Alert archive / Pennsylvania / Flash Flood Warnings in 2021

Flash Flood Warning 74, NWS Philadelphia/Mount Holly

September 1, 2021Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 1, 2021, 7:05 PM EDT for Bucks County, Pennsylvania. It was in force for 8 hr. 19 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 1, 2021, 7:05 PM EDT (23:05 UTC)
Expired
Sep 2, 2021, 3:00 AM EDT
In force
8 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Emergency
Flash flood emergency
Damage threat
Catastrophic
Flood severity
None

County Bucks County, PA

The radar

The Philadelphia radar (KDIX), 62 km from the middle of the area, began a volume at 23:04 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 1, 7:10 PM EDTFLASH FLOOD2 Ssw Richboro, PAFLOODING CLOSED BRSTOL ROAD, OLD BRISTOL ROAD, CHINQUAPIN ROAD, AND GIBSON ROAD. TIME BASED ON DISPATCH REPORT.
Sep 1, 7:15 PM EDTFLASH FLOOD1 Sw Wrightstown Twp, PATHE GAUGE ON NESHAMINY CREEK AT PENNS PARK (PEPP1) REACHED FLOOD STAGE AT 715 PM 9/1.
Sep 1, 7:30 PM EDTFLASH FLOOD1 E Souderton, PAFLOODING CLOSED BETHLEHEM PIKE NORTH OF STATE HIGHWAY 309. TIME BASED ON DISPATCH REPORT.
Sep 1, 7:42 PM EDTFLASH FLOOD1 Nw Bensalem, PAFLOODING CLOSED GALLOWAY ROAD NEAR I-276. TIME BASED ON DISPATCH REPORT.
Sep 1, 7:54 PM EDTFLASH FLOODSellersville, PADIAMOND STREET AND MAIN STREET CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT.
Sep 1, 7:55 PM EDTFLASH FLOOD1 Se Perkasie, PASTATE HIGHWAY 152 BETWEEN SELLERSVILLE AND PERKASIE CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT.
Sep 1, 7:57 PM EDTFLASH FLOOD2 E East Rockhill Twp, PASTATE HIGHWAY 313 CLOSED FROM FLOODING NEAR EAST BRANCH PERKIOMEN CREEK. TIME BASED ON DISPATCH REPORT.
Sep 1, 8:00 PM EDTFLASH FLOOD1 Nnw Silverdale, PACALLOWHILL ROAD AT SOUTH PERKASIE ROAD IS STARTING TO WASH AWAY.
Sep 1, 8:30 PM EDTFLASH FLOOD2 Sse Village Shires, PATHE GAUGE ON NESHAMINY CREEK NEAR LANGHORNE (LNGP1) REACHED FLOOD STAGE AT 830 PM 9/1, CRESTING AT 20.84 FEET (MAJOR FLOODING) AT 630 AM 9/2.
Sep 1, 9:11 PM EDTFLASH FLOOD2 Ene Hilltown Twp, PAHILLTOWN PIKE WASHED OUT FROM FLOODING. TIME BASED ON DISPATCH REPORT.
Sep 1, 9:27 PM EDTFLASH FLOODChalfont, PAFLASH FLOODING OF NESHAMINY CREEK FORCED THE CLOSURE OF BUTLER AVENUE. TIME BASED ON DISPATCH REPORT.
Sep 1, 10:00 PM EDTFLASH FLOODMilford Twp, PA*** 1 FATAL *** ONE FATALITY FROM FLASH FLOODING IN MILFORD AFTER A VEHICLE BECAME STUCK IN FLOOD WATERS.
Sep 1, 11:31 PM EDTFLASH FLOOD2 Ese East Rockhill Twp, PABLUE SCHOOL ROAD CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT.
Sep 1, 11:32 PM EDTFLASH FLOOD2 Ne Warminster, PAMEARNS ROAD WASHED OUT FROM FLOODING. TIME BASED ON DISPATCH REPORT.
Sep 1, 11:41 PM EDTFLASH FLOOD1 Nne Richboro, PAWORTHINGTON MILL ROAD CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT.
Sep 2, 12:45 AM EDTFLASH FLOOD2 Ssw Wrightstown Twp, PASTATE HIGHWAY 232 CLOSED OVER NESHAMINY CREEK FROM FLASH FLOODING. TIME BASED ON DISPATCH REPORT.
Sep 2, 1:00 AM EDTHEAVY RAIN 6.8East Rockhill Twp, PA
Sep 2, 1:37 AM EDTFLASH FLOOD1 N Village Shires, PAFLASH FLOODING OF NESHAMINY CREEK FORCED THE CLOSURE OF STATE HIGHWAY 332. TIME BASED ON DISPATCH REPORT.
Sep 2, 1:40 AM EDTFLASH FLOOD1 Ese Eddington, PARADCLIFFE STREET AND STATE ROAD CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT.

