Alert archive / North Carolina / Flash Flood Warnings in 2021

Flash Flood Warning 3, NWS Greenville-Spartanburg, SC

March 31, 2021Jackson County, Macon County, Swain County, North Carolina; Rabun County, Georgia

NWS Greenville-Spartanburg, SC issued this flash flood warning at Mar 31, 2021, 9:57 AM EDT for Jackson County, Macon County, Swain County, North Carolina; Rabun County, Georgia. It was in force for 5 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Mar 31, 2021, 9:57 AM EDT (13:57 UTC)
Expired: Mar 31, 2021, 3:00 PM EDT
In force: 5 hr
Issued by: NWS Greenville-Spartanburg, SC
Area: Storm-based polygon
Flood severity: None

Counties Rabun County, GA, Jackson County, NC, Macon County, NC, Swain County, NC

The radar

The Knoxville radar (KMRX), 113 km from the middle of the area, began a volume at 13:58 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

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 2.0 hours before the alert went out and 219 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: 111 J/kg
Mixed-layer CIN: -58 J/kg
Mixed-layer LCL: 562 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 205 m²/s²
0-3 km storm-relative helicity: 296 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

099 
WGUS52 KGSP 311357
FFWGSP
GAC241-NCC099-113-173-311900-
/O.NEW.KGSP.FF.W.0003.210331T1357Z-210331T1900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Greenville-Spartanburg SC
957 AM EDT Wed Mar 31 2021

The National Weather Service in Greenville-Spartanburg has issued a

* Flash Flood Warning for...
  North Central Rabun County in northeastern Georgia...
  Southwestern Jackson County in western North Carolina...
  Macon County in western North Carolina...
  South Central Swain County in western North Carolina...

* Until 300 PM EDT.

* At 957 AM EDT, With the likelihood of additional heavy rain this 
  morning, as much as 4 inches of rain may accumulate across Western 
  and Southern Macon County. Numerous tributaries of the Little 
  Tennessee and Nantahala Rivers are expected to flood, and 
  developing high water conditions are expected throughout the 
  Highway 441 corridor.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar and automated gauges.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Heavy rain is increasing the risk of landslides, especially in areas 
where slides have occurred in the past. Be especially alert if you 
are near a stream, especially at the base of a mountain or in a 
cove. Watch for loose-moving soil and rocks or a sudden increase in 
streamflow. Leave the area quickly if this is observed. When driving 
along roads where the terrain is steep or rocky, watch and listen 
for falling rocks, mud, trees and other debris.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3529 8366 3534 8333 3524 8329 3524 8322
      3517 8321 3508 8313 3506 8316 3500 8309
      3499 8348 3500 8352 3507 8357 3511 8362
      3513 8362 3514 8365 3516 8366 3516 8374
      3520 8372 3520 8373

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

2 follow-up statements

263 
WGUS72 KGSP 311551
FFSGSP

Flash Flood Statement
National Weather Service Greenville-Spartanburg SC
1151 AM EDT Wed Mar 31 2021

GAC241-NCC173-311601-
/O.CAN.KGSP.FF.W.0003.000000T0000Z-210331T1900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Rabun GA-Swain NC-
1151 AM EDT Wed Mar 31 2021

...FLASH FLOOD WARNING IS CANCELLED FOR CENTRAL SWAIN COUNTY...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

A Flash Flood Watch remains in effect until 800 PM EDT Wednesday for 
portions of northeast Georgia, western North Carolina and upstate 
South Carolina.

LAT...LON 3524 8339 3521 8329 3524 8322 3517 8321
      3508 8313 3506 8316 3500 8310 3499 8347
      3500 8351 3500 8352 3501 8353 3502 8352
      3504 8355 3507 8357 3508 8358 3509 8359
      3511 8362 3518 8358 3519 8349 3524 8344

$$

NCC099-113-311900-
/O.CON.KGSP.FF.W.0003.000000T0000Z-210331T1900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jackson NC-Macon NC-
1151 AM EDT Wed Mar 31 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 3 PM EDT THIS 
AFTERNOON FOR SOUTH CENTRAL JACKSON AND MACON COUNTIES...

