this evening, transitioning more towards the west northwest overnight. At the surface, High pressure will be centered roughly over the northeastern Gulf. Meanwhile, very weak surface troughing should form across portions of the Southeast overnight. Dry conditions will persist. Though, high clouds will increase, especially late. Lows will range from the mid 30s far inland to the mid 40s at/near the beaches.

SHORT TERM /FRIDAY THROUGH SUNDAY/

Aloft, the weekend starts off with a zonal flow across the Southeast well in advance of a shortwave trough digging across the Central Plains along the leading edge of a large ridge placed across the Western United States. The shortwave will help develop a low pressure system across the South Central United States on Friday, which quickly advances east across the Deep South late Friday into Saturday. Ahead of the this feature, the sfc pattern features low pressure across the Mid- Atlantic/Northeast states and high pressure to the south on Friday, placing a southwest wind across the local area and resulting in Friday afternoon highs a few degrees warmer than the previous day (highs in the low-mid 60s). Likewise, Friday night temps remain more mild as the area becomes solidly warm- sectored in advance of the low pressure system, leading to lows in the mid-upper 40s inland to low-mid 50s near the coast.

On Saturday, the area remains warm-sectored within a south- southwest sfc flow as a low pressure system advances east across the Deep South and toward the Southeast. Precip chances increase from west to east early morning while temps warm into the mid 60s across Southeast South Carolina and upper 60s/around 70 across Southeast Georgia. This could pose a strong shear/low CAPE setup locally during the day, with the potential for some thunderstorms to become strong and/or severe as the system passes by. Severe weather chances appear higher across Southeast Georgia where breaks in clouds are more likely, which results in warmer sfc temps and larger SBCAPE during peak diurnal heating hours. The Storm Prediction Center has also placed Southeast Georgia in a Marginal Risk for severe weather. Regardless of severe weather potential, rainfall accumulations in the 1/2 to 3/4 inch range are anticipated across the area during a 24-hr span starting just prior to daybreak Saturday morning. A few locations could see locally higher amounts during thunderstorms, prior to dry and cooler high pressure arriving Saturday night. Saturday night lows should dip into the low-mid 40s once the low pressure system shifts offshore. Weather conditions are expected to be much more quiet on Sunday as dry high pressure spreads across the region in wake of low pressure shifting further offshore. Expect dry conditions across land areas by around daybreak while cold air advection within a northerly sfc wind leads to noticeably cooler temps Sunday afternoon. In general, high temps should range in the mid-upper 50s across Southeast South Carolina and around 60 across Southeast Georgia.

LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/

High pressure will spread across the region late weekend and become centered across the Southeast early next week, setting up dry conditions, but modifying temps locally as light southwesterly winds prevail under sunny/mostly sunny skies. In general, high temps should range in the low-mid 60s Monday, then upper 60s/around 70 Tuesday, then lower 70s for most areas away from the beaches on Wednesday. Overnight lows will also trend warmer, starting in the mid-upper 30s inland to low-mid 40s near coastal areas Sunday night and Monday night, then upper 40s/lower 50s Tuesday night.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

18Z TAFs: VFR.

Extended Aviation Outlook: VFR conditions are expected at CHS/JZI/SAV terminals through Friday. Flight restrictions are anticipated Saturday into early Sunday due to showers/thunderstorms associated with a passing low pressure system. VFR conditions should then return Sunday afternoon and prevail through Monday.

MARINE

Through Sunset: Winds and seas are trending lower across the Charleston County coastal waters, so the Small Craft Advisory has expired.

Tonight: High pressure will be centered roughly over the northeastern Gulf, while very weak surface troughing should be located across portions of the Southeast. Expect a westerly moderate breeze to persist. Seas should average 2 ft within 20 nm and 2-3 ft for the GA waters beyond 20 nm.

Friday through Monday: A zonal flow will be in place to start off the weekend with sfc winds primarily offshore, but the approach of a low pressure system across the Deep South will favor a more southerly flow across local waters as the region becomes warm- sectored by late day Friday. The pressure gradient will tighten as the low pressure system approaches Saturday, then will be followed by strong cold air advection in its wake Saturday evening into Sunday, setting up the stage for increasing wind speeds and building seas. Small Craft Advisories will likely be needed for a portion of coastal waters Saturday into Sunday as a result, with greatest potential for 25 kt wind gusts and seas up to 5-7 ft across outer Georgia waters and nearshore waters off the Charleston County Coast. Conditions will then improve by late Sunday morning as dry high pressure presses into the region through early next week.

TIDES/COASTAL FLOODING

The morning high tide cycle will rise above 6 feet MLLW on Friday, remaining elevated through the weekend. Wind directions remain unfavorable for high tidal departures early weekend, but conditions will need to be watched closely for minor coastal flooding across Charleston County Saturday morning due to rainfall associated with a passing low pressure system. On Sunday, sfc winds turn more north- northeast during the morning, likely leading to greater tidal departures. Although rain likely ends before the high tide cycle, minor coastal flooding is currently predicted in the Charleston Harbor. A Coastal Flood Advisory could eventually be needed Sunday morning.

CHS WATCHES/WARNINGS/ADVISORIES

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