Special Weather Statement, NWS Charleston, SC

Area Forecast Discussion
National Weather Service Charleston SC
1247 PM EST Thu Dec 30 2021

.SYNOPSIS...
High pressure will generally prevail until a strong cold front
moves through Sunday. Much colder high pressure will then
return into the middle of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
We made some minor changes to the POP/Wx grids based on radar
trends and the new round of models. Otherwise, the mid-levels
consist of southwesterly flow overhead. At the surface, the
main frontal zone is displaced well to the west and northwest
of the forecast area, but a large warm sector will persist.
Within the warm sector, there is a notable surge of low-level
ThetaE progged for this afternoon that will help to focus the
potential for thunderstorm development from west to east into
the forecast area. Likewise, the area of upstream convection
will continue to draw approach our area this afternoon. High
temperatures are still on track to hit the upper 70s to lower
80s. This should allow for plentiful surface destabilization
across the forecast area. Through the mid to late afternoon,
the best coverage should be across southeast South Carolina with
this zone of coverage then gradually slipping further south
into the evening. Southwest winds will remain breezy, gusting
to around 20 mph.

Severe potential: Thunderstorms will overspread the area from
the west this afternoon and evening. There will be the
potential for isolated severe weather. SPC Mesoscale Analysis
indicates MLCAPE values 1,000-1,500. This instability will be
coincident with bulk shear on the order of 40-50 kt. Wind
profiles don't show too much veering, though there should be
enough in the low-levels to help produce some interesting storm
structure and a low end tornado threat. The main risk remains
damaging winds. Though, colder temperatures aloft could also
lead to some hail.

Tonight: Showers and isolated thunderstorms will persist for
much of the evening before the focus shifts offshore through the
overnight. There will still be a potential for severe
thunderstorms in the evening, but that threat will steadily
diminish with time as instability wanes. Expect yet another very
mild night with lows remaining well above normal high
temperatures for late December.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
Friday and Saturday: At the surface, a stalled front will
remain positioned north of the forecast area Friday before
lifting north as a warm front Saturday. Aloft, a mid-level
anticyclone positioned south of the Florida Keys will produce
slight ridging over the forecast area. Isolated to scattered
showers are possible Friday as the aforementioned front lingers
in the vicinity. Saturday features a dry forecast. Temperatures
will continue to be well above normal. The high temperature
forecast features upper 70s to near 80. Overnight lows are
forecast to be in the mid 60s. These temperatures could break
record highs as well as record high minimums. See the Climate
section for more details.

Sunday: A potent mid to upper-level trough will swing through
the eastern CONUS accompanied by its surface low pressure
system. The low pressure system will remain far north of the
forecast area, however it's associated cold front will advance
through the region. Models have been consistent in bringing a
band of showers and thunderstorms through the forecast area,
most likely in the afternoon or evening hours. Model trends will
need to be monitored for the potential for strong to even
severe thunderstorms associated with this front. While ML CAPE
values are predicted to be less than 1000 J/kg, this system has
some impressive dynamics and forcing that could contribute to
the formation of strong to severe thunderstorms. Both the GFS
and the ECMWF have lifted index values that would support a
marginally to moderately unstable environment, along with K
Index values between 30 and 35C, indicative of the potential for
thunderstorm formation. Flooding rainfall is not a major
concern, as models are depicting this system to be fast moving,
therefore any heavy rainfall should be short lived. Temperatures
are forecast in the mid 70s, with some upper 70s along the
Altamaha River. Dew points will be in the mid 60s, a rather
juicy airmass for late December. Temperatures post FROPA will
plummet, with overnight lows much colder - mid to upper 30s
across the region, with a few far inland locations below
freezing.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
High pressure will build in at the surface and persist through
late week, when a cold front could approach the region. Broad
troughing will prevail aloft. A much cooler and drier airmass
will be in place through the first part of the week, before
warming to above normal by Thursday. Prevailing high pressure
will support a dry forecast until late in the period when
isolated showers are possible with an approaching cold front.
Temperatures to start the week will be in the 50s, warming to
the upper 60s by the end of the period. Overnight lows will
follow the same warming trend, starting off near or even below
freezing and warming to the 40s by the end of the period.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
18Z TAFs: Periods of MVFR ceilings and gusty winds will persist
through this afternoon. Showers and occasional thunderstorms
are expected late this afternoon into the evening. The more
likely impacts are for KCHS and KJZI, where we have a TEMPO
group. Though, amendments probably will be needed for all of
the TAFs based on future radar trends. The showers/thunderstorms
end after midnight. Then, ceilings are expected to drop to IFR
and persist through daybreak Friday.

Extended Aviation Outlook: Flight restrictions are possible in
morning low stratus/fog Friday and Saturday as well as with
showers/thunderstorms Sunday. A strong cold front moving through
Sunday will also cause gusty southwesterly winds.

&&

.MARINE...
Today through tonight: Southwest flow will prevail across the
local waters through tonight, with wind speeds mostly peaking
around 15 knots. Speeds into the 15-20 knot range will be
possible at times, mainly for the Charleston County waters and
the outer Georgia waters. Seas will average 2-3 feet most of the
time, but could be up to 4 feet during the periods of strongest
winds. Also of note, thunderstorms could develop across land
areas this afternoon and then move to the coast and across the
coastal waters through the evening hours. Strong wind gusts and
lightning will be the main threats.

