Alert archive / Georgia / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 3, NWS Greenville-Spartanburg, SC

March 17, 2018Rabun County, Georgia; Oconee County, South Carolina

NWS Greenville-Spartanburg, SC issued this severe thunderstorm warning at Mar 17, 2018, 9:20 PM EDT for Rabun County, Georgia; Oconee County, South Carolina. It was in force for 40 min. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Mar 17, 2018, 9:20 PM EDT (01:20 UTC)
Expired
Mar 17, 2018, 10:00 PM EDT
In force
40 min
Issued by
NWS Greenville-Spartanburg, SC
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Rabun County, GA, Oconee County, SC

The radar

The Greer radar (KGSP), 102 km from the middle of the area, began a volume at 01:23 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.

What was reported inside it

TimeReportWhereRemark
Mar 17, 9:30 PM EDTHAIL 1Mountain City, GAHAIL UP TO THE SIZE OF QUARTERS, BUT MOSTLY PEA- TO DIME-SIZED.
Mar 17, 10:05 PM EDTTSTM WND DMGSalem, SCTREES AND A POWER LINE REPORTED DOWN NEAR SALEM.
Mar 17, 10:06 PM EDTTSTM WND DMG4 Sw Salem, SC911 CALL CENTER REPORTED A SINGLE TREE DOWN ON A POWER LINE ALONG BETHEL CHURCH RD. TIME APPROXIMATED FROM RADAR.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched one storm report to this severe thunderstorm warning; the first came 10 minutes after it went out.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 1.3 hours before the alert went out and 192 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, Peachtre/Fal Fld, GA at 00:00Z on 2018-03-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 368 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, Peachtre/Fal Fld, GA at 00:00Z on 2018-03-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 155 square meters per square second.1939587897117Sfc1 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
368 J/kg
Mixed-layer CIN
-42 J/kg
Mixed-layer LCL
1222 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
155 m²/s²
0-3 km storm-relative helicity
156 m²/s²
Significant tornado parameter
0.2
Supercell composite
2.9

Open this sounding in Storm Lab

The text

As transmitted.

271 
WUUS52 KGSP 180120
SVRGSP
GAC241-SCC073-180200-
/O.NEW.KGSP.SV.W.0003.180318T0120Z-180318T0200Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Greenville-Spartanburg SC
920 PM EDT SAT MAR 17 2018

The National Weather Service in Greenville-Spartanburg has issued a

* Severe Thunderstorm Warning for...
  Rabun County in northeastern Georgia...
  Oconee County in Upstate South Carolina...

* Until 1000 PM EDT.

* At 920 PM EDT, a severe thunderstorm was located 6 miles northwest
  of Clayton, or 5 miles northwest of Black Rock Mountain State Park,
  moving southeast at 40 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Minor hail damage to vehicles is expected. Expect wind 
           damage to trees and power lines.

* Locations impacted include...
  Walhalla, Clayton, Westminster, Mountain City, Tiger, Dillard, Sky
  Valley, Salem, Lake Rabun and Devils Fork State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Scattered trees and power lines will be blown down in the warned
area. Seek shelter inside an interior room.

Please report damaging winds, hail, or flooding to the National
Weather Service Greenville-Spartanburg by calling toll free, 1, 800,
2 6 7, 8 1 0 1, or by posting on our Facebook page, or Tweet it using
hashtag nwsgsp. Your message should describe the event and the
specific location where it occurred.

&&

LAT...LON 3492 8360 3494 8360 3495 8355 3499 8355
      3500 8315 3496 8292 3494 8291 3454 8308
      3458 8316 3461 8316 3461 8323 3468 8334
      3472 8335 3473 8338 3473 8342 3476 8346
      3490 8363
TIME...MOT...LOC 0120Z 296DEG 34KT 3495 8349 

HAIL...1.00IN
WIND...60MPH
 
$$

ARK
1 follow-up statement
547 
WWUS52 KGSP 180149
SVSGSP

Severe Weather Statement
National Weather Service Greenville-Spartanburg SC
949 PM EDT SAT MAR 17 2018

GAC241-SCC073-180200-
/O.CON.KGSP.SV.W.0003.000000T0000Z-180318T0200Z/
Rabun GA-Oconee SC-
949 PM EDT SAT MAR 17 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1000 PM EDT
FOR CENTRAL RABUN AND CENTRAL OCONEE COUNTIES...

