Special Weather Statement, NWS Charleston, SC

Area Forecast Discussion
National Weather Service Charleston SC
627 AM EST Sun Dec 2 2018

.SYNOPSIS...
A cold front will approach from the west today and push
offshore tonight. Cooler high pressure will then build into the
region through late week. A storm system will likely move
through the southeast states this weekend.

&&

.NEAR TERM /THROUGH TONIGHT/...
Shower activity has been slower to clear out than expected.
Updated near term pops to reflect short term radar trends.
It is unclear if this morning convection will impact convective
trends later this afternoon, but near term guidance is still
suggesting the atmosphere will recover enough by afternoon for
severe tstms.

02/08z surface analysis placed the warm front well to the north
with all of Southeast South Carolina and Southeast Georgia
embedded within a well-defined warm sector. Numerous to
widespread showers continue to move northeast across the region
within an area of strong isentropic assent/warm air advection
centered along the 305K surface. A few tstms have been detected
via LDN and GOES-E GLM over the past few hours within an area
of elevated instability with stronger, more surface-based tstms
displaced to the southwest. Shower/tstm activity is expected to
gradually wind down through daybreak as the corridor strongest
305K isentropic assent propagates off the northeast. All
indications are that most of the morning after daybreak will be
fairly dry with only isolated showers lurking about.

Attention shifts to the afternoon and evening hours as a cold
front approaches from the west. Despite widespread rainfall with
embedded tstms and significant atmospheric overturning early
this morning, all high resolution guidance suggests the
atmosphere will rapidly recover later this morning as strong
warm air advection persists and breaks in the cloud canopy
develop across much of the warm sector. Highs warming into the
upper 70s to near 80 appear quite likely this afternoon with
southerly winds keeping the beaches considerably cooler. These
near record highs and attendant instability coupled with ongoing,
strong moisture advection should support the redevelopment of
numerous showers/tstms beginning by mid-afternoon across the
far interior. This broad line of convection will slowly work
east, reaching the coast by late afternoon/early evening, then
linger along the middle Georgia coast for much of the overnight
period. Pops will be capped at 70% for this afternoon and 50-70%
tonight although higher pops may eventually be needed as
mesoscale features become more apparent and timing among the
various HREF members improve. Lows will range from the mid 50s
across Jenkins, Screven and Allendale counties to the mid 60s
across the far south near the Altamaha River.

Severe Thunderstorms: This afternoon has the potential to be a
fairly organized severe weather event with damaging winds, large
hail and tornadoes possible as a line of thunderstorms moves
east. The size of the event will be highly dependent on how
much instability can recover in the wake of significant rains
and atmospheric overturning that has occurred early this morning
and Friday evening. Most available data sets suggest a
combination of strong warm air and moisture advection within a
persistent low-level jet and breaks in the cloud canopy will
support fairly decent instability profiles for December as
highs warm into the upper 70s to around 80. Modified soundings
support MLCAPE 1500-2000 J/kg with lifted indices as low as -4
to -6C by peak heating. 0-6km bulk shear around 50 kt will be
supportive of bowing line segments and occasional supercells
structures with a minor backing of the low-level wind field
helping induce a slight curvature into elongated hodographs.
This slight backing could support a few tornadoes with SigTor
values peaking in the 2-4 unit range per latest RAP
prognostications.

At this time, it appears the greatest risk for organized severe
thunderstorms will be confined to areas along/west of the I-95
corridor. East of I-95, mainly along the lower South Carolina
Coast including the Charleston Metro Area, it is unclear how
much of the stabilizing influence a possible inland penetration
of the marine layer will be with a more southerly wind regime
expected to prevail. Modified RAP soundings at KCHS certainly
suggest the marine layer could be a major influence with
significant CIN noted in place by late afternoon by the time the
approaching tstms arrive. This will have to be watched through
the day as could quickly drive down the potential for severe
weather reaching that far to the east.