Friday through Tuesday: The coastal waters will remain on the
northwestern periphery of surface high pressure through
Saturday. A strong cold front will move through on Sunday. High
pressure will build back in Monday. Tranquil marine conditions
will prevail through Saturday. Starting Saturday night, ahead of
the strong cold front, winds will begin to surge and marine
conditions will deteriorate. Small Craft Advisories will likely
be needed for most, if not all, of the coastal waters, including
the Charleston Harbor. There is the potential for some Gale
force winds overnight Saturday into Sunday. Trends will need to
be monitored. Conditions will slowly improve Monday into
Tuesday.

Sea fog: A warm and moist air mass will remain in place across
the local Atlantic waters into Sunday and as a result some sea
fog could eventually develop over the cooler near shore waters.
Also, some land fog could advect into the marine area. Dense Fog
Advisories will be possible if any dense fog develops and
becomes widespread enough.

&&

.CLIMATE...
Record Daily High Max Temps

Dec 30:
KCHS 82 (2015)
KCXM 78 (2015)
KSAV 83 (2015)

Dec 31:
KCHS 78 (1996, 1984)
KCXM 77 (1996)
KSAV 80 (2015, 1973)

Jan 1:
KCHS 80 (1952)
KCXM 78 (1952)
KSAV 83 (2019)

Jan 2:
KCHS 81 (2017)
KCXM 77 (1952, 1916)
KSAV 79 (2019, 2017, 1952)

Record Daily High Min Temps

Dec 31:
KSAV 66 (2015)

Jan 1:
KCHS 61 (2019, 1973)
KCXM 62 (2019)
KSAV 62 (2019)

Record Warmest Decembers

KCHS 63.5 (2015), 58.8 (1971), 57.1 (1984)
KCXM 63.4 (2015), 61.3 (1931), 59.5 (1971)
KSAV 64.2 (2015), 62.8 (1931), 60.6 (1971)

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.

&&

NEAR TERM...
SHORT TERM...CPM
LONG TERM...CPM
AVIATION...CPM
MARINE...CPM
CLIMATE...

Hazardous Weather Outlook
National Weather Service Charleston SC
346 AM EST Thu Dec 30 2021

AMZ330-GAZ087-088-099>101-SCZ040-042>045-047>052-310900-
Charleston Harbor-Jenkins-Screven-Candler-Bulloch-Effingham-
Allendale-Hampton-Inland Colleton-Dorchester-Inland Berkeley-
Inland Jasper-Beaufort-Coastal Colleton-Charleston-Coastal Jasper-
Tidal Berkeley-
346 AM EST Thu Dec 30 2021

This Hazardous Weather Outlook is for Atlantic coastal waters,
southeast Georgia and southeast South Carolina.

.DAY ONE...Today and tonight.

Severe Thunderstorms: Isolated thunderstorms are expected to move
into portions of southeast South Carolina and southeast Georgia later
today. Damaging wind gusts will be the primary threat, but there will
also be a low end tornado threat as well. The primary time period for
severe thunderstorms will be late this afternoon through the early
evening hours.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter assistance is not anticipated at this time.

AMZ350-352-354-374-310900-
Waters from South Santee River to Edisto Beach SC out 20 NM-
Waters from Edisto Beach SC to Savannah GA out 20 NM-
Waters from Savannah GA to Altamaha Sound GA out 20 NM, including
Grays Reef National Marine Sanctuary-
Waters from Savannah GA to Altamaha Sound GA from 20 to 60 NM-
346 AM EST Thu Dec 30 2021

This Hazardous Weather Outlook is for Atlantic coastal waters.

.DAY ONE...Today and tonight.

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Gales: A strong cold front is expected to move through the Atlantic
coastal waters Sunday night. Behind the front, strong winds are
expected to develop with a period gale force gusts possible. Gale
Watches and Warnings could eventually be needed.

.SPOTTER INFORMATION STATEMENT...

Spotter assistance is not anticipated at this time.

GAZ114>119-137>141-310900-
Tattnall-Evans-Inland Bryan-Coastal Bryan-Inland Chatham-
Coastal Chatham-Long-Inland Liberty-Coastal Liberty-Inland McIntosh-
Coastal McIntosh-
346 AM EST Thu Dec 30 2021

This Hazardous Weather Outlook is for southeast Georgia.

.DAY ONE...Today and tonight.

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter assistance is not anticipated at this time.

Special Weather Statement
National Weather Service Charleston SC
246 PM EST Thu Dec 30 2021

SCZ045-302015-
Inland Berkeley-
246 PM EST Thu Dec 30 2021

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF BERKELEY COUNTY...

...MARINERS ON LAKE MOULTRIE SHOULD SEEK SAFE HARBOR...

At 245 PM EST, National Weather Service doppler radar indicated a
strong thunderstorm over Southern Lake Moultrie, or 7 miles northwest
of Moncks Corner, moving east at 35 mph.

HAZARD...strong winds 45 to 55 mph.

SOURCE...Radar Indicated.

IMPACT...Expect minor damage to tree limbs and blowing around of
         light, unsecured objects.

Some locations in the path of this storm include...
Moncks Corner, Saint Stephen, Bonneau, Jamestown, Southern Lake
Moultrie, Eadytown, Cross and Northern Lake Moultrie.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Boaters on Lake Moultrie should seek safe harbor immediately. If
caught on the open water, stay as low as possible and wear a personal
flotation device. Remember, if you can hear thunder you are at risk
for being struck by lightning.

Report damage directly to the Charleston National Weather Service at
888-383-2024 when it is safe to do so. You can also email your
report to nws.charlestonsc@noaa.gov.

&&

LAT...LON 3343 7987 3343 7988 3340 7986 3337 7980
      3338 7979 3332 7974 3332 7970 3330 7965
      3321 7964 3319 8015 3342 8015 3344 7988
TIME...MOT...LOC 1945Z 264DEG 32KT 3329 8007

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH

NED