Alert archive / Pennsylvania / Flash Flood Warnings in 2011

Flash Flood Warning 65, NWS Philadelphia/Mount Holly

September 23, 2011Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 23, 2011, 12:47 PM EDT for Philadelphia County, Pennsylvania. It was in force for 2 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: Sep 23, 2011, 12:47 PM EDT (16:47 UTC)
Expired: Sep 23, 2011, 2:50 PM EDT
In force: 2 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 56 km from the middle of the area, began a volume at 16:51 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

Brookhaven, NY (KOKX), launched 12:00Z, 4.8 hours before the alert went out and 205 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: 454 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 434 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 53 m²/s²
0-3 km storm-relative helicity: 90 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.0

Open this sounding in Storm Lab

The text

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

558 
WGUS51 KPHI 231647
FFWPHI
PAC101-231945-
/O.NEW.KPHI.FF.W.0065.110923T1647Z-110923T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1247 PM EDT FRI SEP 23 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHEASTERN PHILADELPHIA COUNTY...

* UNTIL 345 PM EDT...

* AT 1239 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR AND RAIN   
  GAGES INDICATED THAT AN INCH OF RAIN HAS QUICKLY FALLEN ACROSS     
  PORTIONS OF THE COUNTY. IN RESPONSE, THE PENNYPACK CREEK AND       
  FRANKFORD CREEK ARE RISING RAPIDLY AND ARE EXPECTED TO OVERFLOW.   

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO RURAL AREAS
  OF NORTHEASTERN PHILADELPHIA COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PLEASE REPORT FLOODING...HAIL OR WIND DAMAGE TO THE NATIONAL WEATHER
SERVICE BY CALLING TOLL FREE...1-877-633-6772.

&&

LAT...LON 4004 7499 4003 7499 4001 7504 3998 7508
      4007 7518 4007 7517 4005 7512 4010 7507
      4013 7502 4013 7500 4011 7496 4008 7497

$$

KRUZDLO

1 follow-up statement

318 
WGUS71 KPHI 231850
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
250 PM EDT FRI SEP 23 2011

PAC101-231900-
/O.CAN.KPHI.FF.W.0065.000000T0000Z-110923T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PHILADELPHIA PA-
250 PM EDT FRI SEP 23 2011

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR NORTHEASTERN
PHILADELPHIA COUNTY...

THE WATERS FROM THE EARLIER HEAVY RAINS HAVE RECEDED AND FLOOD WATERS
NO LONGER POSE A THREAT TO LIFE OR PROPERTY. THEREFORE...THE FLASH
FLOOD WARNING HAS BEEN CANCELLED.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO RURAL AREAS
OF NORTHEASTERN PHILADELPHIA COUNTY.

LAT...LON 4004 7499 4003 7499 4001 7504 3998 7508
      4007 7518 4007 7517 4005 7512 4010 7507
      4013 7502 4013 7500 4011 7496 4008 7497

$$

KRUZDLO

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 23, 10:13 AM EDT	Areal Flood Advisory	PHI	Chester, Delaware	5 hr
Sep 23, 10:52 AM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery, Philadelphia	5 hr
Sep 23, 11:49 AM EDT	Areal Flood Advisory	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	6 hr
Sep 23, 1:59 PM EDT	Areal Flood Warning	PHI	Carbon	3 hr
Sep 23, 5:27 PM EDT	Areal Flood Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	12 hr
Sep 23, 5:53 PM EDT	Areal Flood Warning	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	12 hr
Sep 23, 6:34 PM EDT	Areal Flood Warning	PHI	Bucks	4 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2011 Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.