Heavy Rainfall/Flash Flooding: Considerably less rainfall has
fallen across Southeast South Carolina and Southeast Georgia
over the past 6-12 hours compared to southwest and far southern
Georgia where moist convection has been more persistent. The
heaviest rainfall over the local area has been confined to
McIntosh County where as much as 2-3 inches of rain has fallen
in some areas. Although a healthy coverage of deeper, more
surface-based convection is expected later this afternoon into
tonight within a plume of highly anomalous PWATS, it appears
this activity will remain somewhat progressive and less prone to
convective training as convective outflows develop. This should
keep any flooding problems generally limited to Flood Advisory
versus Flash Flood Warning territory. In addition, HREF 1-hr and
3-hr probabilities of >3 inches are not overly high and mostly
clustered across far interior Southeast Georgia. A Flash Flood
Watch will not be issued this far to the east per coordination
with WFO's JAX, FFC and the WPC excessive rainfall desk.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
Monday: A slow moving cold front will become ill defined as it sags
along and off the coast. Lingering rains and isolated tstms are
possible over South GA and South Coastal SC on Monday with chances
less the further inland you go, especially by the afternoon hours.
In lieu of any real cold air advection, temps will likely be
impacted by widespread clouds and coverage of convective rains.
Readings should top out in the lower 70s. The front should move well
offshore Monday night, drier and cooler air will work in from the
northwest with readings in the mid/upper 40s many areas late Monday
night.

Tuesday and Wednesday: Despite a strong cyclonic upper jet over
the southeast states this period, much drier air through the
atmospheric column and sinking lower levels should result in
dry weather despite some vigorous mid level short wave energy
passing through the Carolinas on Wednesday. Temps will continue
to fall below climo at mid week with highs in the lower 60s Tuesday
to only the mid 50s on Wednesday after lows Wednesday morning in the
30s most areas inland from the beaches and barrier islands.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
Cooler high pressure will build over the region from the west
through Thursday, persisting but weakening on Friday. A cold morning
is expected Thursday with inland freezing temps forecast. The next
storm system will likely impact GA and the Carolinas this weekend
with another bout of appreciable rainfall amounts. Temps are
expected to run near or slightly below climo values through the
period.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
There will be a risk for tstms and MVFR vsbys through 15z at
both KCHS and KSAV. ACtivity should then shift farther inland. A
period of MVFR cigs could impact KSAV later this morning as
lower cigs advect northeast out of far southern Georgia. Risk
for tstms will increase by late afternoon/early evening as a
ling of tstms approaches from the west. Continued with
prevailing TSRA at both terminals during this time. Gusty winds
will accompany the line as it moves east.

Extended Aviation Outlook: Flight restrictions are expected to
linger into Monday as low clouds and occasional rains impact the
area along a slow moving cold front. VFR conditions are then
expected to develop Monday night and continue for the remainder of
the period.

&&

.MARINE...
Today: Gusty south to southwest winds will prevail within a
pre-frontal low-level jet. Winds will average 15-20 kt with
gusts to 25 kt nearshore waters and 20-25 kt over the Georgia
offshore and Charleston County waters. Seas will average 4-6 ft
nearshore and 5-8 ft offshore. Small Craft Advisories have been
extended south to include the Georgia nearshore waters. An
advisory is not expected in Charleston Harbor.

Tonight: Gusty southwest winds will turn west as cold front
shifts offshore. Numerous showers/tstms are expected to move
into the waters this evening, which could bring hazardous wind
and hail to the local marine area. Isolated waterspouts will be
possible. Although winds will diminish as they turn west, seas
will take a little while longer to subside below 6 ft. Small
Craft Advisories are forecast to end by late evening nearshore
waters and early Monday for the Georgia offshore waters.

Monday through Thursday: The main issue on Monday along a slow
moving front sagging into the waters will be possible low clouds
and some vsby restrictions over the shelf waters in rain and
fog. Cooler and much drier air will surge offshore Tuesday night
through Wednesday night. SCA conditions are possible from the
pilot buoys seaward during peak surges, however the best chances
for a SCA will be over the GA outer waters where jetting and
mixing profiles are maximized. Conditions will improve late week
as High pressure builds over the area.

&&

.CLIMATE...
Record Highs for 02 December:
KCHS: 80/2015
KCXM: 77/1922
KSAV: 82/1982

Record Rainfall for 02 December:
KCHS: 2.75/2009
KCXM: 3.40/1896
KSAV: 2.70/2009

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 11 PM EST this evening for AMZ352.
     Small Craft Advisory until 1 AM EST Monday for AMZ350-374.
     Small Craft Advisory until 5 PM EST this afternoon for AMZ354.

&&

Hazardous Weather Outlook
National Weather Service Charleston SC
353 AM EST Sun Dec 2 2018

AMZ330-350-352-354-374-GAZ087-088-099>101-114>119-137>141-SCZ040-
042>045-047>052-030900-
Charleston Harbor-
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 extending from 20 to
60 NM-Jenkins-Screven-Candler-Bulloch-Effingham-Tattnall-Evans-
Inland Bryan-Coastal Bryan-Inland Chatham-Coastal Chatham-Long-
Inland Liberty-Coastal Liberty-Inland McIntosh-Coastal McIntosh-
Allendale-Hampton-Inland Colleton-Dorchester-Inland Berkeley-
Inland Jasper-Beaufort-Coastal Colleton-Charleston-Coastal Jasper-
Tidal Berkeley-
353 AM EST Sun Dec 2 2018

...SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON AND EVENING...

