Alert archive / Georgia / Special Weather Statements in 2017

Special Weather Statement, NWS Charleston, SC

August 31, 2017McIntosh County, Georgia

NWS Charleston, SC issued this special weather statement at Aug 31, 2017, 6:55 PM EDT for McIntosh County, Georgia. It was in force for 50 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 31, 2017, 6:55 PM EDT (22:55 UTC)
Expired
Aug 31, 2017, 7:45 PM EDT
In force
50 min
Issued by
NWS Charleston, SC

County McIntosh County, GA

The radar

The Jacksonville radar (KJAX), 104 km from the middle of the area, began a volume at 22:59 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Jacksonville, FL (KJAX), launched 12:00Z, 10.9 hours before the alert went out and 102 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Jacksonville, FL at 12:00Z on 2017-08-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1403 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Jacksonville, FL at 12:00Z on 2017-08-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 49 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1403 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
744 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
49 m²/s²
0-3 km storm-relative helicity
72 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.4

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Charleston, SC wrote its last area forecast discussion before this special weather statement went out at Aug 31, 6:27 PM EDT, 28 minutes earlier.

Area forecast discussion, Aug 31, 6:27 PM EDT, 28 minutes before
Area Forecast Discussion
National Weather Service Charleston SC
627 PM EDT Thu Aug 31 2017

.SYNOPSIS...
A warm front will lift north of the region through Friday
morning as Tropical Depression Harvey moves across the lower
Mississippi Valley. A cold front will approach from the north
this weekend. High pressure will then prevail early next week
before another front approaches the region during the second
half of next week.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Updated POP and Wx grids to account for observed trends with
ongoing convection. HRRR and 12Z NSSL-WRF have generally
prognosed the behavior and timing of this convection reasonably
well, if not a little slower than reality as is typical. Based
on trends, the convection should be weakening as it moves
offshore of most zones by 01-02Z. Still cannot completely rule
out an isolated tornado closer to the warm front and highest
low-level helicity. After this line pushes offshore, mostly dry
conditions are expected overnight. Increasing low-level jetting
will keep temperatures warmer than last night, mainly mid to
upper 70s.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
Friday and Saturday: Southerly flow between the remnants of Harvey
inland and Atlantic high pressure will continue to advect deep
moisture into the region as a cold front extending from a low
pressure system north of Maine sinks south into North Carolina. This
pattern supports a chance of showers beginning early Friday,
increasing to numerous showers and thunderstorms through the
afternoon and evening. Sufficient surface-based CAPE and shear will
support some strong to marginally-severe thunderstorms, with
greatest potential in northern zones due to closer proximity to the
front. Despite continual degradation of Harvey's remnants, residual
lower surface pressure and heights aloft will make it easy for a
parent low pressure system in Canada to induce secondary, downstream
low pressure formation over the mid-Atlantic states. Guidance
suggests this low pressure will slide offshore into the mid-Atlantic
coastal waters by Sunday evening as it races northeast. Divergence
overhead under the right-entrance region of a passing upper
level jet will contribute to the formation of numerous showers
and thunderstorms over much of the area Friday night into
Saturday, until the bulk of deep-layered moisture shifts
offshore Saturday evening. Temperatures through the period will
be within 1-2 degrees of normal.

Sunday: A relatively drier atmospheric column is expected to fill in
behind the low pressure as it departs the mid-Atlantic region. While
the majority of precipitation will remain offshore, a few showers or
isolated thunderstorms near the coast during the afternoon cannot be
ruled out. Near-normal temperatures are anticipated.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Dry high pressure will build from the west early next week behind a
low pressure system shifting off the Mid-Atlantic and Northeast
coasts. However, a few showers and/or thunderstorms will be possible
near coastal locations Monday, followed by slightly greater precip
coverage on Tuesday as mid/upper lvl energy shifts along the western
edge of a mid/upper lvl ridge axis over Florida. High pressure
should prevail into mid week ahead of a large mid/upper lvl trough
of low pressure expanding over the Central United States. A cold
front associated with this feature should then sweep across much of
the Eastern Conus during the middle of next week. Given the setup, a
southerly flow ahead of the front should support increasing chances
of showers and/or thunderstorms through Wednesday. High temps will
be dependent on cloudy skies and precip coverage, but should peak in
the upper 80s to around 90 degrees, warmest in Southeast Georgia.
Overnight lows should range in the upper 60s/lower 70s Sunday night,
then lower to middle 70s into the middle of next week.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Mainly VFR but guidance coming into better agreement in bringing
a line of thunderstorms through the terms from about 23-02Z,
mainly at KSAV. Strong winds will be possible with these
storms. Low clouds could develop late tonight but confidence is
low so we maintained no mention in the 18Z TAFs.

