Alert archive / Pennsylvania / Areal Flood Warnings in 2021

Areal Flood Warning 9, NWS Philadelphia/Mount Holly

July 12, 2021Bucks County, Philadelphia County, Pennsylvania; Burlington County, New Jersey

NWS Philadelphia/Mount Holly issued this areal flood warning at Jul 12, 2021, 8:37 PM EDT for Bucks County, Philadelphia County, Pennsylvania; Burlington County, New Jersey. It was in force for 9 hr. 9 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
Jul 12, 2021, 8:37 PM EDT (00:37 UTC)
Expired
Jul 13, 2021, 5:39 AM EDT
In force
9 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Burlington County, NJ, Bucks County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 45 km from the middle of the area, began a volume at 00:39 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.

What was reported inside it

TimeReportWhereRemark
Jul 12, 8:41 PM EDTHEAVY RAIN 5.041 Nnw Andalusia, PAPERSONAL WEATHER STATION KPAPHILA284, AN AMBIENT WEATHER SENSOR.
Jul 12, 8:44 PM EDTHEAVY RAIN 3.99Northeast Philadelphia, PAKPNE ASOS MEASUREMENT.
Jul 12, 8:45 PM EDTHEAVY RAIN 2.731 Wsw Cinnaminson, NJCWOP STATION AR824 CINNAMINSON.
Jul 12, 8:47 PM EDTHEAVY RAIN 4.332 S Fieldsboro, NJCWOP STATION CW2398 BORDENTOWN.
Jul 12, 8:50 PM EDTHEAVY RAIN 3.661 Sse Northeast Philade, PAMESONET STATION 9068D 1 SE NORTHEAST PHILADELPHIA.
Jul 12, 8:54 PM EDTHEAVY RAIN 2.62Delran, NJMESONET STATION BLRNG DELRAN.
Jul 12, 8:55 PM EDTHEAVY RAIN 2.271 Wnw Palmyra, NJMESONET STATION PLMCP PALMYRA.
Jul 12, 9:54 PM EDTHEAVY RAIN 7.63Florence, NJ
Jul 12, 10:02 PM EDTHEAVY RAIN 2.65Bordentown, NJ

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 0.6 hours before the alert went out and 193 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, Brookhaven, NY at 00:00Z on 2021-07-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 196 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, Brookhaven, NY at 00:00Z on 2021-07-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 29 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
196 J/kg
Mixed-layer CIN
-75 J/kg
Mixed-layer LCL
501 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
63 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.2

Open this sounding in Storm Lab

The text

As transmitted.

500 
WGUS41 KPHI 130037
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
837 PM EDT Mon Jul 12 2021

NJC005-PAC017-101-131200-
/O.NEW.KPHI.FA.W.0009.210713T0037Z-210713T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Burlington NJ-Bucks PA-Philadelphia PA-
837 PM EDT Mon Jul 12 2021

The National Weather Service in Mount Holly has issued a

* Flood Warning for...
  Northwestern Burlington County in southern New Jersey...
  Southeastern Bucks County in southeastern Pennsylvania...
  Northeastern Philadelphia County in southeastern Pennsylvania...

* Until 800 AM EDT Tuesday.

* At 837 PM EDT, Doppler radar, rain gauges and weather spotters 
  indicated that from 6 to around 10 inches of rain fell in the 
  warned area today. While no additional heavy rain is expected, 
  residual flooding will continue overnight.

* Some locations that are experiencing flooding include...
  Philadelphia, Bensalem, Willingboro, Florence, Burlington, 
  Bristol, Riverside, Palmyra, Bordentown, Beverly, and Tullytown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Motorists should not attempt to drive around barricades or drive 
cars through flooded areas.

&&

LAT...LON 3999 7507 4004 7514 4006 7510 4007 7509
      4014 7502 4022 7478 4017 7473 4015 7472
      4016 7471 4018 7471 4018 7470 4014 7462
      3996 7502 3998 7501 4000 7503

$$

Iovino
3 follow-up statements
897 
WGUS81 KPHI 130528
FLSPHI

Flood Statement
National Weather Service Mount Holly NJ
128 AM EDT Tue Jul 13 2021

NJC005-PAC017-101-131200-
/O.CON.KPHI.FA.W.0009.000000T0000Z-210713T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Burlington NJ-Bucks PA-Philadelphia PA-
128 AM EDT Tue Jul 13 2021

...FLOOD WARNING REMAINS IN EFFECT UNTIL 8 AM EDT THIS MORNING FOR 
NORTHWESTERN BURLINGTON, SOUTHEASTERN BUCKS, AND NORTHEASTERN 
PHILADELPHIA COUNTIES...

