Alert archive / Pennsylvania / Flash Flood Warnings in 2012

Flash Flood Warning 13, NWS Pittsburgh, PA

September 27, 2012Allegheny County, Pennsylvania

NWS Pittsburgh, PA issued this flash flood warning at Sep 27, 2012, 5:43 PM EDT for Allegheny County, Pennsylvania. It was in force for 85 min. 2 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 27, 2012, 5:43 PM EDT (21:43 UTC)
Expired
Sep 27, 2012, 7:08 PM EDT
In force
85 min
Issued by
NWS Pittsburgh, PA
Area
Storm-based polygon
Flood severity
None

County Allegheny County, PA

The radar

The Pittsburgh radar (KPBZ), 36 km from the middle of the area, began a volume at 21:44 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 27, 5:55 PM EDTFLASH FLOODPittsburgh, PA10 INCHES OF WATER ON NADINE ROAD
Sep 27, 6:15 PM EDTFLASH FLOODAspinwall, PAROADWAY BUCKLING DUE TO RAIN ON CENTER AVE

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

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 12:00Z, 9.7 hours before the alert went out and 26 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, Pittsburgh, PA at 12:00Z on 2012-09-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLEL10008507005003002001001 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, Pittsburgh, PA at 12:00Z on 2012-09-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 36 square meters per square second.193958Sfc1 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
2 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
523 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
36 m²/s²
0-3 km storm-relative helicity
75 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

The text

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

773 
WGUS51 KPBZ 272143
FFWPBZ
PAC003-272345-
/O.NEW.KPBZ.FF.W.0013.120927T2143Z-120927T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE PITTSBURGH PA
543 PM EDT THU SEP 27 2012

THE NATIONAL WEATHER SERVICE IN PITTSBURGH HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL ALLEGHENY COUNTY IN SOUTHWEST PENNSYLVANIA...

* UNTIL 745 PM EDT

* AT 540 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM NEAR DOWNTOWN PITTSBURGH...
  MOVING EAST AT 20 MPH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLOODING IS OCCURRING OR IS IMMINENT. MOST FLOOD RELATED DEATHS OCCUR
IN AUTOMOBILES...SO DO NOT CROSS WATER COVERED BRIDGES...DIPS...OR
LOW WATER CROSSINGS. NEVER TRY TO CROSS A FLOWING STREAM...EVEN A
SMALL ONE...ON FOOT. MOVE UP TO HIGHER GROUND.

PLEASE REPORT HIGH WATER TO THE NATIONAL WEATHER SERVICE BY CALLING
TOLL FREE...1-877-633-6772.

&&

LAT...LON 4042 7971 4039 7975 4039 7976 4035 7978
      4040 8009 4053 8009 4058 7977 4055 7977
      4054 7972 4053 7970

$$
3 follow-up statements
641 
WGUS71 KPBZ 272150
FFSPBZ

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
550 PM EDT THU SEP 27 2012

PAC003-272345-
/O.CON.KPBZ.FF.W.0013.000000T0000Z-120927T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
ALLEGHENY PA-
550 PM EDT THU SEP 27 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 745 PM EDT FOR
ALLEGHENY COUNTY...

AT 544 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE SHOWERS AND ISOLATED THUNDERSTORMS PRODUCING VERY HEAVY 
RAIN.  THE LEADING EDGE OF THIS RAIN AREA WAS LOCATED ALONG A LINE 
EXTENDING FROM PENN HILLS TO SOUTH SIDE PITTSBURGH...MOVING EAST AT 
25 MPH.  EXPECT A RAIN TOTAL OF ONE TO TWO INCHES.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
SPRINGDALE...WILKINSBURG...PLUM...WEST MIFFLIN...TURTLE CREEK AND 
MONROEVILLE.

