Alert archive / North Carolina / Flash Flood Warnings in 2012

Flash Flood Warning 38, NWS Raleigh, NC

August 28, 2012Forsyth County, Guilford County, North Carolina

NWS Raleigh, NC issued this flash flood warning at Aug 28, 2012, 9:10 PM EDT for Forsyth County, Guilford County, North Carolina. It was in force for 3 hr. 7 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: Aug 28, 2012, 9:10 PM EDT (01:10 UTC)
Expired: Aug 29, 2012, 12:00 AM EDT
In force: 3 hr
Issued by: NWS Raleigh, NC
Area: Storm-based polygon
Flood severity: None

Counties Forsyth County, NC, Guilford County, NC

The radar

The Roanoke radar (KFCX), 107 km from the middle of the area, began a volume at 01:13 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
Aug 28, 9:31 PM EDT	FLASH FLOOD	2 Ene Winston-Salem, NC	ROAD CLOSED DUE TO FLOODING AT CLEVELAND AVE. AND 15TH ST.
Aug 28, 9:31 PM EDT	FLASH FLOOD	2 Ne Winston-Salem, NC	ROAD CLOSED DUE TO FLOODING AT THE 2800 BLOCK OF LIBERTY ST.
Aug 28, 9:31 PM EDT	FLASH FLOOD	2 N Winston-Salem, NC	ROAD CLOSED DUE TO FLOODING AT THE 2800 BLOCK OF UNIVERSITY PARKWAY.
Aug 28, 9:49 PM EDT	FLASH FLOOD	Winston-Salem, NC	ACTIVE WATER RESCUE FOR MULTIPLE SUBJECTS TRAPPED IN A VEHICLE AT NORTHWEST BLVD AND THURMOND ST. IN WINSTON SALEM.
Aug 28, 10:25 PM EDT	HEAVY RAIN 3.36	4 N Lewisville, NC	3.36 INCHES OF RAIN FELL IN AN HOUR AND 45 MIN.
Aug 28, 10:50 PM EDT	HEAVY RAIN 3.29	Smith Reynolds Apt, NC	3.29 INCHES OF RAIN FELL IN THE PAST 2 HOURS.
Aug 28, 11:55 PM EDT	FLASH FLOOD	Winston-Salem, NC	FLOOD WATERS HAVE RECEDED.

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

The nearest sounding before it

Greensboro/Hi Pt, NC (KGSO), launched 00:00Z, 1.2 hours before the alert went out and 30 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: 2163 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 766 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 59 m²/s²
0-3 km storm-relative helicity: 61 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 3.7

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

498 
WGUS52 KRAH 290110
FFWRAH
NCC067-081-290400-
/O.NEW.KRAH.FF.W.0038.120829T0110Z-120829T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE RALEIGH NC
910 PM EDT TUE AUG 28 2012

THE NATIONAL WEATHER SERVICE IN RALEIGH HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  FORSYTH COUNTY IN CENTRAL NORTH CAROLINA
  GUILFORD COUNTY IN CENTRAL NORTH CAROLINA

* UNTIL MIDNIGHT EDT

* AT 906 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
SLOW MOVING THUNDERSTORMS PRODUCING RAINFALL RATES IN EXCESS OF 2 
INCHES PER HOUR OVER A HIGHLY URBAN AREA INCLUDING WINSTON-SALEM AND 
AND GREENSBORO. THE WINSTON-SALEM OBSERVATION REPORTED NEARLY 0.50 
OF AN INCH OF RAIN IN LESS THAN 15 MINUTES. THESE RAINFALL RATES 
OVER URBAN AREAS WILL PRODUCE FLOODING IN WINSTON-SALEM AND 
GREENSBORO... AS WELL AS SURROUNDING AREAS. 

* LOCATIONS THREATENED WITH FLOODING INCLUDE WINSTON-SALEM...
  KERNERSVILLE...CLEMMONS...MCLEANSVILLE...HIGH POINT AND GREENSBORO.

THIS LINE OF THUNDERSTORMS WITH VERY HEAVY RAIN WILL SLOWLY MOVE 
SOUTH THROUGH THE REGION. 1 TO LOCALLY 3 INCHES OF RAIN IN AN HOUR 
WILL PRODUCE FLASH FLOODING. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODS AND FLASH FLOODS. IF FLASH FLOODING IS OBSERVED ACT
QUICKLY. MOVE UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY
IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

PLEASE REPORT FLOODING TO THE NATIONAL WEATHER SERVICE BY CALLING...
1...8 7 7...6 3 3...6 7 7 2 OR NOTIFY YOUR LOCAL LAW ENFORCEMENT
AGENCY.

