Alert archive / North Carolina / Flash Flood Warnings in 2011

Flash Flood Warning 48, NWS Raleigh, NC

September 21, 2011Wake County, North Carolina

NWS Raleigh, NC issued this flash flood warning at Sep 21, 2011, 9:03 PM EDT for Wake 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
Sep 21, 2011, 9:03 PM EDT (01:03 UTC)
Expired
Sep 21, 2011, 11:46 PM EDT
In force
3 hr
Issued by
NWS Raleigh, NC
Area
Storm-based polygon
Flood severity
None

County Wake County, NC

The radar

The Raleigh/Durham radar (KRAX), 20 km from the middle of the area, began a volume at 01:05 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
Sep 21, 9:10 PM EDTHEAVY RAIN 2.513 Wsw Raleigh, NC2.51 INCHES OF RAIN MEASURED IN 1.5 HOURS AT RIDGE ROAD AND WADE AVENUE
Sep 21, 9:50 PM EDTFLASH FLOOD4 Sw Raleigh, NCAVENT FERRY BLOCKED AT TRAILWOOD DUE TO FLOODING
Sep 21, 9:50 PM EDTFLASH FLOOD4 Wsw Raleigh, NCBLUE RIDGE ROAD AT WESTERN BLVD WAS BLOCKED DUE TO FLOODING
Sep 21, 9:50 PM EDTFLASH FLOOD5 E Cary, NCHILLSBORO STREET WAS BLOCKED OFF AT THE RAILROAD CROSSING NEAR THE CHAPEL HILL ROAD SPLIT
Sep 21, 9:54 PM EDTHEAVY RAIN 2.282 Sw Holly Springs, NC2.28 INCHES OF RAIN OBSERVED IN 1.5 HOURS
Sep 21, 10:15 PM EDTFLASH FLOOD3 Nne Raleigh, NCTHREE FEET OF WATER ON OLD WAKE FOREST ROAD WITH VEHICHLE STUCK
Sep 21, 10:20 PM EDTFLASH FLOOD3 Nw New Hope, NCVEHICLE STUCK IN FLOODING AT MILBROOK ROAD AND HOYLE DRIVE

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, 1.1 hours before the alert went out and 125 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, Greensboro/Hi Pt, NC at 00:00Z on 2011-09-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 515 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Greensboro/Hi Pt, NC at 00:00Z on 2011-09-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 28 square meters per square second.19395878Sfc1 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
515 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
576 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
28 m²/s²
0-3 km storm-relative helicity
86 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.9

Open this sounding in Storm Lab

The text

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

417 
WGUS52 KRAH 220103
FFWRAH
NCC183-220400-
/O.NEW.KRAH.FF.W.0048.110922T0103Z-110922T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE RALEIGH NC
903 PM EDT WED SEP 21 2011

THE NATIONAL WEATHER SERVICE IN RALEIGH HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WAKE COUNTY IN CENTRAL NORTH CAROLINA

* UNTIL MIDNIGHT EDT

* AT 903 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  THUNDERSTORMS THAT WERE CONTINUOUSLY REDEVELOPING AND PRODUCING    
  VERY HEAVY RAINFALL OVER WAKE COUNTY... FROM HOLLY SPRINGS TO      
  RALEIGH AND WAKE FOREST. NATIONAL WEATHER SERVICE RADAR INDICATED  
  RAINFALL RATES IN EXCESS OF 2 INCHES PER HOUR WITH THESE STORMS.   
  THE THUNDERSTORMS WITH THE HEAVIEST RAIN AT 900 PM WERE OVER       
  RALEIGH AND BETWEEN HOLLY SPRINGS AND APEX... MOVING NORTHEAST AT  
  15 MPH. 

* LOCATIONS THREATENED WITH FLOODING INCLUDE WAKE FOREST...RALEIGH...
  GARNER...FUQUAY-VARINA AND CARY.

TRAINING OF THE THUNDERSTORMS WITH RAINFALL RATES IN EXCESS OF 2 
INCHES PER HOUR WILL RESULT IN FLASH FLOODING IN RALEIGH AND 
SURROUNDING AREAS. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TURN AROUND...DONT DROWN.

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.

&&

LAT...LON 3595 7840 3594 7839 3594 7838 3582 7826
      3555 7872 3561 7895 3579 7881 3602 7855

$$

BADGETT
3 follow-up statements
646 
WGUS72 KRAH 220138
FFSRAH

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
938 PM EDT WED SEP 21 2011

NCC183-220400-
/O.CON.KRAH.FF.W.0048.000000T0000Z-110922T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WAKE NC-
938 PM EDT WED SEP 21 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL MIDNIGHT EDT FOR
WAKE COUNTY...

AT 935 PM EDT...WEATHER SPOTTERS REPORTED THUNDERSTORMS WITH VERY 
HEAVY RAIN OVER RALEIGH AND MUCH OF CENTRAL AND EASTERN WAKE COUNTY. 
DOPPLER RADAR ESTIMATED THAT BETWEEN 2 AND 3 INCHES OF RAIN HAD 
FALLEN OVER AREAS FROM HOLLY SPRINGS TO RALEIGH SINCE 830 PM. 