At 128 AM EDT, Doppler radar, rain gauges, and weather spotters 
reported that between 6 and 10 inches of rain fell across the warned 
area Monday afternoon and Monday night. Residual flooding will 
continue through the overnight hours. While additional widespread 
heavy rain should west of the warned area, additional pockets of 
locally moderate rain may exacerbate flooding already occurring.

Some locations that will experience flooding include...
  Philadelphia, Trenton, Bensalem, Willingboro, Florence, 
  Burlington, Bristol, Riverside, Palmyra, Bordentown, Beverly, and 
  Tullytown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around...don't drown when encountering flooded roads. Most 
flood deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Be aware of your surroundings and do not drive on flooded roads.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3999 7507 4004 7514 4006 7510 4007 7509
      4014 7502 4022 7478 4017 7473 4015 7472
      4016 7471 4018 7471 4018 7470 4014 7462
      3996 7502 3998 7501 4000 7503

$$

MPS
714 
WGUS81 KPHI 130710
FLSPHI

Flood Statement
National Weather Service Mount Holly NJ
310 AM EDT Tue Jul 13 2021

NJC005-130720-
/O.CAN.KPHI.FA.W.0009.000000T0000Z-210713T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Burlington NJ-
310 AM EDT Tue Jul 13 2021

...FLOOD WARNING IS CANCELLED FOR NORTHWESTERN BURLINGTON COUNTY...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

A Flash Flood Watch remains in effect until 500 AM EDT for portions 
of New Jersey...and Pennsylvania.

LAT...LON 3999 7507 4004 7514 4006 7510 4006 7509
      4007 7509 4014 7502 4022 7478 4015 7472
      4014 7474 4012 7478 4013 7482 4010 7484
      4008 7486 4006 7494 4002 7501 4001 7505
      3999 7506

$$

PAC017-101-131200-
/O.CON.KPHI.FA.W.0009.000000T0000Z-210713T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-Philadelphia PA-
310 AM EDT Tue Jul 13 2021

...FLOOD WARNING REMAINS IN EFFECT UNTIL 8 AM EDT THIS MORNING FOR 
SOUTHEASTERN BUCKS AND NORTHEASTERN PHILADELPHIA COUNTIES...

At 310 AM EDT, Doppler radar, rain gauges, and weather spotters 
reported that between 6 and 10 inches of rain fell across the warned 
area Monday afternoon and Monday night. Residual flooding will 
continue through the morning hours. Roads may still be closed and 
even washed out in the hardest hit areas.

Some locations that will experience flooding include...
  Philadelphia, Trenton, Bensalem, Burlington, Bristol, Palmyra, 
  Beverly, Tullytown, Langhorne, Andalusia, Feasterville-Trevose, 
  and Levittown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around...don't drown when encountering flooded roads. Most 
flood deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3999 7507 4004 7514 4006 7510 4006 7509
      4007 7509 4014 7502 4022 7478 4015 7472
      4014 7474 4012 7478 4013 7482 4010 7484
      4008 7486 4006 7494 4002 7501 4001 7505
      3999 7506

$$

MPS
745 
WGUS81 KPHI 130939
FLSPHI

Flood Statement
National Weather Service Mount Holly NJ
539 AM EDT Tue Jul 13 2021

PAC017-101-130949-
/O.CAN.KPHI.FA.W.0009.000000T0000Z-210713T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-Philadelphia PA-
539 AM EDT Tue Jul 13 2021

...FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN BUCKS AND 
NORTHEASTERN PHILADELPHIA COUNTIES...

Flood waters have receded. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3999 7507 4004 7514 4006 7510 4006 7509
      4007 7509 4014 7502 4022 7478 4015 7472
      4014 7474 4012 7478 4013 7482 4010 7484
      4008 7486 4006 7494 4002 7501 4001 7505
      3999 7506

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 13, 1:34 AM EDTAreal Flood AdvisoryPHIBerks, Chester, Montgomery117 min
Jul 13, 3:44 PM EDTDense Fog AdvisoryPHIBucks, Monroe, Northampton14 hr
Jul 12, 9:53 PM EDTAreal Flood AdvisoryPHISussex, Warren3 hr
Jul 12, 10:34 PM EDTAreal Flood AdvisoryPHIMorris3 hr
Jul 13, 8:09 AM EDTMarine Dense Fog AdvisoryPHI25 hr

Nearby

Areal Flood Warnings in Pennsylvania, 2021Areal Flood Warnings in New Jersey, 2021Every areal flood warning in 2021

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.