&&

LAT...LON 3614 8044 3622 8044 3626 8045 3623 7953
      3590 7955 3592 8004 3601 8004 3603 8013
      3603 8021 3600 8022 3600 8032 3597 8040
      3599 8043 3601 8042 3605 8047 3612 8046

$$

BADGETT

2 follow-up statements

494 
WGUS72 KRAH 290209
FFSRAH

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
1009 PM EDT TUE AUG 28 2012

NCC067-081-290400-
/O.CON.KRAH.FF.W.0038.000000T0000Z-120829T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FORSYTH NC-GUILFORD NC-
1009 PM EDT TUE AUG 28 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL MIDNIGHT EDT FOR 
FORSYTH AND GUILFORD COUNTIES...

AT 1004 PM EDT...NATIONAL WEATHER SERVICE RADAR CONTINUED TO 
INDICATE SLOW MOVING THUNDERSTORMS WITH HEAVY RAIN ACROSS FORSYTH 
AND NORTHERN GUILFORD COUNTIES... MOVING SLOWLY SOUTHEAST AT 15 
MPH. 

WEATHER SPOTTERS REPORTED FLOODING IN LEWISVILLE WHERE 2.09 INCHES 
OF RAIN HAD FALLEN SINCE 845 PM. THE WINSTON-SALEM AIRPORT REPORTED 
2.64 INCHES OF RAIN IN 50 MINUTES BETWEEN 900 PM AND 950 PM. THESE 
RAINFALL RATES AND RESULTANT AMOUNTS WERE PRODUCING FLASH FLOODING 
IN A HIGHLY URBAN REGION AROUND WINSTON-SALEM. 

LOCATIONS THREATENED BY FLOODING INCLUDE BUT ARE NOT LIMITED TO 
WINSTON-SALEM...CLEMMONS... LEWISVILLE... KERNERSVILLE... GREENSBORO.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE 
DANGERS OF FLOODING. ABSOLUTELY DO NOT DRIVE THROUGH WATER OF 
UNKNOWN DEPTH. TURN AROUND DONT DROWN. 

PLEASE REPORT FLOODING TO THE NATIONAL WEATHER SERVICE BY CALLING...
1...8 7 7...6 3 3...6 7 7 2 OR NOTIFY YOUR LOCAL LAW ENFORCEMENT
AGENCY.

&&

LAT...LON 3614 8044 3622 8044 3626 8045 3623 7953
      3590 7955 3592 8004 3601 8004 3603 8013
      3603 8021 3600 8022 3600 8032 3597 8040
      3599 8043 3601 8042 3605 8047 3612 8046

$$

BADGETT

050 
WGUS72 KRAH 290358
FFSRAH

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
1158 PM EDT TUE AUG 28 2012

NCC067-081-290406-
/O.EXP.KRAH.FF.W.0038.000000T0000Z-120829T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
FORSYTH NC-GUILFORD NC-
1158 PM EDT TUE AUG 28 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT MIDNIGHT EDT FOR GUILFORD
AND FORSYTH COUNTIES...

THE HEAVY RAIN HAS MOVED OUT OF THE AREA AND ALL ROADS HAVE BEEN 
REOPENED...THEREFORE THE FLOODING THREAT HAS ENDED.

LAT...LON 3614 8044 3622 8044 3626 8045 3623 7953
      3590 7955 3592 8004 3601 8004 3603 8013
      3603 8021 3600 8022 3600 8032 3597 8040
      3599 8043 3601 8042 3605 8047 3612 8046

$$

KRR

The office that day

Everything else NWS Raleigh, NC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 28, 8:00 PM EDT	Special Weather Statement	RAH	Granville, Vance, Warren	60 min
Aug 28, 8:41 PM EDT	Special Weather Statement	RAH	Alamance, Durham, Forsyth, Franklin, Granville, Guilford and 4 more	2 hr
Aug 28, 9:01 PM EDT	Areal Flood Advisory	RAH	Alamance, Forsyth, Guilford	3 hr
Aug 28, 9:48 PM EDT	Areal Flood Advisory	RAH	Durham, Granville	102 min
Aug 29, 2:28 PM EDT	Areal Flood Advisory	RAH	Anson	2 hr
Aug 29, 2:51 PM EDT	Areal Flood Advisory	RAH	Richmond, Scotland	2 hr
Aug 29, 5:21 PM EDT	Areal Flood Advisory	RAH	Cumberland	99 min
Aug 29, 5:43 PM EDT	Flash Flood Warning	RAH	Cumberland	3 hr

Nearby

Flash Flood Warnings in North Carolina, 2012 Every flash flood warning in 2012

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.