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

.DAY ONE...Today and tonight.

Severe Thunderstorms: Numerous showers and thunderstorms will impact
the region this afternoon and evening ahead of a cold front. These
thunderstorms will be capable of producing large hail and damaging
winds in excess of 60 mph along with frequent lightning. Isolated
tornadoes are also possible. Locally heavy rainfall could produce
minor flooding, mainly in low-lying and poor drainage areas.

Locations along and west of Interstate 95 are at the highest risk
for seeing severe thunderstorms this afternoon, although isolated
severe thunderstorms are still possible all the way to the coast,
including the Savannah and Charleston Metro Areas by late afternoon
into the evening hours. The risk for severe thunderstorms will be be
greatest between 2 PM and 9 PM as the thunderstorms move east to the
coast.

Monitor weather conditions throughout the day. Stay tuned to NOAA
Weather Radio, TV or your local news source for the latest severe
weather watches and warnings from the National Weather Service.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Please relay any reports of hazardous weather including, but not
limited to large hail, damaging winds and flooding to the National
Weather Service in Charleston at 1-888-383-2024.

Special Weather Statement
National Weather Service Charleston SC
527 AM EST SUN DEC 2 2018

GAZ099-100-021100-
Bulloch-Candler-
527 AM EST SUN DEC 2 2018

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF BULLOCH AND CANDLER
COUNTIES...

At 526 AM EST, National Weather Service doppler radar indicated a
strong thunderstorm over Stillmore, or 7 miles northwest of Metter,
moving northeast at 55 mph.

  HAZARD...strong winds 45 to 55 mph and excessive cloud to ground
           lightning.

  IMPACT...Expect minor damage to tree limbs and blowing around of
           light, unsecured objects. All outdoor activities should
           cease. Move indoors immediately.

Some locations in the path of this storm include...
Metter, Westside, Portal and Aline.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm and may lead to
flooding of low lying and poor drainage areas. Do not drive your
vehicle through flooded roadways.

&&

LAT...LON 3242 8220 3244 8219 3247 8218 3253 8214
      3256 8209 3254 8203 3259 8201 3262 8194
      3245 8185 3232 8220 3238 8223
TIME...MOT...LOC 1026Z 244DEG 46KT 3244 8217

Special Weather Statement
National Weather Service Charleston SC
546 AM EST SUN DEC 2 2018

GAZ088-100-021115-
Bulloch-Screven-
546 AM EST SUN DEC 2 2018

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF SCREVEN AND BULLOCH
COUNTIES...

At 546 AM EST, National Weather Service doppler radar indicated a
strong thunderstorm over Hopeulikit, or near Middleground, moving
northeast at 60 mph.

  HAZARD...strong winds 45 to 55 mph.

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

Some locations in the path of this storm include...
Statesboro, Middleground, Westside, Portal, Dover and Hopeulikit.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Thunderstorms can produce tornadoes suddenly, sometimes with little
or no warning. Be alert for rapidly changing weather conditions and
be ready to act quickly if severe weather is observed or a warning
is issued.

&&

LAT...LON 3243 8190 3252 8195 3267 8165 3250 8156
TIME...MOT...LOC 1046Z 244DEG 50KT 3250 8186

Special Weather Statement
National Weather Service Charleston SC
713 AM EST SUN DEC 2 2018

GAZ100-101-116-118-SCZ047-021245-
Bulloch-Effingham-Inland Chatham-Inland Bryan-Inland Jasper-
713 AM EST SUN DEC 2 2018

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF BRYAN...BULLOCH...
EFFINGHAM...CHATHAM AND JASPER COUNTIES...

At 713 AM EST, National Weather Service doppler radar indicated
strong thunderstorms along a line extending from near Guyton to near
Ellabell, and moving east at 40 mph.

  HAZARD...strong winds 45 to 55 mph.

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

Some locations in the path of these storms include...
Pooler, Springfield, Lanier, Rincon, Port Wentworth,
Bloomingdale and Guyton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Thunderstorms can produce tornadoes suddenly, sometimes with little
or no warning. Be alert for rapidly changing weather conditions and
be ready to act quickly if severe weather is observed or a warning
is issued.

&&

LAT...LON 3243 8105 3216 8118 3211 8159 3238 8139
TIME...MOT...LOC 1213Z 252DEG 34KT 3234 8134 3216 8148