WEATHER SPOTTERS REPORTED 1 TO 2 FEET OF WATER ON SEVERAL STREETS 
AROUND NORTH CAROLINA STATE UNIVERSITY AND FLOODING WAS OCCURRING IN 
DOWNTOWN RALEIGH. 

LOCATIONS THREATENED BY FLOODING INCLUDE BUT ARE NOT LIMITED TO 
RALEIGH... WAKE FOREST... KNIGHTDALE... WENDELL.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TURN AROUND...DONT DROWN.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. 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 3595 7840 3594 7839 3594 7838 3582 7826
      3555 7872 3561 7895 3579 7881 3602 7855

$$

BADGETT
741 
WGUS72 KRAH 220303
FFSRAH

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
1103 PM EDT WED SEP 21 2011

NCC183-220400-
/O.CON.KRAH.FF.W.0048.000000T0000Z-110922T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WAKE NC-
1103 PM EDT WED SEP 21 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL MIDNIGHT EDT FOR 
CENTRAL AND NORTHEASTERN WAKE COUNTY...

AT 1059 PM EDT...LOCAL LAW ENFORCEMENT REPORTED SEVERAL ROAD 
CLOSURES FROM WEST THROUGH DOWNTOWN AND NORTHEAST RALEIGH. THIS 
INCLUDED PORTIONS OF OLD WAKE FOREST ROAD... HODGES ROAD... ATLANTIC 
AVENUE... AVENT FERRY... LAKE BOONE TRAIL... AND WADE AVENUE. 
SEVERAL CARS STALLED IN THE FLOODING ON OLD WAKE FOREST ROAD AND 
HODGES AND THE CARS WERE ABANDONED. 

SINCE THE THE HEAVIEST RAIN HAS SHIFTED INTO FRANKLIN COUNTY... 
ADDITIONAL HEAVY RAIN IN THE NEXT FEW HOURS IS NOT ANTICIPATED. THE 
FLASH FLOODING IS EXPECTED TO SLOWLY RETREAT IN THE NEXT HOUR. THE 
WARNING SHOULD BE ALLOWED TO EXPIRE BARRING ADDITIONAL HEAVY RAIN. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE WATER COVERS THE ROAD. 
MANY ROADS AND INTERSECTIONS IN THE AREA WILL QUICKLY FLOOD. WHEN 
ENCOUNTERING FLOODED ROADS 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 3595 7841 3594 7839 3594 7838 3582 7826
      3573 7862 3577 7882 3602 7855

$$

BADGETT
628 
WGUS72 KRAH 220346
FFSRAH

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE RALEIGH NC
1146 PM EDT WED SEP 21 2011

NCC183-220350-
/O.CAN.KRAH.FF.W.0048.000000T0000Z-110922T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WAKE NC-
1146 PM EDT WED SEP 21 2011

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR CENTRAL AND 
NORTHEASTERN WAKE COUNTY...

NATIONAL WEATHER SERVICE RADAR INDICATED THAT THE SHOWERS AND 
THUNDERSTORMS WITH VERY HEAVY RAIN HAD SHIFTED WELL TO THE NORTHEAST 
OF THE REGION. ONLY LIGHT AND SCATTERED SHOWERS LINGERED OVER THE 
REGION. 

LOCAL LAW ENFORCEMENT INDICATED THAT THE PREVIOUS ROAD CLOSURES IN 
RALEIGH WERE NOW OPEN. THE FLOODING WAS RETREATING RAPIDLY EVEN 
ALONG CRABTREE CREEK AT OLD WAKE FOREST ROAD AND AT ATLANTIC 
AVENUE... JUST NORTH OF THE INTERSTATE 440 BELTLINE IN RALEIGH. 

SINCE HEAVY RAIN IS NOT EXPECTED TO REDEVELOP OVER THE AREA IN THE 
NEXT FEW HOURS... THE FLASH FLOODING WARNING WILL BE CANCELED.

LAT...LON 3595 7841 3594 7839 3594 7838 3582 7826
      3573 7862 3577 7882 3602 7855

$$

BADGETT

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 21, 8:43 PM EDTAreal Flood AdvisoryRAHWake3 hr
Sep 21, 9:50 PM EDTAreal Flood AdvisoryRAHChatham, Lee, Moore94 min
Sep 21, 10:37 PM EDTAreal Flood AdvisoryRAHFranklin, Nash104 min
Sep 22, 12:13 AM EDTSpecial Weather StatementRAHHalifax47 min
Sep 22, 3:31 PM EDTFlash Flood WatchRAHAlamance, Anson, Chatham, Davidson, Durham, Forsyth and 14 more24 hr

Nearby

Flash Flood Warnings in North Carolina, 2011Every flash flood warning in 2011

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.