Alert archive / South Carolina / Flash Flood Warnings in 2017

Flash Flood Warning 17, NWS Columbia, SC

July 23, 2017Richland County, South Carolina

NWS Columbia, SC issued this flash flood warning at Jul 23, 2017, 6:58 PM EDT for Richland County, South Carolina. It was in force for 92 min. 5 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: Jul 23, 2017, 6:58 PM EDT (22:58 UTC)
Expired: Jul 23, 2017, 8:30 PM EDT
In force: 92 min
Issued by: NWS Columbia, SC
Area: Storm-based polygon
Flood severity: None

County Richland County, SC

The radar

The Columbia radar (KCAE), 10 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.

What was reported inside it

Time	Report	Where	Remark
Jul 23, 7:03 PM EDT	FLASH FLOOD	Columbia, SC	SOCIAL MEDIA REPORT WITH IMAGE OF FLASH FLOODING AT CORNER OF LINCOLN AND GERVAIS STREETS.
Jul 23, 7:10 PM EDT	FLASH FLOOD	1 Sse Columbia, SC	FLASH FLOODING OBSERVED ON USGS WEBCAM ROCKY BRANCH AT WHALEY STREET. WATER FLOWING OVER ROADWAY AND CAR PARTIALLY SUBMERGED.
Jul 23, 7:17 PM EDT	FLOOD	1 N Columbia, SC	SCHP REPORTED ROADWAY FLOODING SC-277 AND SUNSET BLVD.
Jul 23, 7:23 PM EDT	FLASH FLOOD	1 Sse Columbia, SC	COLUMBIA FIRE DEPT. REPORTED 1 PERSON TRAPPED AND RESCUED FROM FLOODED VEHICLE AT WHALEY AND MAIN STREETS. NO INJURIES.
Jul 23, 7:29 PM EDT	FLASH FLOOD	1 Nnw Columbia, SC	SOCIAL MEDIA REPORT WITH IMAGE OF FLOODED ROADWAYS AT 1024 ELMWOOD AVE.

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 4 storm reports to this flash flood warning; the first came 5 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

Charleston AFB, SC (KCHS), launched 12:00Z, 11.0 hours before the alert went out and 154 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1307 J/kg
Mixed-layer CIN: -48 J/kg
Mixed-layer LCL: 933 m above ground
0-6 km bulk shear: 7 kt
0-1 km storm-relative helicity: -49 m²/s²
0-3 km storm-relative helicity: -40 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

677 
WGUS52 KCAE 232258
FFWCAE
SCC079-240030-
/O.NEW.KCAE.FF.W.0017.170723T2258Z-170724T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Columbia SC
658 PM EDT SUN JUL 23 2017

The National Weather Service in Columbia has issued a

* Flash Flood Warning for...
  Central Richland County in central South Carolina...

* Until 830 PM EDT

* At 657 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. 1.00 inch of rain has fallen in 
  downtown Columbia in the last half hour.
  
  Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Columbia, Forest Acres and Five Points. 

LAT...LON 3395 8103 3398 8105 3400 8106 3405 8100
      3401 8093

$$

awp/da

1 follow-up statement

908 
WGUS72 KCAE 240020
FFSCAE

Flash Flood Statement
National Weather Service Columbia SC
820 PM EDT SUN JUL 23 2017

SCC079-240030-
/O.CON.KCAE.FF.W.0017.000000T0000Z-170724T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Richland SC-
820 PM EDT SUN JUL 23 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 830 PM EDT FOR
CENTRAL RICHLAND COUNTY...

At 816 PM EDT, local law enforcement reported several roadways 
flooded in downtown Columbia. The heavy rain has moved out of the 
area. But street flooding will continue. An urban and small stream 
flood advisory will remain in effect for runoff.

Some locations that will experience flooding include...
Columbia, Forest Acres and Five Points. 

LAT...LON 3395 8103 3398 8105 3400 8106 3405 8100
      3401 8093

$$

awp

What forecasters said that day

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

NWS Columbia, SC wrote its last area forecast discussion before this flash flood warning went out at Jul 23, 5:25 PM EDT, 1 hour 33 minutes earlier.

