Alert archive / Pennsylvania / Areal Flood Warnings in 2011

Areal Flood Warning 72, NWS Philadelphia/Mount Holly

September 6, 2011Montgomery County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this areal flood warning at Sep 6, 2011, 6:38 PM EDT for Montgomery County, Philadelphia County, Pennsylvania. It was in force for 23 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 6, 2011, 6:38 PM EDT (22:38 UTC)
Expired: Sep 7, 2011, 5:58 PM EDT
In force: 23 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 74 km from the middle of the area, began a volume at 22:39 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

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 10.6 hours before the alert went out and 97 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 739 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 63 m²/s²
0-3 km storm-relative helicity: 555 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

858 
WGUS41 KPHI 062238
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
638 PM EDT TUE SEP 6 2011

PAC091-101-070430-
/O.NEW.KPHI.FA.W.0072.110906T2238Z-110907T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PHILADELPHIA PA-MONTGOMERY PA-
638 PM EDT TUE SEP 6 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS IN...
  WESTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 1230 AM EDT

* AT 636 PM EDT...THE WISSAHICKON CREEK IN PHILADELPHIA WAS AT 4.6 
  FEET. FLOOD STAGE IS 5.0 FEET. ADDITIONAL RAIN THIS EVENING WILL 
  PUSH THE CREEK OVER FLOOD STAGE.

* THE WISSAHICKON CREEK AT FORT WASHINGTON WAS AT 7.5 FEET. FLOOD STAGE
  IS 9.0 FEET. ADDITIONAL RAIN WILL PUSH THE CREEK ABOVE FLOOD STAGE.

A FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR HAS BEEN REPORTED.
STREAM RISES WILL BE SLOW AND FLASH FLOODING IS NOT EXPECTED.
HOWEVER...ALL INTERESTED PARTIES SHOULD TAKE NECESSARY PRECAUTIONS
IMMEDIATELY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE ELEVATED LEVELS ON
SMALL CREEKS AND STREAMS...AND PONDING OF WATER IN URBAN AREAS...
HIGHWAYS...STREETS AND UNDERPASSES AS WELL AS OTHER POOR DRAINAGE
AREAS AND LOW LYING SPOTS.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF 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 4006 7513 3989 7516 3986 7522 3996 7525
      4004 7535 4007 7537 4007 7540 4018 7553
      4031 7531 4014 7503

$$

HAYES/PIETRAFESA

6 follow-up statements

956 
WGUS41 KPHI 070423
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1223 AM EDT WED SEP 7 2011

PAC091-101-070730-
/O.EXT.KPHI.FA.W.0072.000000T0000Z-110907T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PHILADELPHIA PA-MONTGOMERY PA-
1223 AM EDT WED SEP 7 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS EXTENDED THE

* FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS IN...
  WESTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 330 AM EDT

* AT 1221 AM EDT...SOME SMALL STREAMS IN THE AREA REMAIN OVER THEIR  
  BANKS. WHILE THE HEAVY RAIN HAS MOVED OUT OF THE AREA...THE AREAL  
  FLOOD WARNING REMAINS IN EFFECT UNTIL THESE STREAMS RECEDE BELOW   
  FLOOD STAGE.

A FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR HAS BEEN REPORTED.
STREAM RISES WILL BE SLOW AND FLASH FLOODING IS NOT EXPECTED.
HOWEVER...ALL INTERESTED PARTIES SHOULD TAKE NECESSARY PRECAUTIONS
IMMEDIATELY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE ELEVATED LEVELS ON
SMALL CREEKS AND STREAMS...AND PONDING OF WATER IN URBAN AREAS...
HIGHWAYS...STREETS AND UNDERPASSES AS WELL AS OTHER POOR DRAINAGE
AREAS AND LOW LYING SPOTS.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE ELEVATED LEVELS ON
SMALL CREEKS AND STREAMS...AND PONDING OF WATER ON COUNTRY ROADS AND
FARMLAND ALONG THE BANKS OF CREEKS AND STREAMS.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF 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 4006 7513 3989 7516 3986 7522 3996 7525
      4004 7535 4007 7537 4007 7540 4018 7553
      4031 7531 4014 7503

$$

JJM

562 
WGUS41 KPHI 070716
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
316 AM EDT WED SEP 7 2011

PAC091-101-071330-
/O.EXT.KPHI.FA.W.0072.000000T0000Z-110907T1330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PHILADELPHIA PA-MONTGOMERY PA-
316 AM EDT WED SEP 7 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS EXTENDED THE

* FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS IN...
  WESTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 930 AM EDT

* AT 313 AM EDT SMALL STREAMS IN THE AREA WERE STILL RUNNING HIGH    
  FROM EARLIER RAIN. DOPPLER RADAR INDICATED ANOTHER LINE OF SHOWERS 
  MOVING IN FROM THE SOUTH. THE AREAL FLOOD WARNING HAS THEREFORE    
  BEEN EXTENDED UNTIL 930 AM EDT.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE ELEVATED LEVELS ON
SMALL CREEKS AND STREAMS...AND PONDING OF WATER IN URBAN AREAS...
HIGHWAYS...STREETS AND UNDERPASSES AS WELL AS OTHER POOR DRAINAGE
AREAS AND LOW LYING SPOTS.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF 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 4006 7513 3989 7516 3986 7522 3996 7525
      4004 7535 4007 7537 4007 7540 4018 7553
      4031 7531 4014 7503

$$

JJM

516 
WGUS41 KPHI 071228
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
828 AM EDT WED SEP 7 2011

PAC091-101-071930-
/O.EXT.KPHI.FA.W.0072.000000T0000Z-110907T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PHILADELPHIA PA-MONTGOMERY PA-
828 AM EDT WED SEP 7 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS EXTENDED THE

* FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS IN...
  WESTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 330 PM EDT WEDNESDAY

* AT 825 AM EDT...SMALL STREAM FLOODING CONTINUED ACROSS PORTIONS OF 
THE WARNED AREA. THE WATER LEVEL ON THE WISSAHICKON CREEK IN 
PHILADELPHIA WAS AT 5.23 FEET AND WAS RISING. FLOOD STAGE IS 5.0 
FEET. AT FORT WASHINGTON...THE WATER LEVEL WAS 10.80 FEET. FLOOD 
STAGE IS 9.0 FEET.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE ELEVATED LEVELS ON
SMALL CREEKS AND STREAMS...AND PONDING OF WATER IN URBAN AREAS...
HIGHWAYS...STREETS AND UNDERPASSES AS WELL AS OTHER POOR DRAINAGE
AREAS AND LOW LYING SPOTS.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE 
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS 
SAFELY. MOVE TO HIGHER GROUND.

&&

LAT...LON 4006 7513 3989 7516 3986 7522 3996 7525
      4004 7535 4007 7537 4007 7540 4018 7553
      4031 7531 4014 7503

$$

KRUZDLO

419 
WGUS81 KPHI 071730
FLSPHI

FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
130 PM EDT WED SEP 7 2011

PAC091-071737-
/O.CAN.KPHI.FA.W.0072.000000T0000Z-110907T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MONTGOMERY PA-
130 PM EDT WED SEP 7 2011

...THE FLOOD WARNING HAS BEEN CANCELLED FOR URBAN AREAS AND SMALL
STREAMS IN MONTGOMERY COUNTY...

LAT...LON 3989 7516 3986 7522 3996 7525 3998 7528
      4001 7522 4005 7527 4009 7523 4007 7520
      4008 7517 4005 7513

$$

PAC101-071930-
/O.CON.KPHI.FA.W.0072.000000T0000Z-110907T1930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PHILADELPHIA PA-
130 PM EDT WED SEP 7 2011

...THE FLOOD WARNING REMAINS IN EFFECT UNTIL 330 PM EDT FOR URBAN
AREAS AND SMALL STREAMS IN WESTERN PHILADELPHIA COUNTY...

AT 127 PM EDT...SMALL STREAM FLOODING CONTINUED ACROSS PORTIONS OF 
THE WARNED AREA. THE WATER LEVEL AT THE PHILADELPHIA WISSAHICKON 
CREEK GAGE WAS 6.18 FEET AND WAS FALLING. FLOOD STAGE IS 5.0 FEET.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE ELEVATED LEVELS ON
SMALL CREEKS AND STREAMS...AND PONDING OF WATER IN URBAN AREAS...
HIGHWAYS...STREETS AND UNDERPASSES AS WELL AS OTHER POOR DRAINAGE
AREAS AND LOW LYING SPOTS.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE 
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS 
SAFELY. MOVE TO HIGHER GROUND.

