textproduct: Charleston

WHAT HAS CHANGED

Aviation section has been updated to reflect the 00z aviation forecast.

KEY MESSAGES

- 1) Dry conditions and above normal temperatures will continue through Thursday.

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

DISCUSSION

KEY MESSAGE 1: Dry conditions and above normal temperatures will continue through Thursday.

Dry high pressure will prevail across the area Wednesday before being forced eastward as a cold front approaches the area Wednesday night and Thursday. Currently, model consensus on the timing of the front suggests that it will begin pushing through the forecast area Thursday afternoon and should shift offshore Thursday evening. The result will be well above normal temperatures each day before the coolest air of the season so far filters in for the late week and the weekend. Wednesday highs are forecast to reach the upper 70s, with similar values for Thursday. Lows will trend upward as well, with upper 40s and low 50s Wednesday morning and mid to upper 50s Thursday morning.

Wednesday afternoon, a mid-level southern stream shortwave will move quickly across the Deep South and towards the forecast area in the afternoon. Hi-res models suggest this could be enough forcing to produce an area of light showers that could move into our southeast GA zones. However, a closer perusal of soundings reveals mostly mid- level moisture with substantial dry air below about 600 mb. Therefore, if this area of showers comes to fruition essentially no measurable rainfall is expected. Also of note, as the front moves in on Thursday we should see breezy conditions due to the combination of tightening pressure gradient, deep diurnal mixing, and the onset of cold-air advection. Frequent gusts into the 25-30 mph range can be expected.

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

Friday: Notably cooler temperatures return heading into the weekend in the wake of a departing cold front. After a brisk start in the 40s to 50s, should see highs warm into the low to mid 60s across the region. West-northwestly winds will also be fairly breezy during this time, with gusts between 20 to 25 mph - so you may still want a grab a jacket before heading out.

Cold air advection continues to surge throughout the overnight period, which may prompt our first frost formation of the season. That being said, wind speeds are still expected to remain high enough to keep the overall concern on the lower end for now. Our best chances for seeing frost look to occur Sunday morning, thanks to clear skies, light winds, and efficient radiational cooling. Otherwise, could see one more round of frost/freeze return Monday morning as cold temperatures linger.

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

Friday Night/Saturday Morning: Inland Areas Coastal Corridor Temps 35 degrees or colder: 20-50% <5% Temps 32 degrees or colder: 5-10% <5% Temps 30 degrees or colder: <5% <5%

Saturday Night/Sunday Morning: Inland Areas Coastal Corridor Temps 35 degrees or colder: 60-80% 10-30% Temps 32 degrees or colder: 20-40% 5% Temps 30 degrees or colder: 10-30% <5%

Sunday Night/Monday Morning: Inland Areas Coastal Corridor Temps 35 degrees or colder: 20-50% 5-10% Temps 32 degrees or colder: 10-20% <5% Temps 30 degrees or colder: 5-10% <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 WEDNESDAY THROUGH SUNDAY/

VFR conditions are expected to prevail at KCHS, KJZI, and KSAV through 00z Wednesday. Winds will be light and variable overnight becoming southwesterly during the afternoon.

Extended Aviation Outlook: VFR conditions will prevail, with westerly winds gusting up to 25 kts of ahead of an advancing cold front Thursday.

MARINE

Through tonight: Modest southwest to west-southwest flow will prevail across the local waters with speeds no more than 10-15 knots. Seas will remain in the 2-3 ft range.

Wednesday Onward: Surface high pressure will continue across the Southeast U.S. through Wednesday, bringing a light to perhaps gentle breeze. Seas will be 2-3 ft within 20 nm and 3-4 ft for the 20-60 nm waters. Winds increase out of the southwest Thursday ahead of an approaching cold front, becoming gusty to near 30 knots. Likewise, wind-driven seas will build.

Small Craft Advisories will likely be needed for our waters starting Thursday afternoon. Winds shift to become out of the west-northwest overnight into Friday, with a brief period of weakening winds during the morning/afternoon before wind speeds pick up again. Winds decrease below Small Craft Thresholds Saturday morning/afternoon, with the northwesterly winds ushering out the 6 feet waves around the same time.

CHS WATCHES/WARNINGS/ADVISORIES

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