Alert archive / Pennsylvania / Areal Flood Warnings in 2012

Areal Flood Warning 7, NWS Philadelphia/Mount Holly

May 27, 20125 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this areal flood warning at May 27, 2012, 10:07 AM EDT for 5 counties in Pennsylvania. It was in force for 3 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: May 27, 2012, 10:07 AM EDT (14:07 UTC)
Expired: May 27, 2012, 12:47 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Berks County, PA, Bucks County, PA, Lehigh County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 90 km from the middle of the area, began a volume at 14:11 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, 2.1 hours before the alert went out and 211 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: 1927 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: -27 m²/s²
0-3 km storm-relative helicity: 18 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.

880 
WGUS41 KPHI 271407
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1007 AM EDT SUN MAY 27 2012

PAC011-017-077-091-101-271700-
/O.NEW.KPHI.FA.W.0007.120527T1407Z-120527T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BERKS PA-BUCKS PA-LEHIGH PA-MONTGOMERY PA-PHILADELPHIA PA-
1007 AM EDT SUN MAY 27 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS IN...
  EAST CENTRAL BERKS COUNTY IN EASTERN PENNSYLVANIA...
  BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  SOUTHERN LEHIGH COUNTY IN EASTERN PENNSYLVANIA...
  NORTHERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHEASTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 100 PM EDT

* AT 959 AM EDT RADAR INDICATES CONTINUED REDEVELOPMENT OF HEAVY 
SHOWERS AND ISOLATED THUNDERSTORMS MOVING SOUTHEASTWARD FROM LEHIGH 
AND BERKS COUNTIES THROUGH BUCKS AND SOON THE NORTHERN PORTION OF 
MONTGOMERY COUNTIES IN SOUTHEAST PENNSYLVANIA. THIS WAS ACROSS 
SOME REGIONS SOAKED BY THUNDERSTORMS EARLIER THIS MORNING THAT 
PUSHED THE PERKIOMEN IN EAST GREENVILLE INTO MINOR FLOOD. THIS MAY 
AGAIN OCCUR BY NOON IF ANTICIPATED DEVELOPMENT SOUTHWARD OCCURS. 

* THIS WILL BE AN ACTIVE DAY WEATHERWISE WITH ISOLATED NEW RAINFALL 
BETWEEN NOW AND 1 PM EXPECTED TO RANGE BETWEEN 1 AND 2 INCHES. 
DOPPLER RADAR IS INDICATED AT LEAST 1 INCH HAS OCCURRED BETWEEN 9 AM 
AND 10 AM SOUTHEAST LEHIGH AND CENTRAL BUCKS COUNTIES.   

ADDITIONALLY...VISIBILITY IS REDUCED IN THE INTENSE RAINS TO LESS 
THAN A MILE AND SO CAUTION IS URGED WHEN TRAVELING. 

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 ISOLATED FLOODING OF 
SMALL CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. 
ADDITIONALLY...COUNTRY ROADS AND FARMLANDS ALONG THE BANKS OF 
CREEKS...STREAMS AND OTHER LOW LYING AREAS ARE SUBJECT TO POOR 
DRAINAGE FLOODING.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE.

&&

LAT...LON 4006 7495 4024 7537 4039 7565 4057 7566
      4062 7543 4060 7539 4057 7539 4054 7534
      4055 7531 4016 7473

$$

DRAG

4 follow-up statements

162 
WGUS81 KPHI 271442
FLSPHI

FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1042 AM EDT SUN MAY 27 2012

PAC011-017-077-091-101-271700-
/O.CON.KPHI.FA.W.0007.000000T0000Z-120527T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BERKS PA-BUCKS PA-LEHIGH PA-MONTGOMERY PA-PHILADELPHIA PA-
1042 AM EDT SUN MAY 27 2012

...THE FLOOD WARNING REMAINS IN EFFECT UNTIL 100 PM EDT FOR URBAN
AREAS AND SMALL STREAMS IN NORTHEASTERN PHILADELPHIA...NORTHERN
MONTGOMERY...SOUTHERN LEHIGH...BUCKS AND EAST CENTRAL BERKS
COUNTIES...

AT 1035 AM EDT CLUSTERS OF HEAVY SHOWERS AND THUNDERSTORMS CONTINUE 
TO MOVE SOUTHEAST AT 15 MILES AN HOUR FROM SOUTH OF ALLENTOWN IN 
SOUTHERN LEHIGH COUNTY THROUGH MUCH OF BUCKS INTO NORTHERN 
MONTGOMERY COUNTY BORDERING BUCKS IN PHILADELPHIA'S NORTHERN AND 
NORTHWEST SUBURBS. 

