Alert archive / Pennsylvania / Flash Flood Warnings in 2023

Flash Flood Warning 71, NWS Philadelphia/Mount Holly

July 25, 2023Bucks County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 25, 2023, 1:20 PM EDT for Bucks County, Montgomery County, Pennsylvania. It was in force for 5 hr. 3 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 25, 2023, 1:20 PM EDT (17:20 UTC)
Expired
Jul 25, 2023, 6:00 PM EDT
In force
5 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Bucks County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 100 km from the middle of the area, began a volume at 17:23 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 25, 3:00 PM EDTFLASH FLOOD1 Nnw Green Lane, PASeveral photos of several roads completely impassible with a creek overflowing its banks near McLean Station Rd in Red Hill. Time estimated.
Jul 25, 4:13 PM EDTFLOOD2 Sw Trumbauersville, PAPhoto of Trumbauersville Rd flooded near I-476 in Trumbauersville.
Jul 25, 4:53 PM EDTFLOOD2 Ssw Trumbauersville, PAPhoto of Wright Road near Trumbauersville shows water over-running the roadway.

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, 5.3 hours before the alert went out and 224 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 2023-07-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 231 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 2023-07-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 43 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
231 J/kg
Mixed-layer CIN
-60 J/kg
Mixed-layer LCL
960 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
43 m²/s²
0-3 km storm-relative helicity
63 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted.

178 
WGUS51 KPHI 251720
FFWPHI
PAC017-091-252000-
/O.NEW.KPHI.FF.W.0071.230725T1720Z-230725T2000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
120 PM EDT Tue Jul 25 2023

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  West Central Bucks County in southeastern Pennsylvania...
  North Central Montgomery County in southeastern Pennsylvania...

* Until 400 PM EDT.

* At 120 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3 inches of rain 
  have fallen. Additional rainfall amounts of 1 to 2 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets, and underpasses as well as other
           drainage and low lying areas.

* Some locations that may experience flash flooding include...
  Quakertown, Perkasie, Green Lane, Pennsburg, Red Hill, and 
  Trumbauersville.

This includes the following highways...
	Northeast Extension between mile markers 38 and 43.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4037 7553 4041 7547 4046 7538 4039 7528
      4031 7547

FLASH FLOOD...RADAR INDICATED

$$

RCM
2 follow-up statements
461 
WGUS51 KPHI 251938
FFWPHI
PAC017-091-252200-
/O.EXT.KPHI.FF.W.0071.000000T0000Z-230725T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
338 PM EDT Tue Jul 25 2023

The National Weather Service in Mount Holly has extended the

* Flash Flood Warning for...
  West Central Bucks County in southeastern Pennsylvania...
  North Central Montgomery County in southeastern Pennsylvania...

* Until 600 PM EDT.

* At 338 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 3 inches of rain 
  have fallen. Additional rainfall amounts of 1 to 2 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets, and underpasses as well as other
           drainage and low lying areas.

* Some locations that may experience flash flooding include...
  Quakertown, Perkasie, Green Lane, Pennsburg, Red Hill, and 
  Trumbauersville.

This includes the following highways...
	Northeast Extension between mile markers 38 and 43.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4037 7553 4041 7547 4046 7538 4039 7528
      4031 7547

FLASH FLOOD...RADAR INDICATED

$$

RCM
483 
WGUS71 KPHI 252154
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
554 PM EDT Tue Jul 25 2023

PAC017-091-252204-
/O.EXP.KPHI.FF.W.0071.000000T0000Z-230725T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-Montgomery PA-
554 PM EDT Tue Jul 25 2023

...FLASH FLOOD WARNING WILL EXPIRE AT 6 PM EDT THIS EVENING FOR WEST 
CENTRAL BUCKS AND NORTH CENTRAL MONTGOMERY COUNTIES...

The heavy rain has ended and flood waters have receded.Flooding is 
no longer expected to pose a threat.

LAT...LON 4037 7553 4041 7547 4046 7538 4039 7528
      4031 7547

$$

Robertson

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 25, 11:58 AM EDTSpecial Weather StatementPHIMontgomery32 min
Jul 25, 12:07 PM EDTSpecial Weather StatementPHIBerks23 min
Jul 25, 12:16 PM EDTSevere Thunderstorm WarningPHIBucks, Lehigh, Montgomery44 min
Jul 25, 12:31 PM EDTSpecial Weather StatementPHIBerks29 min
Jul 25, 12:33 PM EDTSpecial Weather StatementPHIBerks27 min
Jul 25, 12:37 PM EDTSpecial Weather StatementPHICarbon38 min
Jul 25, 12:47 PM EDTAreal Flood AdvisoryPHIBucks, Montgomery33 min
Jul 25, 12:56 PM EDTSpecial Weather StatementPHINorthampton34 min
Jul 25, 1:00 PM EDTSpecial Weather StatementPHIBerks30 min
Jul 25, 1:03 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery42 min
Jul 25, 1:06 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe, Northampton39 min
Jul 25, 1:10 PM EDTSpecial Weather StatementPHIDelaware35 min
Jul 25, 1:12 PM EDTSpecial Weather StatementPHIMonroe33 min
Jul 25, 1:27 PM EDTAreal Flood AdvisoryPHIBerks3 hr
Jul 25, 1:27 PM EDTSevere Thunderstorm WarningPHIBucks48 min
Jul 25, 1:37 PM EDTAreal Flood AdvisoryPHICarbon3 hr
Jul 25, 1:38 PM EDTFlash Flood WarningPHIDelaware4 hr
Jul 25, 1:41 PM EDTAreal Flood AdvisoryPHILehigh, Northampton3 hr
Jul 25, 1:42 PM EDTSpecial Weather StatementPHIPhiladelphia33 min
Jul 25, 1:49 PM EDTSpecial Weather StatementPHIChester26 min
Jul 25, 1:54 PM EDTFlash Flood WarningPHIDelaware, Philadelphia4 hr
Jul 25, 1:55 PM EDTAreal Flood AdvisoryPHIMonroe2 hr
Jul 25, 2:06 PM EDTSevere Thunderstorm WarningPHIMonroe39 min
Jul 25, 2:14 PM EDTSevere Thunderstorm WarningPHIChester, Montgomery46 min
Jul 25, 2:21 PM EDTAreal Flood AdvisoryPHIBerks, Chester, Montgomery2 hr
Jul 25, 2:36 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Montgomery, Philadelphia39 min
Jul 25, 2:51 PM EDTFlash Flood WarningPHIChester, Montgomery3 hr
Jul 25, 2:57 PM EDTAreal Flood AdvisoryPHIChester3 hr
Jul 25, 3:06 PM EDTAreal Flood AdvisoryPHIBucks, Chester, Montgomery95 min
Jul 25, 3:13 PM EDTFlash Flood WarningPHIChester4 hr
Jul 25, 3:16 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia44 min
Jul 25, 3:21 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia39 min
Jul 25, 3:34 PM EDTFlash Flood WarningPHIChester, Montgomery3 hr
Jul 25, 3:58 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia30 min
Jul 25, 4:04 PM EDTAreal Flood AdvisoryPHIBucks, Chester, Delaware, Montgomery, Philadelphia3 hr
Jul 25, 4:55 PM EDTFlash Flood WarningPHIChester118 min
Jul 25, 5:07 PM EDTRiver Flood WarningPHIChester6 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2023Every flash flood warning in 2023

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.