At 949 PM EDT, a severe thunderstorm was located 8 miles northwest of
Walhalla, or near Oconee State Park, moving east at 40 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Minor hail damage to vehicles is expected. Expect wind 
         damage to trees and power lines.

Locations impacted include...
Walhalla, Westminster, Salem, Lake Rabun, Lakemont, Tallulah Gorge
State Park, Oconee State Park, Mountain Rest, Long Creek and Pine
Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Scattered trees and power lines will be blown down in the warned
area. Seek shelter inside an interior room.

Please report damaging winds, hail, or flooding to the National
Weather Service Greenville-Spartanburg by calling toll free, 1, 800,
2 6 7, 8 1 0 1, or by posting on our Facebook page, or Tweet it using
hashtag nwsgsp. Your message should describe the event and the
specific location where it occurred.

&&

LAT...LON 3480 8351 3496 8323 3493 8292 3454 8308
      3458 8316 3461 8316 3461 8323 3468 8334
      3472 8335 3473 8338 3473 8342 3476 8346
TIME...MOT...LOC 0149Z 289DEG 34KT 3485 8317 

HAIL...1.00IN
WIND...60MPH
 
$$

ARK

What forecasters said that day

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

NWS Greenville-Spartanburg, SC wrote its last area forecast discussion before this severe thunderstorm warning went out at Mar 17, 7:55 PM EDT, 1 hour 25 minutes earlier.

Area forecast discussion, Mar 17, 7:55 PM EDT, 1 hour 25 minutes before
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
755 PM EDT Sat Mar 17 2018

.SYNOPSIS...
Somewhat unsettled weather with normal to above normal temperatures
and chances for rain and/or thunder tonight and Monday night as
region experiences the passage of a number of shortwaves, along with
moisture increases.

&&

.NEAR TERM /THROUGH SUNDAY/...
As of 755 PM: Convection off the our west is still strong to severe
but the southern cells are showing some weakening. The northern
cells have maintained their intensity even though they area cycling
somewhat. Therefore, the current watch still look good where severe
storms will be more likely. Can't rule out a severe storm with the
southern cells though. Latest convection allowing models keep the
northern cells strong as they cross the mountains and move east.
They also show redevelopment over the NC southern foothills then
moving across the CLT metro area. However, they disagree on how
strong those cells will be. The guidance also disagrees on whether
the southern cells can hold together and move into NE GA and the
western Upstate. The trends have been to weaken and dissipate those
cells as they move southeast. That said, latest mesoscale analysis
shows a tongue of MUCAPE developing along the I-85 corridor where
dew points have increased through the day into the evening. There's
also quite a bit of effective bulk shear over this area as well. Of
course, we will continue to monitor and issue any products or
updates as needed.

Otherwise, the main short wave driving the storms will move quickly
SE overnight across the mtns and then nearly to the coast by 12Z
Sunday. The passage of the wave should take most of the precip
chances with it, except for a small chance in the pre-dawn hours on
the TN border owing to some lingering moisture. Min temps will
remain well above freezing so that would be all liquid. Expect
clearing sky around daybreak, with high pressure building in from
the NW. Temps are expected to be a bit tricky as we maintain a
gradient across the fcst area in the afternoon...above normal over
northeast GA/upstate SC, but below normal across the NW Piedmont.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
As of 2PM EDT Saturday:  Fairly flat mid-level ridge is progressing
eastward across the region Sunday evening, with precipitation
associated with next upstream wave well to the west and southwest.
Fairly progressive upstream system dives into the south-central
CONUS with the precipitation ahead of it reaching the western parts
of the CWA early Monday morning.  At 12Z Monday, triple-point
surface low is near northeast Oklahoma with a warm front extending
southeast down the NC/GA stateline.  This warm front lifts northward
across the CWA on Monday, bringing an increase in BL moisture and
increasing chances for showers.  Cold front passes through the area
Monday night on the back side of the system.  Frontal passage will
be associated with the strongest chance for precipitation for this
event.  FROPA Tuesday morning will begin drying the BL and end that
round of precipitation, with dry northwesterly advection on Tuesday.
Main upper forcing from upper shortwave holds-off until Tuesday
evening, which will give some chance for light showers later on
Tuesday, despite low-level dry advection, especially over higher
terrain.