Area forecast discussion, Jul 23, 5:25 PM EDT, 1 hour 33 minutes before

Area Forecast Discussion
National Weather Service Columbia SC
525 PM EDT Sun Jul 23 2017

.SYNOPSIS...
Upper level ridging will weaken across the area today as the
upper level trough digs over the eastern US. A bermuda high will
provide very warm and humid conditions through Monday with
scattered afternoon and evening showers and thunderstorms. A
weak cool front will stall over the area Tuesday, then move
southward into southern Georgia on Wednesday before dissipating,
providing somewhat cooler weather and a continued threat for
scattered thunderstorms. High pressure will become re-
established for the end of the week.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Thunderstorms have developed across much of the western Midlands
and Pee Dee with some locally very heavy rainfall. Rain rates
approaching 4 inches per hour have been noted in WSR-88D
returns so potential for localized flooding will continue to be
monitored. Hail potential remains low...however some hail in the
strongest cells has been reported. Expect thunderstorms to
continue slowly moving southward into the central Midlands over
the next couple of hours along with development moving in from
the coast and a few cells in the CSRA. With sunset convection
will begin diminishing...but with numerous outflow boundaries
being produced expect some to intersect and generate new cells
into the late evening/early tonight hours. Convection will end
during the early morning hours with some mid and upper level
debris cloudiness through daybreak keeping low temperatures in
the mid to upper 70s for most locations.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
The forecast area will remain on the western edge of the Bermuda
high through Tuesday night, while heights aloft slowly drop as a
longwave trof becomes established over eastern North America.
This combination will lead to hot afternoons with max temps
generally in the lower to mid 90s, and maximum heat indices a
little above 100. The combination of developing steep low level
lapse rates each afternoon and weak vorticity aloft will lead
to scattered afternoon and evening convection. PWs will range
from 1.8 inches to 2.2 inches across the CWA, so any slow moving
convection could dump some locally heavy rain in spots.

Min temps will remain quite warm with lows in the mid to upper
70s most places.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
On Wednesday, a weak front will slowly slide through the CWA as
a small area of low pressure develops off of the South Carolina
coast and moves to the northeast. It's main impact will be to
dry the air out a little bit Wednesday night and Thursday, but
max temps on Thursday afternoon will still be in the 90s as an
increase in sunshine will offset any weak cool advection that
tries to set up. Thursday will also see the lowest chance for
afternoon and evening convection for the week.

By Friday, the main global models begin to diverge with details,
but the overall pattern indicates a digging shortwave will move
into the southeastern states on Friday. This will cause an
increase in the deep southwesterly flow, allowing moisture to
quickly return in the form of clouds and scattered convection,
especially during the second half of the day. The weekend
contains a lot of uncertainty as the GFS shows a rather strongly
amplified pattern for july with a significantly deep trough
carving out over the southeastern states, while the ECMWF is
much more progressive with the digging shortwave on Saturday and
instead is more focused on the next shortwave, which is in the
7-10 day period and not part of this package. I have gone for
generally unsettled weather due to the mean trof, without
concentrating too much on the individual shortwaves. This means
slightly above normal chances for rain and slightly below
normal afternoon temps due to increased cloud cover.

&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
Convection expected at the terminals over the next several
hours.

Thunderstorms have developed across the area with cells around
all terminals. Main concerns with thunderstorms remain the
potential for damaging wind gusts along with locally very heavy
rainfall. Have included tempo for all terminals...except OGB...
through 24/01z. Convection will diminish with sunset...however a
few cells are expected to linger into the overnight. Have also
included MVFR fog at AGS/OGB as coming rainfall will increase
potential. All sites will be VFR from 14z through the end of
the period with cumulus developing during the late morning hours
through the end of the period as another round of convection is
expected Monday afternoon.

EXTENDED AVIATION OUTLOOK...Increasing confidence in
restrictions in mainly afternoon/evening thunderstorms through
Wednesday. We could also see some morning cig restrictions from
stratus by Tuesday and Wednesday. The convection looks to
decrease on Thursday, but should pick right back up again by
Friday.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.

