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/

Today: The synoptic pattern across the Southeast U.S. will change little today with the region remaining pinned between large high pressure over the Gulf and a broad lee-trough immediately downwind of the Southern Appalachians. Aloft, the longwave trough that has been in place across the eastern CONUS for much of the week will finally begin to dampen and lift out as strong ridging along the Rockies nudges east. Sunny skies will prevail today although the southern fringes of an area of mountain-wave induce cirrus passing to the north over North Carolina could brush the northern areas this morning. Low- level thickness schemes support highs in the lower-mid 60s, except just a tad cooler at the beaches.

Tonight: Quiet conditions will persist into the overnight period. A cold front is forecast to stall north of the area as high pressure over the Gulf meanders east to the Florida Peninsula by daybreak Friday. High clouds will be on the increase with lows ranging from the upper 30s/near 40 inland to the upper 40s/near 50 at the beaches.

Lake Winds: Winds have responded with the passage of a dry cold front. West winds of 15-20 kt with gusts to 25 kt will linger through daybreak, quickly subsiding below advisory thresholds by mid-morning. A Lake Wind Advisory is in effect until 10 AM. Waves as high 2 ft can be expected with the highest winds and most significant wave action occurring over the central and eastern portions of the lake.

SHORT TERM /FRIDAY THROUGH SUNDAY/

Temperatures continue to warm on Friday as a warm front lifts across the region, but with cloud coverage increasing, afternoon temperatures will only reach up in the lower to mid 60s. Moisture advection begins to bring dewpoints back up into the upper 30s to lower 40s by the late afternoon, further rising into the mid 40s to lower 50s by daybreak on Saturday. The warm front will also bring much warmer overnight temptress, largely in the upper 40s to lower 50s.

Weak shortwaves in the mid levels begin to traverse the area overnight, with a surface low pressure moving towards the area from the deep south ahead of the main shortwave. This will bring chances for light to moderate rain showers along with isolated thunderstorms starting early Saturday morning and ending overnight into Sunday as the surface low moves offshore. The bulk of the rainfall is expected to fall during the afternoon hours and into the evening. Agreement amongst the models remains high, all showing increasing probabilities for a wetting rain event. Probabilities for a quarter inch are now in the 85-95% range, chances for a half inch in the 50- 75% range (lowest near the Altamaha Sound), while chances for an inch remaining fairly steady in the 10-30% range.

CAPE is expected to largely remain below 500 J/kg, and looks to only create general thunderstorms with no severe thunderstorms expected. SPC and the various AI/ML output agree, and do not show chances for severe weather across the area. Despite the rain, afternoon temperatures in the lower to upper 60s are expected.

Northwesterly flow aloft moves in behind the exiting shortwave, with a cold front moving through overnight into Sunday. Any remaining showers will be ending throughout the morning hours, with temperatures a touch cooler into the mid 50s to lower 60s.

LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/

For the beginning of next week, a surface high pressure moves into the northeast. This will bring a dry and warming trend, with lower to mid 60s on Monday, mid 60s to lower 70s on Tuesday, and upper 60s to lower 70s on Wednesday.

AVIATION /06Z THURSDAY THROUGH MONDAY/

01/06z TAF Discussion: KCHS/KJZI/KSAV: VFR through 02/06z.

Extended Aviation Outlook: VFR conditions expected to prevail on Friday. Chances for rain return on Saturday, along with possible flight category restrictions from both lowered cigs and vsbys. VFR conditions return Sunday and into next week.

MARINE

Through Tonight: Wind have surged with the passage of a dry cold front and the onset of modest cold air advection. West winds of 20-25 kt with gusts to 30 kt will linger over the South Carolina nearshore waters and the Georgia offshore waters before diminishing later this morning. A Small Craft Advisory is in effect until 10 AM for these waters. Winds still look to peak 15-20 kt with a few gusts to 25 kt over the Georgia nearshore waters. Gusts to 25 kt do not look frequent enough for an advisory at this time. For Charleston Harbor, the risk for frequent gusts to 25 kt continues through mid- morning and a Small Craft Advisory is in effect there as well through 10 AM. West winds will settle to 10-15 kt nearshore waters and 15-20 kt over the Georgia offshore waters this afternoon and continue into the overnight period. Seas 2-4 ft nearshore/3-5 ft offshore subsiding to 1-3 ft nearshore/3-4 ft offshore this afternoon. Seas overnight will range 1-2 ft nearshore/2-3 ft offshore.

Friday through Monday: Westerly winds will remain gusty throughout the day on Friday, turning southwesterly throughout the day. Chances for showers and isolated thunderstorms return on Saturday as a low pressure system moves through, with gusty southwest winds near Small Craft Criteria expected, particularity in the outer Georgia waters and nearshore Charleston county waters Saturday morning/afternoon. 6 foot seas for portions of the same areas are also expected. Winds become northerly on the backside of the aforementioned surface low, decreasing in strength throughout the day on Sunday. No marine concerns expected for Monday.

TIDES/COASTAL FLOODING

Elevated morning high tides rise above 6 feet MLLW on Friday, remaining elevated into the weekend. Wind directions aren't very favorable for high tidal departures, but with a low pressure system and rainfall we'll be watching closely for possible minor coastal flooding Saturday and Sunday morning along the Charleston county coast.

CHS WATCHES/WARNINGS/ADVISORIES

GA...None. SC...Lake Wind Advisory until 10 AM EST this morning for SCZ045. MARINE...Small Craft Advisory until 10 AM EST this morning for AMZ330- 350-352-374.