Warm frontal passage on Monday will increase dewpoints enough to
create some CAPE Monday afternoon/evening, which along with good low-
level vertical wind shear, will creating some marginal chance for
strong thunderstorms, per the SPC outlook for day 3.

Temperatures will be seasonally warm on Tuesday, behind the warm
front and ahead of the cold front.  Once the cold/dry advection
kicks-in behind the front Tuesday night, temperatures will begin to
drop.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
As of 235 PM EDT Saturday: the extended fcst picks up at 00z on
Wednesday with a deepening southern stream upper trof moving over
the fcst area while upper ridging builds over the Western CONUS.
As we move into Thursday, the upper trof appears to be reinforced
from the backside as it gradually drifts off the Southeast Coast.
The latest long-range model guidance has the trof axis lingering
just off the coast well into Fri and possibly into Sat, as the
upper ridge is flattened just to our west. At the sfc, a complex low
is expected to be centered over the region to start the period. This
system is expected to move off the Southeast Coast during the day as
Canadian high pressure slides in behind it from the north. The
models suggest that a decent amount of deeper-lyr moisture could
linger over part of the CWFA well into Thurs, as the low moves
farther offshore. By early Friday, things should be dry with high
pressure squarely over the region. The next low pressure system is
expected to move eastward out of the plains by the end of the period
and bring another cold front towards the fcst. The latest 12z GFS is
about 24 hrs faster than the ECMWF and Canadian with the approach of
the front, and has it moving thru the CWFA next Sat, whereas the
other 2 models have the fropa on Sunday.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
At KCLT and Elsewhere: Convection off to the west is showing some
weakening as it moves toward the NC border. However, coverage has
not diminished. Convective allowing models still show the best chance
for TSRA at the NC sites. Therefore have retained the TEMPOs but
have adjusted the timing based on the latest radar and guidance. The
southern convection could survive long enough to effect the SC
sites, but chance is too low to include for now. Will of course
amend if the convection holds together. SW wind continues ahead of
the convection then turns NW behind. There will be some LLWS at KAVL
this evening. The wind then goes N and NE during the morning before
turning back to S or SE for the late afternoon/early evening. Do not
expect any restrictions except those associated with TSRA. That
said, there's some indication of MVFR clouds developing by mid-
morning across the NC piedmont. If this does occur, it should
lift/scatter out by noon or shortly thereafter.

Outlook: Moisture returns again from the west with a complex low
pressure system on Monday and Tuesday. Colder air may wrap south
into the region behind the system on Wednesday and some mixed
precipitation cannot be ruled out. Restrictions will be likely in
the Mon-Wed period.

Confidence Table...

            00-06Z        06-12Z        12-18Z        18-00Z
KCLT       High 100%     High 100%     High  88%     High 100%
KGSP       High 100%     High 100%     High 100%     High 100%
KAVL       High 100%     High  92%     High  90%     High 100%
KHKY       High 100%     High 100%     High 100%     High 100%
KGMU       High 100%     High 100%     High 100%     High 100%
KAND       High 100%     High 100%     High 100%     High 100%

The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:

www.weather.gov/gsp/aviation

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.

&&

SYNOPSIS...WJM
NEAR TERM...PM/RWH
SHORT TERM...WJM
LONG TERM...JPT
AVIATION...RWH
Hazardous weather outlook, Mar 17, 4:36 PM EDT, 4 hours 44 minutes before
Hazardous Weather Outlook
National Weather Service Greenville-Spartanburg SC
436 PM EDT Sat Mar 17 2018

NCZ033-048>050-182045-
Avery-Madison-Yancey-Mitchell-
436 PM EDT Sat Mar 17 2018

...SEVERE THUNDERSTORM WATCH 10 IN EFFECT UNTIL MIDNIGHT EDT
TONIGHT...