RAINFALL RATES CONTINUE TO BE INTENSE BENEATH THESE SLOW MOVING 
SHOWERS AND THUNDERSTORMS WITH VISIBILITY LESS THAN A MILE AND 
ISOLATED RAINFALL OF 1 TO 1.25 INCHES INDICATED BY DOPPLER RADAR.  

TRAVEL WILL BE VERY SLOW IN THESE SHOWERS. 

A FLOOD WARNING MEANS THAT FLOODING IS IMMINENT. SMALL STREAM RISES 
WILL BE QUICK. ALL INTERESTED PARTIES SHOULD TAKE NECESSARY 
PRECAUTIONS IMMEDIATELY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW
LYING AREAS ARE SUBJECT TO FLOODING.

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

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE.

&&

LAT...LON 4006 7495 4024 7537 4039 7565 4057 7566
      4062 7543 4060 7539 4057 7539 4054 7534
      4055 7531 4016 7473

$$

DRAG

909 
WGUS81 KPHI 271525
FLSPHI

FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1125 AM EDT SUN MAY 27 2012

PAC011-017-077-091-101-271700-
/O.CON.KPHI.FA.W.0007.000000T0000Z-120527T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BERKS PA-BUCKS PA-LEHIGH PA-MONTGOMERY PA-PHILADELPHIA PA-
1125 AM EDT SUN MAY 27 2012

...THE FLOOD WARNING REMAINS IN EFFECT UNTIL 100 PM EDT FOR URBAN
AREAS AND SMALL STREAMS IN NORTHEASTERN PHILADELPHIA...NORTHERN
MONTGOMERY...SOUTHERN LEHIGH...BUCKS AND EAST CENTRAL BERKS
COUNTIES...

AT 1119 AM EDT CLUSTERS OF MODERATE TO HEAVY SHOWERS CONTINUE TO 
REDEVELOP ALONG THE LEHIGH BUCKS COUNTY BORDER AND HEAD SOUTHEAST 
TOWARD DUBLIN AND DOYLESTOWN IN CENTRAL BUCKS COUNTY. 

FURTHER REDEVELOPMENT AND EXPANSION OF THE SHOWERS AND ISOLATED 
THUNDERSTORMS IS EXPECTED DURING THE MIDDAY HOURS. 

THE EAST BRANCH OF THE PERKIOMEN IN DUBLIN OF BUCKS COUNTY HAS RISEN 
1.5 FEET IN THE 45 MINUTES ENDING 11 AM AND ANTICIPATED ADDITIONAL 
RAINFALL BY NOON SHOULD PUSH THIS STREAM INTO FLOOD DURING MIDDAY.   

TRAVEL WILL BE SLOW IN THE HEAVIER RAINS WHICH REDUCE VISIBILITY AND 
THEIR WILL BE PONDING OF WATER ON ROADS.   

A FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR HAS BEEN REPORTED.
ALL INTERESTED PARTIES SHOULD TAKE NECESSARY PRECAUTIONS IMMEDIATELY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW
LYING AREAS ARE SUBJECT TO FLOODING.

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

&&

LAT...LON 4006 7495 4024 7537 4039 7565 4057 7566
      4062 7543 4060 7539 4057 7539 4054 7534
      4055 7531 4016 7473

$$

DRAG

472 
WGUS81 KPHI 271601
FLSPHI

FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1201 PM EDT SUN MAY 27 2012

PAC101-271605-
/O.CAN.KPHI.FA.W.0007.000000T0000Z-120527T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PHILADELPHIA PA-
1201 PM EDT SUN MAY 27 2012

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

LAT...LON 4016 7473 4012 7493 4024 7537 4039 7564
      4057 7556 4062 7543 4060 7539 4058 7540
      4054 7534 4055 7531

$$

PAC011-017-077-091-271700-
/O.CON.KPHI.FA.W.0007.000000T0000Z-120527T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BERKS PA-BUCKS PA-LEHIGH PA-MONTGOMERY PA-
1201 PM EDT SUN MAY 27 2012

...THE FLOOD WARNING REMAINS IN EFFECT UNTIL 100 PM EDT FOR URBAN
AREAS AND SMALL STREAMS IN NORTHERN MONTGOMERY...SOUTHEASTERN
LEHIGH...BUCKS AND EAST CENTRAL BERKS COUNTIES...

AT 1155 AM EDT THE AXIS OF THE MODERATE TO BRIEFLY HEAVY SHOWERS AND 
ISOLATED THUNDERSTORMS WAS SHIFTING NORTHEASTWARD...PRIMARILY INTO 
THE NORTHERN PORTION OF BUCKS COUNTY AND SOUTHERN PART OF LEHIGH 
COUNTY. 