Extended Aviation Outlook: Probabilities for periods of restrictions
at either terminal due to direct impacts from showers/thunderstorms
will generally increase each day into the weekend. Prevailing VFR
conditions are expected early next week.

&&

.MARINE...
Tonight: Southerly winds to increase as a warm front passes
north through the waters and a stronger low-level jet sets up.
Speeds will increase to 15-20 kt for the Georgia waters with 15
kt across the South Carolina waters. Seas will increase as a
result, reaching 2-4 ft nearshore waters with a solid 4 ft over
the offshore waters. There could be a few gusts to 25 kt after
midnight, mainly near the Gulf Stream, but do not anticipate
the durations to be frequent enough to justify a Small Craft
Advisory.

Friday through Monday: The coastal waters will generally remain
under the influence of Atlantic high pressure, with conditions
expected to remain below Small Craft Advisory levels this weekend
and early next week. In general, south winds will periodically veer
southwest while peaking 15-20 knots early this weekend, before
turning offshore and gradually diminishing to around 10 kts or less
early next week. Seas will range 2-4 feet.

&&

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

&&

NEAR TERM...RJB
SHORT TERM...JMC
LONG TERM...
AVIATION...JMC/RJB
MARINE...JMC/RJB
Hazardous weather outlook, Aug 31, 12:51 PM EDT, 6 hours 4 minutes before
Hazardous Weather Outlook
National Weather Service Charleston SC
1251 PM EDT Thu Aug 31 2017

AMZ330-350-352-354-374-011000-
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-
1251 PM EDT Thu Aug 31 2017

This Hazardous Weather Outlook is for Atlantic coastal waters.

.DAY ONE...This Afternoon 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.

GAZ087-088-099>101-114>119-137>141-SCZ040-042>045-047>052-011000-
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-
1251 PM EDT Thu Aug 31 2017

This Hazardous Weather Outlook is for southeast Georgia and
southeast South Carolina.

.DAY ONE...This Afternoon and Tonight.

Severe Thunderstorms...There is a low potential for a few strong
thunderstorms late this afternoon through early evening capable of
producing damaging winds. Isolated tornadoes will also be possible,
mainly well inland toward the Central Savannah River Area and
southern Midlands.

.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.

In the hours before

Special weather statement, Aug 31, 5:24 PM EDT, 1 hour 31 minutes before
Special Weather Statement
National Weather Service Charleston SC
524 PM EDT THU AUG 31 2017

SCZ042-047-312215-
Inland Jasper-Hampton-
524 PM EDT THU AUG 31 2017

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF HAMPTON AND JASPER
COUNTIES...

At 524 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm over Garnett, or 16 miles north of Springfield,
moving east at 15 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...
Furman, Scotia, Pineland, Shirley, Robertville and Garnett.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Report damage directly to the Charleston National Weather Service at
1-888-383-2024 when it is safe to do so. You can also email your
report to nws.charlestonsc@noaa.gov.

&&

LAT...LON 3269 8133 3274 8113 3262 8105 3251 8123
      3252 8123 3253 8127 3256 8128 3255 8128
      3256 8129 3255 8129 3256 8130 3257 8136
TIME...MOT...LOC 2124Z 272DEG 14KT 3261 8127

NED
Special weather statement, Aug 31, 6:00 PM EDT, 55 minutes before
Special Weather Statement
National Weather Service Charleston SC
600 PM EDT THU AUG 31 2017

SCZ043-044-312245-
Inland Colleton-Dorchester-
600 PM EDT THU AUG 31 2017

...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF COLLETON AND
DORCHESTER COUNTIES...

At 600 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm near Smoaks, or 10 miles southwest of Saint
George, moving east at 20 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...
Saint George, Indian Field, St. George, Reevesville, Smoaks and
Canadys.

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.

Report damage directly to the Charleston National Weather Service at
1-888-383-2024 when it is safe to do so. You can also email your
report to nws.charlestonsc@noaa.gov.

&&

LAT...LON 3316 8042 3293 8064 3313 8089 3314 8088
      3327 8062
TIME...MOT...LOC 2200Z 278DEG 19KT 3311 8072

NED
Local storm report, Aug 31, 6:19 PM EDT, 36 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHARLESTON SC
619 PM EDT THU AUG 31 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0546 PM     TSTM WND DMG     GRAYS                   32.67N  81.02W
08/31/2017                   JASPER             SC   LAW ENFORCEMENT

            SOUTH CAROLINA HIGHWAY PATROL REPORTED A TREE DOWN ON
            HERITAGE ROAD NEAR THE INTERSECTION WITH LAWTONVILLE
            ROAD.