This Hazardous Weather Outlook is for western North Carolina.

.DAY ONE...Tonight.

Please listen to NOAA Weather Radio or go to weather.gov on the
Internet for more information about the following hazards.

   Severe Thunderstorm Watch.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

..Sunday...No hazardous weather is expected at this time.
..Monday...No hazardous weather is expected at this time.
..Tuesday...No hazardous weather is expected at this time.
..Wednesday...No hazardous weather is expected at this time.
..Thursday...No hazardous weather is expected at this time.
..Friday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

NCZ035>037-051>053-056>059-062>065-068>072-082-501>510-182045-
Alexander-Iredell-Davie-Swain-Haywood-Buncombe-Catawba-Rowan-Graham-
Northern Jackson-Macon-Southern Jackson-Transylvania-Henderson-
Cleveland-Lincoln-Gaston-Mecklenburg-Cabarrus-Union-
Caldwell Mountains-Greater Caldwell-Burke Mountains-Greater Burke-
McDowell Mountains-Eastern McDowell-Rutherford Mountains-
Greater Rutherford-Polk Mountains-Eastern Polk-
436 PM EDT Sat Mar 17 2018

This Hazardous Weather Outlook is for piedmont North Carolina and
western North Carolina.

.DAY ONE...Tonight.

A round of stronger thunderstorms will develop from the northwest
during the evening hours. These thunderstorms will have the potential
to produce a few severe thunderstorms, with damaging wind gusts and
large hail being the main threats this evening. The greatest threat
will be generally along and north of the Interstate 40 corridor this
evening.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

..Sunday...No hazardous weather is expected at this time.
..Monday...No hazardous weather is expected at this time.
..Tuesday...No hazardous weather is expected at this time.
..Wednesday...No hazardous weather is expected at this time.
..Thursday...No hazardous weather is expected at this time.
..Friday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

GAZ010-017-018-026-028-029-SCZ001>014-019-182045-
Rabun-Habersham-Stephens-Franklin-Hart-Elbert-Oconee Mountains-
Pickens Mountains-Greenville Mountains-Greater Oconee-
Greater Pickens-Greater Greenville-Spartanburg-Cherokee-York-
Anderson-Abbeville-Laurens-Union-Chester-Greenwood-
436 PM EDT Sat Mar 17 2018

This Hazardous Weather Outlook is for northeast Georgia and upstate
South Carolina.

.DAY ONE...Tonight.

Scattered thunderstorms may develop from the northwest this evening.
The best chance of thunderstorms with will be across the northern
and eastern Upstate. Cloud-to-ground lightning and briefly gusty
winds will be the primary threats, and some strong gusts and hail
will be possible over the eastern Upstate this evening.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

..Sunday...No hazardous weather is expected at this time.
..Monday...No hazardous weather is expected at this time.
..Tuesday...No hazardous weather is expected at this time.
..Wednesday...No hazardous weather is expected at this time.
..Thursday...No hazardous weather is expected at this time.
..Friday...No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

None.

The office that day

Everything else NWS Greenville-Spartanburg, SC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 17, 8:52 PM EDTSevere Thunderstorm WarningGSPRabun38 min
Mar 17, 9:36 PM EDTSevere Thunderstorm WarningGSPHabersham, Rabun, Stephens39 min
Mar 17, 10:12 PM EDTSevere Thunderstorm WarningGSPFranklin, Hart, Stephens48 min
Mar 17, 10:02 PM EDTSevere Thunderstorm WarningGSPAnderson, Oconee, Pickens43 min
Mar 17, 10:58 PM EDTSpecial Weather StatementGSPAbbeville32 min
Mar 17, 11:28 PM EDTSpecial Weather StatementGSPGreenwood32 min
Mar 17, 11:54 PM EDTSpecial Weather StatementGSPGreenwood36 min
Mar 18, 1:44 AM EDTSpecial Weather StatementGSPChester, York46 min

Nearby

Severe Thunderstorm Warnings in Georgia, 2018Severe Thunderstorm Warnings in South Carolina, 2018Every severe thunderstorm warning in 2018

Sources

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