textproduct: Charleston

SYNOPSIS

Low pressure will move through the region on Saturday, yielding widespread showers with thunderstorms throughout the day. Then, dry and quiet weather conditions prevail afterwards.

NEAR TERM /THROUGH TONIGHT/

Today: High pressure centered over South Florida will maintain its influence on the Southeast U.S. today as it meanders ever so slowly to the east. This will result in one more quiet day for the South Carolina Lowcountry and Southeast Georgia before a storm system brings some beneficial rains to the region. A weak cold front is forecast to stall well to the north over North Carolina as broad, ill-defined low pressure over the Southern Plains tries to consolidate as it propagates into the Lower-Mid Mississippi Valley. A split flow aloft will persist with the polar jet progged to remain well displaced well to the north and the subtropical jet extending across the Gulf coast. High clouds spreading east with the subtropical jet will gradually expand and thicken as the day progresses. Highs will warm into the mid-upper 60s except lower 60s at the beaches.

Tonight: A southern stream shortwave digging across the lower Mississippi Valley will help consolidate/sharpen low pressure over the Deep South tonight as the subtropical jet remains across the northern Gulf coast. The entire area will remain in the cyclone's warm sector with overnight lows likely to only fall into the mid-upper 40s inland to the mid 50s at the beaches. Rain will move into the far western zones prior to daybreak aided by strengthening warm air advection and increase forcing for ascent aloft. Pops range from 50-70% across far interior Southeast South Carolina into Allendale, Hampton and Colleton Counties in the Lowcountry to 10-30% elsewhere, lowest around the Ludowici and Darien areas.

SHORT TERM /SATURDAY THROUGH MONDAY/

Saturday: As mid-lvl shortwave troughing shifts across the region on Saturday, an associated cold front will march through in the afternoon. Expect low-lvl moisture to spread into the region out ahead of the system with PWATs ranging 1.25 to 1.50 inches. Additionally, the area will remain warm-sectored and temps. are expected to reach into the low to mid 60s across southeast SC and mid to upper 60s across southeast GA. Precipitation chances increase from from west to east in the early morning as this system approaches the region. It's possible to see some thunderstorms in the afternoon as the models continue to indicate a strong shear and low CAPE event. It's important to note that the severe potential remains highest in southeast GA as the magnitude of diurnal heating seems to be more prevalent here than across southeast SC. The Storm Prediction Center has highlighted southeast GA and parts of southeast SC in a Marginal Risk for severe weather for Saturday. In addition to the severe weather potential, rainfall accumulations range from 0.50 to 0.75 inches across a 24-hr period with locally higher amounts possible within thunderstorms. Afterwards, expect dry, cool high pressure to nudge itself into the region behind the cold front with temperatures falling into the low to mid 40s with upper 40s in extreme southeast GA.

Sunday and Monday: Expect conditions to remain rather quiet on Sunday and Monday as high pressure expands across the region in wake of the mid-lvl shortwave shifting further offshore. Noticeable CAA will be present within a northerly flow on Sunday afternoon as temperatures range in the upper 50s to low 60s. Temperatures are a bit warmer on Monday with highs in the low 60s across southeast SC and mid 60s across southeast GA.

LONG TERM /MONDAY NIGHT THROUGH THURSDAY/

Expect quiet and rain-free weather through the period as high pressure continues to dominate the forecast through the end of the week. Temperatures will reach near to above normal values with highs in the upper 60s to low 70s.

AVIATION /12Z FRIDAY THROUGH TUESDAY/

02/12z TAF Discussion: KCHS/KJZI/KSAV: VFR through 03/12z. The leading edge of rain associated with a storm system to the west could approach the terminals right at the end of the 12z TAF period, especially at KCHS and KJZI. No mention was included for 12z TAF cycle, but a mention of rainfall and reduced vsbys/cigs will be needed for the 18z TAF cycle.

Extended Aviation Outlook: Periods of MVFR and IFR possible Saturday into early Sunday as showers and thunderstorms might result in lower ceilings and vsbys. However, conditions should rapidly improve Sunday afternoon and prevail through early next week.

MARINE

Through Tonight: There are no marine concerns. The pressure gradient may tighten enough between high pressure over South Florida and a cold front that stalls over North Carolina to support southwest winds as high as 15-20 kt over the South Santee-Edisto Beach nearshore leg this afternoon into the evening hours. Winds will remain 15 kt or less for all remaining marine legs through tonight. Seas will average 1-3 ft, but will build 2-4 ft over the South Santee-Edisto Beach leg late this afternoon into tonight.

Saturday through Tuesday: Expect a cold front to pass over the local waters Saturday afternoon and yield southwesterly winds at 15 to 20 kts with gusts up to 25 kts possible. Also, widespread showers and thunderstorms associated with the front will pass over the waters throughout the day. However, by Sunday morning, winds should shift northeasterly and wind speeds should decrease to 10 to 15 kts. South- southwesterly swell will mix into the waters on Saturday with seas ranging from 2 to 4 ft (with 4 to 6 ft in the outer Georgia waters). However, seas expected to quickly taper back to 2 to 3 ft by Sunday morning. A Small Craft Advisory have been issued for the outer Georgia waters beginning 15Z Saturday until early Sunday morning given the elevated marine conditions.

TIDES/COASTAL FLOODING

Tides will remain elevated this 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...Small Craft Advisory from 10 AM Saturday to 3 AM EST Sunday for AMZ374.