Alert archive / South Carolina / Areal Flood Advisories in 2021

Areal Flood Advisory 63, NWS Columbia, SC

August 17, 20215 counties in South Carolina

NWS Columbia, SC issued this areal flood advisory at Aug 17, 2021, 3:17 PM EDT for 5 counties in South Carolina. It was in force for 58 min.

The area

The counties it named.

The facts

Issued: Aug 17, 2021, 3:17 PM EDT (19:17 UTC)
Expired: Aug 17, 2021, 4:15 PM EDT
In force: 58 min
Issued by: NWS Columbia, SC
Area: Storm-based polygon

Counties Aiken County, SC, Edgefield County, SC, Lexington County, SC, Newberry County, SC, Saluda County, SC

The radar

The Columbia radar (KCAE), 48 km from the middle of the area, began a volume at 19:20 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

Charleston AFB, SC (KCHS), launched 12:00Z, 7.3 hours before the alert went out and 189 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: 1066 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 639 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 84 m²/s²
0-3 km storm-relative helicity: 92 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.5

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this areal flood advisory 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 areal flood advisory went out at Aug 17, 1:14 PM EDT, 2 hours 3 minutes earlier.

Area forecast discussion, Aug 17, 1:14 PM EDT, 2 hours 3 minutes before

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Hazardous weather outlook, Aug 17, 4:49 AM EDT, 10 hours 28 minutes before

Hazardous Weather Outlook
National Weather Service Columbia SC
449 AM EDT Tue Aug 17 2021

GAZ040-063>065-077-SCZ016-018-020>022-025>031-035-037-038-041-115-
116-135>137-180900-
Lincoln-McDuffie-Columbia-Richmond-Burke-Chesterfield-McCormick-
Newberry-Fairfield-Kershaw-Edgefield-Saluda-Lexington-Richland-Lee-
Aiken-Sumter-Barnwell-Calhoun-Clarendon-Bamberg-Northern Lancaster-
Southern Lancaster-Northwestern Orangeburg-Central Orangeburg-
Southeastern Orangeburg-
449 AM EDT Tue Aug 17 2021

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

.DAY ONE...Today and tonight.

Periods of heavy rainfall may be possible today and tonight due to
slow moving showers and thunderstorms associated with the remnants of
Fred. Depending on how heavy the rainfall is, there may be some
localized flash flooding of small streams and low-lying areas.

There is also a threat for isolated tornadoes as the remnants of Fred
pass west of the area this morning and through this evening.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be required at some point today.

In the hours before

Special weather statement, Aug 17, 11:32 AM EDT, 3 hours 45 minutes before

Special Weather Statement
National Weather Service Columbia SC
1132 AM EDT Tue Aug 17 2021

GAZ040-064-SCZ018-171615-
Lincoln GA-Columbia GA-McCormick SC-
1132 AM EDT Tue Aug 17 2021

...A strong thunderstorm will impact portions of Columbia,
southeastern Lincoln, northwestern Richmond, and southeastern
McCormick Counties through 1215 PM EDT...

At 1131 AM EDT, Doppler radar was tracking a strong thunderstorm near
Appling, or near Grovetown, moving north at 25 mph.

...Boaters on Lake Strom Thurmond Should Seek Safe Harbor...

HAZARD...Winds in excess of 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Grovetown, Evans, Harlem, Appling, Clarks Hill Recreation Area, J.
Strom Thurmond Dam, Riverwood, Mistletoe State Park, Hamilton Branch
State Park, Parksville, Plum Branch, Liberty Park Community Center,
Winfield, Modoc, Scott's Landing, Knox Scout Reservation, Double
Branches, Columbia County Jail, Wildwood Park and Modoc Boat Ramp.

This includes Interstate 20 in Georgia between mile markers 179 and
191.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

A Tornado Watch remains in effect until 700 PM EDT for east central
Georgia...and central South Carolina.

&&

LAT...LON 3389 8238 3386 8214 3383 8212 3376 8217
      3375 8216 3373 8218 3369 8217 3369 8214
      3365 8212 3342 8219 3340 8222 3342 8234
      3349 8240 3353 8239 3354 8241
TIME...MOT...LOC 1531Z 189DEG 24KT 3349 8230

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

Local storm report, Aug 17, 2:35 PM EDT, 42 minutes before

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Local storm report, Aug 17, 2:43 PM EDT, 34 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 17, 12:31 PM EDT	Areal Flood Advisory	CAE	Aiken, Edgefield, McCormick, Saluda	59 min
Aug 17, 12:59 PM EDT	Tornado Warning	CAE	Edgefield	46 min
Aug 17, 1:34 PM EDT	Areal Flood Advisory	CAE	Aiken, Edgefield, Saluda	56 min
Aug 17, 1:44 PM EDT	Tornado Warning	CAE	Edgefield, McCormick, Saluda	17 min
Aug 17, 1:55 PM EDT	Tornado Warning	CAE	Aiken, Edgefield, Lexington, Saluda	50 min
Aug 17, 2:08 PM EDT	Tornado Warning	CAE	Aiken	37 min
Aug 17, 2:31 PM EDT	Tornado Warning	CAE	Barnwell	44 min
Aug 17, 3:12 PM EDT	Tornado Warning	CAE	Lexington, Saluda	48 min
Aug 17, 3:48 PM EDT	Tornado Warning	CAE	Fairfield, Lexington, Newberry, Richland	42 min
Aug 17, 4:25 PM EDT	Severe Thunderstorm Warning	CAE	Fairfield, Newberry	50 min
Aug 17, 4:31 PM EDT	Areal Flood Advisory	CAE	Fairfield, Lexington, Newberry, Richland, Saluda	59 min
Aug 17, 4:48 PM EDT	Severe Thunderstorm Warning	CAE	Bamberg, Orangeburg	42 min
Aug 17, 4:56 PM EDT	Tornado Warning	CAE	Orangeburg	34 min
Aug 17, 5:29 PM EDT	Areal Flood Advisory	CAE	Calhoun, Kershaw, Lexington, Richland	3 hr
Aug 17, 5:29 PM EDT	Tornado Warning	CAE	Calhoun, Orangeburg	46 min
Aug 17, 7:43 PM EDT	Special Weather Statement	CAE	Aiken	32 min
Aug 17, 11:32 AM EDT	Special Weather Statement	CAE	Columbia	43 min

Nearby

Areal Flood Advisories in South Carolina, 2021 Every areal flood advisory in 2021

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.