textproduct: Charleston

WHAT HAS CHANGED

All sections have been updated.

KEY MESSAGES

- 1) Warm and breezy Thursday ahead of an evening cold front.

- 2) Frost/freeze conditions are possible Friday night through Sunday night.

DISCUSSION

KEY MESSAGE 1: Warm and breezy Thursday ahead of an evening cold front.

Thursday will feature warm and breezy conditions ahead of an approaching cold front, with highs topping out in the mid-upper 70s and southwest gusts reaching 25-30 mph during the afternoon. Low and mid levels remain too dry to support rainfall, resulting in a dry frontal passage during the afternoon and evening hours. Strong cold air advection will develop quickly in wake of the front overnight, driving temperatures down into the low to mid 40s inland to around 50 degrees along the coast by early Friday morning.

KEY MESSAGE 2: Frost/freeze conditions are possible Friday night through Sunday night.

Cold air will continue to funnel down into the region in the wake of the front, bringing our first potential frost of the season Friday night into Saturday morning. Low temperatures across portions of interior southeast South Carolina and southeast Georgia are expected to dip down into the mid 30s. The combination of light winds could result in patchy frost formation. The greatest chances for frost will be Saturday night into Sunday morning. Areas west of I-95 in southeast Georgia and along/west of I-95 in the Lowcountry have a chance of reaching freezing temperatures (32 degrees). With the combination of light to calm winds, frost formation seems more probable in these locations. Another chance for frost/freeze returns Monday morning as lows in the mid 30s persist.

Nov 11 13z NBM 10km neighborhood probabilities for emergency management warming shelter planning:

Friday Night/Saturday Morning: Inland Areas Coastal Corridor Temps 35 degrees or colder: 30-60% <5% Temps 32 degrees or colder: 5-20% <5% Temps 30 degrees or colder: <5% <5%

Saturday Night/Sunday Morning: Inland Areas Coastal Corridor Temps 35 degrees or colder: 70-90% 10-30% Temps 32 degrees or colder: 30-60% <5% Temps 30 degrees or colder: 10-30% <5%

Sunday Night/Monday Morning: Inland Areas Coastal Corridor Temps 35 degrees or colder: 40-70% 10-30% Temps 32 degrees or colder: 10-30% 5-10% Temps 30 degrees or colder: 10-20% <5%

Frost Advisories, Freeze Watches and Freeze Warnings may eventually be needed, especially for areas roughly inland of US-17 in the Lowcountry and I-95 in Southeast Georgia.

Detailed information on first freeze dates for the area can be found online at: https://www.weather.gov/media/chs/climate/AverageFirstLastFreezeDates.pdf

AVIATION /00Z THURSDAY THROUGH MONDAY/

VFR conditions are expected to prevail at all terminals through 00Z Thursday. A brief light rain is currently moving offshore and should clear the area over the next hour. No impacts to aviation are expected with this rain. Otherwise, gusty southwesterly to westerly winds are expected to develop Thursday morning and afternoon as a cold front moves through the area. Wind gusts up to 25 knots will be possible.

Extended Aviation Outlook: Southwesterly winds will be strengthening throughout the day on Thursday, producing gusts up to near 25 knots. A cold front will move through Thursday evening, shifting winds out of the west-northwest.

MARINE

Tonight: High pressure will dominate the weather pattern through tonight, but the pressure gradient is anticipated to strengthen well in advance of large-scale trough and associated cold front overnight. Southwest winds will gradually increase to 15-20 kt tonight with gusts remaining shy of 25 kt for most local waters, with an exception for the outer Georgia waters (20-60nm). A Small Craft Advisory has been issued beginning after midnight for 25 kt gusts.

Thursday into Sunday: Winds will continue to increase out of the southwest Thursday morning ahead of the front, becoming gusty by late morning. Likewise, wind-driven seas will build, with 6 foot seas likely limited to the offshore (20-60nm) zones. Additional Small Craft Advisories have been issued Thursday for the nearshore SC waters (from 0-20 nm) and the remaining GA waters from 0-20 nm. Winds shifts to become out of the west- northwest overnight into Friday, with a brief period of weakening winds during the morning/afternoon, before wind gusts pick up again overnight to near 25 knots. This looks to primarily impact the waters 20-60nm offshore from Edisto Beach, SC to Altamaha Sound, GA, with weaker winds elsewhere. Winds decrease Saturday as surface high pressure builds in, remaining in the 10 to 15 knot range with gusts to 20 knots at times into Sunday.

CHS WATCHES/WARNINGS/ADVISORIES

GA...None. SC...None. MARINE...Small Craft Advisory from 10 AM Thursday to 4 AM EST Friday for AMZ360-362-364. Small Craft Advisory from 2 AM Thursday to 10 AM EST Friday for AMZ384.