textproduct: Charleston

SYNOPSIS

A cold front will push offshore early this morning. High pressure then builds into the area through Tuesday, followed by another cold front Wednesday night. High pressure will rebuild late in the week.

NEAR TERM /THROUGH TONIGHT/

This morning, satellite water vapor showed an impressive mid-level low tracking SE across the Mid West. To the east, a wide band of moisture extended across the eastern U.S., southwest across northern Mexico. The band of moisture should advance east over the forecast area around dawn this morning. High resolution guidance generally agrees that as the sfc cold front near the GA/SC coast, isolated to scattered weak rain showers will develop near the front. These showers are likely partially supported by the passage of belt of H5 vorticity ahead of the mid-level trough. These showers should yield little to no measurable rainfall before pushing offshore with the front by mid-morning.

In the wake of the front, the pressure gradient will remain steep between the departing front and high pressure centered over the Southern Great Plains. In addition, steady CAA should continue through the day, H85 cooling by around 12 degrees between 12-00Z. The tight pressure gradient, strong CAA, and passing H5 trough will create gusty winds during the daylight hours. The strongest gusts should occur this afternoon, with northwest winds gusting around 30 mph. In addition, dewpoints in the 20s should advect across the forecast area this afternoon, with RH values falling to around 30 percent (see Fire Weather section). Daytime high temperatures should peak in the 60s during the early afternoon.

Tonight, H85 temperatures are forecast to remain in the single digits through the night. The chilly llvl thicknesses combined with thin cloud cover will allow temperatures to fall below normal. Using a blend of guidance, low temperatures are forecast to range from the upper 20s inland to the low 30s along the coast. North winds around 5 mph may push wind chill values below 25 degrees in spots late tonight.

SHORT TERM /MONDAY THROUGH WEDNESDAY/

Cool, dry high pressure will prevail Monday through Tuesday night. A deep longwave upper trough will dig into the eastern United States on Wednesday with a cold front approaching late in the day. Given the considerable increase in moisture on Wednesday ahead of the front, isolated to scattered showers will be possible.

LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/

A few coastal showers may linger into Thursday morning as the cold front sweeps through, then dry, cool weather expected through Saturday.

AVIATION /12Z SUNDAY THROUGH THURSDAY/

12Z TAFs: VFR with gusty winds. West-southwest will remain ahead of the cold front early this morning. Isolated to scattered rain showers may develop across the terminals during the early daylight hours this morning, no restrictions expected. The cold front is timed to push off the coast by 15Z. As the front passes, showers will end and gusty northwest winds will strengthen. TAFs will indicate the strongest winds beginning around 18Z, gusts between 25-30 kts. Winds should veer from the North-northwest this evening with gusts limited to the teens. The rest of the night should feature steady north winds between 5-10 kts with VFR conditions.

Extended Aviation Outlook: VFR.

MARINE

Today: West-southwest will remain ahead of the cold front early this morning. A cold front is timed to push off the coast by mid-morning. As the front passes, weak showers will end and gusty west-northwest winds will strengthen. All marine zones should see solid Small Craft Advisory (SCA) wind conditions today, generally between 25-30 kts. In addition, sea will build through this evening, ranging between 3-6 ft. A tight pressure gradient and cold air advection will maintain gusty conditions outside the Charleston Harbor tonight. The SC/GA Atlantic waters should see SCA remain until around sunrise Monday.

Marine conditions improve on Monday, remaining tranquil through Wednesday night. The next chance for Small Craft Advisories will be Thursday and Thursday night as winds increase behind another cold front.

FIRE WEATHER

Isolated to scattered rain showers may develop across the region during the early daylight hours this morning, yielding little to no rainfall. A cold front is timed to push off the coast by mid- morning. As the front passes, showers will end and gusty northwest winds will strengthen. By this afternoon, humidity values should fall around 30 percent with gusty winds. These weather conditions combined with dry fuels may elevate the wildfire danger this afternoon.

Latest guidance suggest relative humidity values may be a limiting factor and remain just above Red Flag Criteria. We will continue to monitor trends today. Nonetheless, we encourage folks to be cautious with any activity that could cause a spark, as fires can spread quickly under these conditions.

CHS WATCHES/WARNINGS/ADVISORIES

GA...None. SC...Lake Wind Advisory until 7 PM EST this evening for SCZ045. MARINE...Small Craft Advisory until 8 PM EST this evening for AMZ330. Small Craft Advisory until 7 AM EST Monday for AMZ350. Small Craft Advisory until 7 AM EST Monday for AMZ352-354-374.