&&

EVENT NUMBER CHS1700613

BSH
Special weather statement, Aug 31, 6:41 PM EDT, 14 minutes before
Special Weather Statement
National Weather Service Charleston SC
641 PM EDT THU AUG 31 2017

SCZ045-312315-
Inland Berkeley-
641 PM EDT THU AUG 31 2017

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

...MARINERS ON LAKE MOULTRIE AND EASTERN LAKE MARION SHOULD SEEK SAFE
HARBOR...

At 641 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm over Eadytown, or 14 miles northwest of Moncks
Corner, moving east at 20 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...
St. Stephen, Bonneau, Southern Lake Moultrie, Eadytown, Cross,
Northern Lake Moultrie, Bonneau Beach and Eastern Lake Marion.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Boaters on Lake Moultrie and the eastern portions of Lake Marion
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
1-888-383-2024 when it is safe to do so. You can also email your
report to nws.charlestonsc@noaa.gov.

&&

LAT...LON 3350 7997 3344 7988 3342 7986 3319 8004
      3330 8026 3341 8023 3345 8019 3346 8016
      3345 8015 3346 8015 3346 8014 3348 8015
      3350 8012 3350 8009 3351 8008
TIME...MOT...LOC 2241Z 273DEG 15KT 3337 8016

NED
Local storm report, Aug 31, 6:43 PM EDT, 12 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHARLESTON SC
643 PM EDT THU AUG 31 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0547 PM     TSTM WND DMG     GRAYS                   32.67N  81.02W
08/31/2017                   JASPER             SC   LAW ENFORCEMENT

            SOUTH CAROLINA HIGHWAY PATROL REPORTED A TREE DOWN ON
            HIGHWAY 3 NEAR THE INTERSECTION WITH GRAYS HIGHWAY.

&&

EVENT NUMBER CHS1700614

BSH
Special weather statement, Aug 31, 6:55 PM EDT, 0 minutes before
Special Weather Statement
National Weather Service Charleston SC
655 PM EDT THU AUG 31 2017

GAZ140-141-312345-
Inland McIntosh-Coastal McIntosh-
655 PM EDT THU AUG 31 2017

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

At 654 PM EDT, National Weather Service doppler radar indicated a
strong thunderstorm over Everett, or 9 miles west of Darien, moving
northeast at 25 mph.

  HAZARD...strong winds 45 to 55 mph, up to penny sized hail and
           excessive cloud to ground lightning.

  IMPACT...Expect minor damage to tree limbs and blowing around of
           light, unsecured objects. Minor hail damage to plants,
           trees and crops is possible. Damage to windshields is
           unlikely. All outdoor activities should cease. Move
           indoors immediately.

Some locations in the path of this storm include...
Darien, Wolf Island, Eulonia, Valona, Little Saint Simons Island,
Cox, Meridian and Crescent.

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 3129 8142 3130 8142 3133 8144 3135 8152
      3140 8158 3144 8161 3148 8162 3164 8129
      3144 8119 3140 8123 3137 8122 3135 8124
      3131 8122 3129 8124
TIME...MOT...LOC 2254Z 247DEG 20KT 3139 8160

The office that day

Everything else NWS Charleston, SC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 31, 5:24 PM EDTSpecial Weather StatementCHSHampton51 min
Aug 31, 5:37 PM EDTSevere Thunderstorm WarningCHSHampton, Jasper46 min
Aug 31, 6:00 PM EDTSpecial Weather StatementCHSDorchester45 min
Aug 31, 6:41 PM EDTSpecial Weather StatementCHSBerkeley34 min
Aug 31, 7:07 PM EDTSpecial Marine WarningCHS83 min
Aug 31, 4:33 PM EDTSpecial Weather StatementCHSTattnall42 min
Aug 31, 4:50 PM EDTSevere Thunderstorm WarningCHSTattnall26 min
Aug 31, 5:11 PM EDTSpecial Weather StatementCHSEvans34 min
Aug 31, 7:19 PM EDTSevere Thunderstorm WarningCHSMcIntosh24 min
Aug 31, 7:26 PM EDTSpecial Weather StatementCHSChatham34 min

Nearby

Special Weather Statements in Georgia, 2017Every special weather statement in 2017

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.