HOWEVER...IT APPEARS THE RAINFALL IS RESULTING IN SOME SMALL STREAM 
FLOODING. THE EAST BRANCH PF THE PERKIOMEN AT 1145 AM WAS LESS THAN 
INCH FROM FLOOD AND IS EXPECTED TO CREST AT LEAST 2 OR 3 TENTHS OF A 
FOOT ABOVE FLOOD STAGE EARLY THIS AFTERNOON WITH MINOR SWIFT WATER 
FLOODING ALONG ITS BANKS.

SHOWERS AND THUNDERSTORMS REDEVELOP FURTHER SOUTHWEST DURING THE 
NOON HOUR AND THE WARNING HAS BEEN CONTINUED IN THOSE AREAS WHERE IT 
HAS NOT RAINED MUCH SINCE 11 AM. EVEN THERE...SOME SMALL STREAMS 
WERE RISING STEADILY.

A FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR HAS BEEN REPORTED.
ALL INTERESTED PARTIES SHOULD TAKE NECESSARY PRECAUTIONS IMMEDIATELY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4016 7473 4012 7493 4024 7537 4039 7564
      4057 7556 4062 7543 4060 7539 4058 7540
      4054 7534 4055 7531

$$

DRAG

487 
WGUS81 KPHI 271647
FLSPHI

FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1247 PM EDT SUN MAY 27 2012

PAC011-017-077-091-271652-
/O.CAN.KPHI.FA.W.0007.000000T0000Z-120527T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
MONTGOMERY PA-BERKS PA-LEHIGH PA-BUCKS PA-
1247 PM EDT SUN MAY 27 2012

...THE FLOOD WARNING HAS BEEN CANCELLED FOR URBAN AREAS AND SMALL
STREAMS IN BUCKS...SOUTHEASTERN LEHIGH...EAST CENTRAL BERKS AND
NORTHERN MONTGOMERY COUNTIES...

THE EAST BRANCH OF THE PERKIOMEN AT DUBLIN EXCEEDED ITS FLOOD STAGE 
OF 5.0 FEET AND REACHED 5.1 FEET AROUND 1145 AM. IT HAS SINCE FALLEN 
BACK BELOW FLOOD STAGE.

THERE MAY STILL BE POCKETS OF HIGH WATER IN SOME AREAS...SO DRIVERS 
SHOULD USE CAUTION.

ADDITIONAL RAINFALL IS POSSIBLE THROUGH THE AFTERNOON WHICH MAY 
CAUSE ADDITIONAL FLOODING.

LAT...LON 4016 7473 4012 7493 4024 7537 4039 7564
      4057 7556 4062 7543 4060 7539 4058 7540
      4054 7534 4055 7531

$$

ROBERTSON

The office that day

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

Issued	Product	Office	Counties	Lasted
May 27, 2:19 AM EDT	Special Weather Statement	PHI	Berks, Carbon, Lehigh, Montgomery, Northampton	56 min
May 27, 2:54 AM EDT	Special Weather Statement	PHI	Bucks	66 min
May 27, 3:10 AM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Lehigh, Montgomery	3 hr
May 27, 3:35 AM EDT	Special Weather Statement	PHI	Berks	55 min
May 27, 3:46 AM EDT	Special Weather Statement	PHI	Bucks, Montgomery	59 min
May 27, 4:08 AM EDT	Flash Flood Warning	PHI	Bucks, Montgomery	4 hr
May 27, 4:35 AM EDT	Special Weather Statement	PHI	Berks	55 min
May 27, 4:46 AM EDT	Special Weather Statement	PHI	Philadelphia	59 min
May 27, 4:58 AM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery, Philadelphia	83 min
May 27, 5:08 AM EDT	Areal Flood Advisory	PHI	Berks	89 min
May 27, 5:18 AM EDT	Special Weather Statement	PHI	Berks	57 min
May 27, 5:47 AM EDT	Special Weather Statement	PHI	Berks	58 min
May 27, 5:57 AM EDT	Flash Flood Warning	PHI	Bucks, Montgomery, Philadelphia	2 hr
May 27, 8:48 AM EDT	Special Weather Statement	PHI	Montgomery	42 min
May 27, 9:26 AM EDT	Special Weather Statement	PHI	Bucks, Lehigh	49 min
May 27, 3:01 PM EDT	Excessive Heat Warning	PHI	Delaware, Philadelphia	52 hr
May 27, 4:56 PM EDT	Special Weather Statement	PHI	Berks	49 min
May 27, 5:51 PM EDT	Areal Flood Warning	PHI	Montgomery	95 min
May 27, 7:36 PM EDT	Special Weather Statement	PHI	Monroe	39 min
May 27, 7:45 PM EDT	Special Weather Statement	PHI	Berks	45 min

Nearby

Areal Flood Warnings in Pennsylvania, 2012 Every areal 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.