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 12:00Z, 11.1 hours before the alert went out and 196 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 12:00Z on 2021-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 51 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 12:00Z on 2021-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 31 square meters per square second.19395878Sfc1 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
51 J/kg
Mixed-layer CIN
-80 J/kg
Mixed-layer LCL
1274 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
31 m²/s²
0-3 km storm-relative helicity
201 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

971 
WGUS51 KPHI 012305
FFWPHI
PAC017-020400-
/O.NEW.KPHI.FF.W.0074.210901T2305Z-210902T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
705 PM EDT Wed Sep 1 2021

...FLASH FLOOD EMERGENCY FOR A LARGE PORTION OF BUCKS COUNTY...

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Bucks County in southeastern Pennsylvania...

* Until midnight EDT.

* At 705 PM EDT, emergency management reported thunderstorms 
  producing heavy rain across the warned area. Between 3 and 7 
  inches of rain have fallen. Widespread flash flooding is occurring.

  This is a FLASH FLOOD EMERGENCY for a large portion of Bucks 
  County. This is a PARTICULARLY DANGEROUS SITUATION. SEEK HIGHER 
  GROUND NOW!

  HAZARD...Life threatening flash flooding caused by
           thunderstorms.

  SOURCE...Emergency management reported.

  IMPACT...This is a PARTICULARLY DANGEROUS SITUATION. SEEK
           HIGHER GROUND NOW! Life threatening flash flooding of
           low water crossings, small creeks and streams, urban
           areas, highways, streets, and underpasses.

* Some locations that may experience flash flooding include...
  Bensalem, Quakertown, Perkasie, Doylestown, Bedminster, Chalfont, 
  Tinicum, Newtown, Dublin, Langhorne, and Ivyland.

This includes the following highways...
	Pennsylvania Turnpike between mile markers 347 and 355.
	Interstate 95 in Pennsylvania between mile markers 36 and 37.
	Northeast Extension between mile markers 39 and 44.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to higher ground now! This is an extremely dangerous and 
life-threatening situation. Do not attempt to travel unless you are 
fleeing an area subject to flooding or under an evacuation order.

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

&&

LAT...LON 4024 7485 4007 7493 4009 7496 4012 7496
      4014 7502 4042 7548 4058 7525

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CATASTROPHIC

$$

CMS
3 follow-up statements
419 
WGUS71 KPHI 012343
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
743 PM EDT Wed Sep 1 2021

PAC017-020400-
/O.CON.KPHI.FF.W.0074.000000T0000Z-210902T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-
743 PM EDT Wed Sep 1 2021

...FLASH FLOOD EMERGENCY FOR A LARGE PORTION OF BUCKS COUNTY...

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL MIDNIGHT EDT TONIGHT 
FOR BUCKS COUNTY...

At 743 PM EDT, emergency management reported flash flooding across 
the warned area. Numerous water rescues are being conducted across 
the county. Avoid traveling in this area tonight! Between 3 and 7 
inches of rain have fallen. Flash flooding is already occurring.

This is a FLASH FLOOD EMERGENCY for a large portion of Bucks County. 
This is a PARTICULARLY DANGEROUS SITUATION. SEEK HIGHER GROUND NOW!

HAZARD...Life threatening flash flooding caused by heavy rain.

SOURCE...Emergency management reported.

IMPACT...This is a PARTICULARLY DANGEROUS SITUATION. SEEK HIGHER
         GROUND NOW! Life threatening flash flooding of low water
         crossings, small creeks and streams, urban areas,
         highways, streets, and underpasses.

Some locations that may experience flash flooding include...
  Bensalem, Quakertown, Perkasie, Doylestown, Bedminster, Chalfont, 
  Tinicum, Newtown, Dublin, Langhorne, and Ivyland.

This includes the following highways...
	Pennsylvania Turnpike between mile markers 347 and 355.
	Interstate 95 in Pennsylvania between mile markers 36 and 37.
	Northeast Extension between mile markers 40 and 44.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to higher ground now! This is an extremely dangerous and 
life-threatening situation. Do not attempt to travel unless you are 
fleeing an area subject to flooding or under an evacuation order.

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

&&

LAT...LON 4024 7485 4007 7493 4009 7496 4012 7496
      4014 7502 4042 7548 4058 7525

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CATASTROPHIC

$$

CMS
358 
WGUS51 KPHI 020332
FFWPHI
PAC017-020700-
/O.EXT.KPHI.FF.W.0074.000000T0000Z-210902T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1132 PM EDT Wed Sep 1 2021

The National Weather Service in Mount Holly has extended the

* Flash Flood Warning for...
  Bucks County in southeastern Pennsylvania...

* Until 300 AM EDT.

* At 1132 PM EDT, emergency management reported flash flooding 
  across the warned area. Numerous roads remain closed with some 
  reported washed out. Several river and stream gauges remain in 
  flood. Avoid travel in the warned area. Between 4 and 8 inches of 
  rain have fallen. Flash flooding is already occurring.

  HAZARD...Life threatening flash flooding caused by heavy rain.

  SOURCE...Emergency management reported.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets, and underpasses.

* Some locations that may experience flash flooding include...
  Philadelphia, Bensalem, Quakertown, Perkasie, Doylestown, 
  Bedminster, Chalfont, Tinicum, Newtown, Dublin, Langhorne, and 
  Ivyland.