&&

LAT...LON 3989 7516 3986 7522 3996 7525 3998 7528
      4001 7522 4005 7527 4009 7523 4007 7520
      4008 7517 4005 7513

$$

KRUZDLO

692 
WGUS41 KPHI 071732
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
132 PM EDT WED SEP 7 2011

PAC101-080130-
/O.EXT.KPHI.FA.W.0072.000000T0000Z-110908T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PHILADELPHIA PA-
132 PM EDT WED SEP 7 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS EXTENDED THE

* FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS IN...
  WESTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 930 PM EDT

* AT 132 PM EDT...SMALL STREAM FLOODING CONTINUED ACROSS PORTIONS OF 
THE WARNED AREA. THE WATER LEVEL AT THE PHILADELPHIA WISSAHICKON 
CREEK GAGE WAS 6.18 FEET AND WAS FALLING. FLOOD STAGE IS 5.0 FEET. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE ELEVATED LEVELS ON
SMALL CREEKS AND STREAMS...AND PONDING OF WATER IN URBAN AREAS...
HIGHWAYS...STREETS AND UNDERPASSES AS WELL AS OTHER POOR DRAINAGE
AREAS AND LOW LYING SPOTS.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE 
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS 
SAFELY. MOVE TO HIGHER GROUND.

&&

LAT...LON 3989 7516 3986 7522 3996 7525 3998 7528
      4001 7522 4005 7527 4009 7523 4007 7520
      4008 7517 4005 7513

$$

KRUZDLO

708 
WGUS81 KPHI 072158
FLSPHI

FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
558 PM EDT WED SEP 7 2011

PAC101-072207-
/O.CAN.KPHI.FA.W.0072.000000T0000Z-110908T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PHILADELPHIA PA-
558 PM EDT WED SEP 7 2011

...THE FLOOD WARNING HAS BEEN CANCELLED FOR URBAN AREAS AND SMALL
STREAMS IN WESTERN PHILADELPHIA COUNTY...

THE WATER LEVEL AT THE PHILADELPHIA WISSAHICKON CREEK HAS DROPPED 
BELOW FLOOD STAGE...AND CONTINUES TO FALL.

LAT...LON 3989 7516 3986 7522 3996 7525 3998 7528
      4001 7522 4005 7527 4009 7523 4007 7520
      4008 7517 4005 7513

$$

HAYES

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 5, 8:19 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Lehigh, Montgomery, Northampton	116 min
Sep 5, 9:32 PM EDT	Areal Flood Warning	PHI	Montgomery	9 hr
Sep 5, 10:18 PM EDT	Flash Flood Warning	PHI	Lehigh, Northampton	4 hr
Sep 5, 10:53 PM EDT	Areal Flood Advisory	PHI	Chester, Montgomery	3 hr
Sep 5, 11:04 PM EDT	Areal Flood Advisory	PHI	Bucks	6 hr
Sep 5, 11:25 PM EDT	Flash Flood Warning	PHI	Berks	4 hr
Sep 6, 12:22 AM EDT	Areal Flood Advisory	PHI	Delaware, Philadelphia	3 hr
Sep 6, 1:42 AM EDT	Areal Flood Advisory	PHI	Chester, Montgomery	3 hr
Sep 6, 2:09 AM EDT	Areal Flood Advisory	PHI	Lehigh, Northampton	3 hr
Sep 6, 3:40 AM EDT	Areal Flood Warning	PHI	Berks	3 hr
Sep 6, 5:43 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	3 hr
Sep 6, 5:49 PM EDT	Areal Flood Warning	PHI	Philadelphia	20 hr
Sep 6, 6:10 PM EDT	Areal Flood Warning	PHI	Bucks, Monroe, Northampton	71 hr
Sep 6, 6:32 PM EDT	Areal Flood Warning	PHI	Montgomery	26 hr
Sep 6, 6:44 PM EDT	Areal Flood Warning	PHI	Chester, Delaware	15 hr
Sep 6, 6:48 PM EDT	Areal Flood Warning	PHI	Bucks	31 hr
Sep 6, 7:03 PM EDT	River Flood Warning	PHI	Chester	16 hr
Sep 6, 7:41 PM EDT	River Flood Warning	PHI	Delaware	5 hr
Sep 6, 7:52 PM EDT	River Flood Warning	PHI	Bucks	52 hr

Nearby

Areal Flood Warnings in Pennsylvania, 2011 Every areal 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.