FLOODING HAS ALREADY BEEN REPORTED IN BALDWIN...CLARION...AND 
WILKINS TOWNSHIP.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLOODING IS OCCURRING OR IS IMMINENT. MOST FLOOD RELATED DEATHS OCCUR
IN AUTOMOBILES...SO DO NOT CROSS WATER COVERED BRIDGES...DIPS...OR
LOW WATER CROSSINGS. NEVER TRY TO CROSS A FLOWING STREAM...EVEN A
SMALL ONE...ON FOOT. MOVE UP TO HIGHER GROUND.

PLEASE REPORT HIGH WATER TO THE NATIONAL WEATHER SERVICE BY CALLING
TOLL FREE...1-877-633-6772.

&&

LAT...LON 4042 7971 4039 7975 4039 7976 4035 7978
      4040 8009 4053 8009 4058 7977 4055 7977
      4054 7972 4053 7970

$$

15
832 
WGUS71 KPBZ 272223
FFSPBZ

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
623 PM EDT THU SEP 27 2012

PAC003-272345-
/O.CON.KPBZ.FF.W.0013.000000T0000Z-120927T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
ALLEGHENY PA-
623 PM EDT THU SEP 27 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 745 PM EDT FOR
ALLEGHENY COUNTY...

AT 619 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THAT HEAVY RAIN HAD EXITED ALLEGHENY COUNTY.  HOWEVER...RUNOFF FROM 
THE RAIN WILL CONTINUE FOR A COUPLE HOURS.  NUMEROUS REPORTS OF 
FLOODING IN POOR DRAINAGE AREAS...AND IN AREAS WHERE STORM DRAINS 
WERE CLOGGED WERE RECEIVED.  WATER WILL CONTINUE TO SLOWLY DRAIN AS 
THE EVENING PROGRESSES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD RELATED DEATHS OCCUR IN AUTOMOBILES...SO DO NOT CROSS 
WATER COVERED BRIDGES...DIPS...OR LOW WATER CROSSINGS. NEVER TRY TO 
CROSS A FLOWING STREAM...EVEN A SMALL ONE...ON FOOT. MOVE UP TO 
HIGHER GROUND.

PLEASE REPORT HIGH WATER TO THE NATIONAL WEATHER SERVICE BY CALLING
TOLL FREE...1-877-633-6772.

&&

LAT...LON 4042 7971 4039 7975 4039 7976 4035 7978
      4040 8009 4053 8009 4058 7977 4055 7977
      4054 7972 4053 7970

$$

15
341 
WGUS71 KPBZ 272308
FFSPBZ

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE PITTSBURGH PA
708 PM EDT THU SEP 27 2012

PAC003-272317-
/O.CAN.KPBZ.FF.W.0013.000000T0000Z-120927T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
ALLEGHENY PA-
708 PM EDT THU SEP 27 2012

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR ALLEGHENY COUNTY...

THE THREAT OF HEAVY RAINFALL HAS ENDED AND MUCH OF THE PONDED WATER 
HAS RUN OFF.  SO...THE NATIONAL WEATHER HAS CANCELLED THE FLASH 
FLOOD WARNING.  A FLOOD ADVISORY REMAINS IN EFFECT FOR RESIDUAL 
RUNOFF INTO POOR DRAINAGE AREAS.

PLEASE REPORT HIGH WATER TO THE NATIONAL WEATHER SERVICE BY CALLING
TOLL FREE...1-877-633-6772.

LAT...LON 4042 7971 4039 7975 4039 7976 4035 7978
      4040 8009 4053 8009 4058 7977 4055 7977
      4054 7972 4053 7970

$$

15

The office that day

Everything else NWS Pittsburgh, PA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 27, 4:54 PM EDTSpecial Weather StatementPBZAllegheny36 min
Sep 27, 5:08 PM EDTSpecial Weather StatementPBZAllegheny, Beaver, Washington, Westmoreland52 min
Sep 27, 5:11 PM EDTSpecial Weather StatementPBZAllegheny, Westmoreland49 min
Sep 27, 5:17 PM EDTAreal Flood AdvisoryPBZAllegheny2 hr
Sep 27, 6:08 PM EDTSpecial Weather StatementPBZIndiana52 min

Nearby

Flash Flood Warnings in Pennsylvania, 2012Every 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.