This includes the following highways...
	Pennsylvania Turnpike between mile markers 347 and 355.
	Interstate 95 in Pennsylvania between mile markers 36 and 37.
	Northeast Extension between mile markers 40 and 44.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4024 7485 4007 7493 4009 7496 4012 7496
      4014 7502 4042 7548 4058 7525

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

CMS
888 
WGUS71 KPHI 020653
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
253 AM EDT Thu Sep 2 2021

PAC017-020703-
/O.EXP.KPHI.FF.W.0074.000000T0000Z-210902T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-
253 AM EDT Thu Sep 2 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 3 AM EDT EARLY THIS MORNING 
FOR BUCKS COUNTY...

The flash flood warning has been replaced by a flood warning. Please 
continue to heed road closures.

LAT...LON 4024 7485 4007 7493 4009 7496 4012 7496
      4014 7502 4042 7548 4058 7525

$$

CMS

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 1, 6:19 AM EDTAreal Flood AdvisoryPHIChester, Delaware116 min
Sep 1, 6:49 AM EDTFlash Flood WarningPHIChester, Delaware, Philadelphia86 min
Sep 1, 11:24 AM EDTAreal Flood AdvisoryPHIBerks, Carbon, Lehigh, Monroe, Northampton3 hr
Sep 1, 12:07 PM EDTFlash Flood WarningPHICarbon, Monroe4 hr
Sep 1, 1:29 PM EDTFlash Flood WarningPHIBerks, Lehigh6 hr
Sep 1, 2:53 PM EDTFlash Flood WarningPHIBerks, Chester, Delaware, Montgomery9 hr
Sep 1, 3:55 PM EDTRiver Flood WarningPHIMontgomery36 hr
Sep 1, 3:55 PM EDTRiver Flood WarningPHIChester, Montgomery, Philadelphia43 hr
Sep 1, 3:55 PM EDTRiver Flood WarningPHIMontgomery, Philadelphia41 hr
Sep 1, 3:55 PM EDTRiver Flood WarningPHIPhiladelphia39 hr
Sep 1, 3:55 PM EDTRiver Flood WarningPHIBerks24 hr
Sep 1, 4:02 PM EDTRiver Flood WarningPHIMonroe24 hr
Sep 1, 4:04 PM EDTAreal Flood WarningPHICarbon, Monroe, Northampton24 hr
Sep 1, 4:10 PM EDTRiver Flood WarningPHIMonroe19 hr
Sep 1, 4:12 PM EDTFlash Flood WarningPHIBerks, Bucks, Lehigh, Montgomery, Northampton7 hr
Sep 1, 4:12 PM EDTRiver Flood WarningPHILehigh, Northampton25 hr
Sep 1, 4:12 PM EDTRiver Flood WarningPHILehigh, Northampton24 hr
Sep 1, 4:12 PM EDTRiver Flood WarningPHICarbon15 hr
Sep 1, 4:13 PM EDTTornado WarningPHIChester32 min
Sep 1, 4:20 PM EDTRiver Flood WarningPHIMontgomery22 hr
Sep 1, 4:21 PM EDTRiver Flood WarningPHIBucks29 hr
Sep 1, 4:42 PM EDTFlash Flood Warning EmergencyConsiderable damage threatPHIChester, Delaware, Montgomery6 hr
Sep 1, 5:07 PM EDTRiver Flood WarningPHIChester17 hr
Sep 1, 5:13 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia47 min
Sep 1, 5:15 PM EDTTornado WarningPHIDelaware, Montgomery, Philadelphia30 min
Sep 1, 5:26 PM EDTFlash Flood WarningPHIBucks, Delaware, Montgomery, Philadelphia9 hr
Sep 1, 5:34 PM EDTTornado WarningPHIBucks, Montgomery, Philadelphia26 min
Sep 1, 5:42 PM EDTFlash Flood WarningPHIBucks10 hr
Sep 1, 5:57 PM EDTTornado WarningPHIBucks33 min
Sep 1, 6:08 PM EDTFlash Flood WarningPHIMonroe, Northampton6 hr
Sep 1, 6:20 PM EDTTornado WarningPHIBucks40 min
Sep 1, 6:22 PM EDTTornado Warning Tornado observedPHIPhiladelphia23 min
Sep 1, 6:38 PM EDTRiver Flood WarningPHIChester, Delaware26 hr
Sep 1, 6:42 PM EDTTornado WarningPHIBucks, Philadelphia33 min
Sep 1, 6:59 PM EDTSevere Thunderstorm WarningPHIBucks61 min
Sep 1, 7:04 PM EDTTornado Warning EmergencyTornado observedCatastrophic damage threatPHIBucks26 min
Sep 1, 7:22 PM EDTTornado WarningPHIBucks11 min
Sep 1, 7:23 PM EDTAreal Flood WarningPHIBerks, Lehigh14 hr
Sep 1, 7:31 PM EDTFlash Flood Warning EmergencyCatastrophic damage threatPHIBucks4 hr
Sep 1, 7:53 PM EDTRiver Flood WarningPHIDelaware13 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2021Every flash 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.