At 1151 AM EDT, Doppler radar was indicating that the threat of 
heavy rain had ended for the time being, but locally excessive 
runoff will linger into this afternoon for areas from Otto to 
Franklin to Highlands and select tributaries of the Little Tennessee 
River.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3524 8339 3521 8329 3524 8322 3517 8321
      3508 8313 3506 8316 3500 8310 3499 8347
      3500 8351 3500 8352 3501 8353 3502 8352
      3504 8355 3507 8357 3508 8358 3509 8359
      3511 8362 3518 8358 3519 8349 3524 8344

FLASH FLOOD...RADAR INDICATED

$$

938 
WGUS72 KGSP 311806
FFSGSP

Flash Flood Statement
National Weather Service Greenville-Spartanburg SC
206 PM EDT Wed Mar 31 2021

NCC099-311816-
/O.CAN.KGSP.FF.W.0003.000000T0000Z-210331T1900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Jackson NC-
206 PM EDT Wed Mar 31 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTH CENTRAL JACKSON 
COUNTY...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

A Flash Flood Watch remains in effect until 800 PM EDT for portions 
of northeast Georgia, western North Carolina and upstate South 
Carolina.

LAT...LON 3514 8330 3517 8324 3516 8321 3513 8319
      3511 8318 3509 8315 3508 8314 3507 8317
      3506 8317 3506 8316 3500 8311 3499 8347
      3500 8351 3500 8352 3501 8353 3507 8345
      3512 8343 3514 8342 3514 8340

$$

NCC113-311900-
/O.CON.KGSP.FF.W.0003.000000T0000Z-210331T1900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Macon NC-
206 PM EDT Wed Mar 31 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 3 PM EDT THIS 
AFTERNOON FOR SOUTHEASTERN MACON COUNTY...

At 206 PM EDT, Localized excessive runoff from this morning's very 
heavy rainfall continued to diminish and no reports of flooding had 
been received.  Based on this trend, the warning will expire on 
schedule.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3514 8330 3517 8324 3516 8321 3513 8319
      3511 8318 3509 8315 3508 8314 3507 8317
      3506 8317 3506 8316 3500 8311 3499 8347
      3500 8351 3500 8352 3501 8353 3507 8345
      3512 8343 3514 8342 3514 8340

FLASH FLOOD...RADAR INDICATED

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Mar 31, 4:25 AM EDT	Wind Advisory	GSP	Avery, Buncombe, Burke, Caldwell, Graham, Haywood and 11 more	43 hr
Mar 31, 9:04 AM EDT	Areal Flood Advisory	GSP	Macon	3 hr
Mar 31, 9:23 AM EDT	Areal Flood Advisory	GSP	Graham, Swain	3 hr
Mar 31, 9:41 AM EDT	Flash Flood Warning	GSP	Macon	5 hr
Mar 31, 10:14 AM EDT	Areal Flood Advisory	GSP	Jackson, Transylvania	3 hr
Mar 31, 10:33 AM EDT	Areal Flood Advisory	GSP	Transylvania	4 hr
Mar 31, 1:03 PM EDT	River Flood Advisory	GSP	Henderson, Transylvania	14 hr
Mar 31, 2:04 PM EDT	River Flood Advisory	GSP	Buncombe, Henderson	13 hr
Mar 31, 2:23 PM EDT	River Flood Advisory	GSP	Buncombe	13 hr
Mar 31, 2:59 PM EDT	Freeze Watch	GSP	Cabarrus, Cleveland, Gaston, Lincoln, Mecklenburg, Polk and 2 more	12 hr
Mar 31, 8:55 AM EDT	Areal Flood Advisory	GSP	Habersham, Rabun	3 hr

Nearby

Flash Flood Warnings in North Carolina, 2021 Flash Flood Warnings in Georgia, 2021 Every flash flood warning 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.