&&

Hazardous weather outlook, Jul 23, 3:52 AM EDT, 15 hours 6 minutes before

Hazardous Weather Outlook
National Weather Service Columbia SC
352 AM EDT Sun Jul 23 2017

GAZ040-063>065-077-SCZ015-016-018-020>022-025>031-035>038-041-240800-
Lincoln-McDuffie-Columbia-Richmond-Burke-Lancaster-Chesterfield-
McCormick-Newberry-Fairfield-Kershaw-Edgefield-Saluda-Lexington-
Richland-Lee-Aiken-Sumter-Barnwell-Orangeburg-Calhoun-Clarendon-
Bamberg-
352 AM EDT Sun Jul 23 2017

This Hazardous Weather Outlook is for the Midlands of South Carolina
and the Central Savannah River area of Georgia.

.DAY ONE...Today and Tonight.

The probability for widespread hazardous weather is low.

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

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

In the hours before

Local storm report, Jul 23, 4:52 PM EDT, 2 hours 6 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE COLUMBIA SC
452 PM EDT SUN JUL 23 2017

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

0411 PM     TSTM WND DMG     2 WSW RUBY              34.73N 80.22W
07/23/2017                   CHESTERFIELD       SC   LAW ENFORCEMENT

            TREES IN ROADWAY WALTER GULLEDGE ROAD AND SC
            265.

&&

DA

Local storm report, Jul 23, 5:53 PM EDT, 1 hour 5 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE COLUMBIA SC
553 PM EDT SUN JUL 23 2017

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

0537 PM     TSTM WND DMG     9 N CHAPPELLS           34.31N 81.84W
07/23/2017                   NEWBERRY           SC   LAW ENFORCEMENT

            TREE DOWN AT SC56 AND BELFAST RD.

&&

DA

Local storm report, Jul 23, 6:01 PM EDT, 57 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE COLUMBIA SC
601 PM EDT SUN JUL 23 2017

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

0527 PM     TSTM WND DMG     6 ESE KERSHAW           34.51N 80.49W
07/23/2017                   KERSHAW            SC   LAW ENFORCEMENT

            MULTIPLE TREES DOWN MT. PISGAH RD AND HWY
            341.

&&

DA

Local storm report, Jul 23, 6:05 PM EDT, 53 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE COLUMBIA SC
605 PM EDT SUN JUL 23 2017

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

0527 PM     TSTM WND DMG     8 ENE RIDGEWAY          34.35N 80.84W
07/23/2017                   FAIRFIELD          SC   CO-OP OBSERVER

            NWS CO-OP OBSERVER REPORTED PECAN TREE DOWN.

&&

AWP

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 23, 3:27 PM EDT	Severe Thunderstorm Warning	CAE	Chesterfield	63 min
Jul 23, 4:01 PM EDT	Severe Thunderstorm Warning	CAE	Lancaster	44 min
Jul 23, 4:12 PM EDT	Areal Flood Advisory	CAE	Chesterfield	2 hr
Jul 23, 4:28 PM EDT	Severe Thunderstorm Warning	CAE	Chesterfield, Lancaster	62 min
Jul 23, 4:39 PM EDT	Flash Flood Warning	CAE	Chesterfield	2 hr
Jul 23, 4:52 PM EDT	Severe Thunderstorm Warning	CAE	Chesterfield, Kershaw, Lancaster	53 min
Jul 23, 5:19 PM EDT	Severe Thunderstorm Warning	CAE	Fairfield, Kershaw, Richland	56 min
Jul 23, 5:28 PM EDT	Severe Thunderstorm Warning	CAE	Fairfield, Newberry, Saluda	62 min
Jul 23, 6:24 PM EDT	Severe Thunderstorm Warning	CAE	Aiken, Edgefield, Newberry, Saluda	66 min
Jul 23, 6:38 PM EDT	Severe Thunderstorm Warning	CAE	Kershaw, Lexington, Richland	67 min
Jul 23, 6:49 PM EDT	Severe Thunderstorm Warning	CAE	Aiken, Barnwell, Edgefield, Lexington, Orangeburg	56 min
Jul 23, 6:52 PM EDT	Areal Flood Advisory	CAE	Lexington, Richland	2 hr
Jul 23, 7:41 PM EDT	Severe Thunderstorm Warning	CAE	Aiken, Edgefield, McCormick	64 min
Jul 23, 7:53 PM EDT	Severe Thunderstorm Warning	CAE	Edgefield, McCormick	67 min

Nearby

Flash Flood Warnings in South Carolina, 2017 Every flash flood warning 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.