Alert archive / Pennsylvania / Flash Flood Warnings in 2026

Flash Flood Warning 9, NWS Philadelphia/Mount Holly

June 22, 2026Delaware County, Montgomery County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 22, 2026, 6:02 PM EDT for Delaware County, Montgomery County, Philadelphia County, Pennsylvania. It was in force for 4 hr. 4 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
Jun 22, 2026, 6:02 PM EDT (22:02 UTC)
Expired
Jun 22, 2026, 10:00 PM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 79 km from the middle of the area, began a volume at 22:04 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
Jun 22, 6:05 PM EDTFLOOD1 Wsw Shawmont - Philad, PAFlooding on Schuylkill Expressway/I-76 west of Gladwyne. Seen on DOT traffic cameras.
Jun 22, 6:23 PM EDTFLASH FLOOD1 S Wyncote, PAReport of a water rescue.
Jun 22, 6:30 PM EDTFLASH FLOOD2 Ese Mount Airy, PASeveral public reports via social media and relayed via broadcast media showing flooded streets and fast flowing water at least 6 to 12 inches deep in the Germantown area of Philadelphia. Several cars floating in water. Reports of basements flooded along Godfr
Jun 22, 7:09 PM EDTFLASH FLOOD2 Wnw Olney - Philadelp, PANorth Beechwood Street flooded with water almost halfway up the side of multiple cars. Time from report.

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

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.0 hours before the alert went out and 217 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, Washington/Dulle, VA at 12:00Z on 2026-06-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Washington/Dulle, VA at 12:00Z on 2026-06-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 172 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1417 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
172 m²/s²
0-3 km storm-relative helicity
286 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

350 
WGUS51 KPHI 222202
FFWPHI
PAC045-091-101-230100-
/O.NEW.KPHI.FF.W.0009.260622T2202Z-260623T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
602 PM EDT Mon Jun 22 2026

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northeastern Delaware County in southeastern Pennsylvania...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Northwestern Philadelphia County in southeastern Pennsylvania...

* Until 900 PM EDT.

* At 602 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 1.5 inches of 
  rain have fallen. The expected rainfall rate is 1 to 2 inches in 1 
  hour. Additional rainfall amounts of 0.5 to 1.5 inches are 
  possible in the warned area. Flash flooding is already occurring.

  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...
  Philadelphia, Conshohocken, Jenkintown, Narberth, Chestnut Hill, 
  Germantown, Plymouth Meeting, Bryn Mawr, Trout Lake, Radnor 
  Township, King Of Prussia and West Conshohocken.

This includes the following highways...
	Interstate 476 in Pennsylvania between mile markers 10 and 19.
	Interstate 76 in Pennsylvania between mile markers 328 and 339.
	Pennsylvania Turnpike between mile markers 329 and 330.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4011 7530 4014 7514 4003 7508 3999 7537
      4005 7539 4006 7537 4007 7536 4007 7537
      4007 7538 4006 7539 4007 7540 4008 7540

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR

$$

MJL
3 follow-up statements
059 
WGUS51 KPHI 230034
FFWPHI
PAC045-091-101-230200-
/O.EXT.KPHI.FF.W.0009.000000T0000Z-260623T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
834 PM EDT Mon Jun 22 2026

The National Weather Service in Mount Holly has extended the

* Flash Flood Warning for...
  Northeastern Delaware County in southeastern Pennsylvania...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Northwestern Philadelphia County in southeastern Pennsylvania...

* Until 1000 PM EDT.

* At 834 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Flash flooding is already occurring.

  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...
  Philadelphia, Conshohocken, Jenkintown, Narberth, Chestnut Hill, 
  Germantown, Plymouth Meeting, Bryn Mawr, Trout Lake, Radnor 
  Township, King Of Prussia and West Conshohocken.

This includes the following highways...
	Interstate 476 in Pennsylvania between mile markers 10 and 19.
	Interstate 76 in Pennsylvania between mile markers 328 and 339.
	Pennsylvania Turnpike between mile markers 329 and 330...and
	between mile markers 332 and 334.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4011 7530 4014 7514 4003 7508 3999 7537
      4005 7539 4006 7537 4007 7536 4007 7537
      4007 7538 4006 7539 4007 7540 4008 7540

FLASH FLOOD...RADAR INDICATED

$$

MJL
185 
WGUS71 KPHI 230104
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
904 PM EDT Mon Jun 22 2026

PAC045-091-101-230200-
/O.CON.KPHI.FF.W.0009.000000T0000Z-260623T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Delaware PA-Montgomery PA-Philadelphia PA-
904 PM EDT Mon Jun 22 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 10 PM EDT THIS 
EVENING FOR NORTHEASTERN DELAWARE, SOUTHEASTERN MONTGOMERY AND 
NORTHWESTERN PHILADELPHIA COUNTIES...

At 904 PM EDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain across the warned area. Between 1 
and 2.5 inches of rain have fallen. Flooding impacts will continue, 
but no additional rainfall is expected. Flash flooding is already 
occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar and automated gauges.

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...
  Philadelphia, Conshohocken, Jenkintown, Narberth, Chestnut Hill, 
  Germantown, Plymouth Meeting, Bryn Mawr, Trout Lake, Radnor 
  Township, King Of Prussia and West Conshohocken.

This includes the following highways...
	Interstate 476 in Pennsylvania between mile markers 10 and 19.
	Interstate 76 in Pennsylvania between mile markers 328 and 339.
	Pennsylvania Turnpike between mile markers 329 and 330...and
	between mile markers 332 and 334.

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 4011 7530 4014 7514 4003 7508 3999 7537
      4005 7539 4006 7537 4007 7536 4007 7537
      4007 7538 4006 7539 4007 7540 4008 7540

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

Guzzo
077 
WGUS71 KPHI 230153
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
953 PM EDT Mon Jun 22 2026

PAC045-091-101-230203-
/O.EXP.KPHI.FF.W.0009.000000T0000Z-260623T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Delaware PA-Montgomery PA-Philadelphia PA-
953 PM EDT Mon Jun 22 2026

...FLASH FLOOD WARNING WILL EXPIRE AT 10 PM EDT THIS EVENING FOR 
NORTHEASTERN DELAWARE, SOUTHEASTERN MONTGOMERY AND NORTHWESTERN 
PHILADELPHIA COUNTIES...

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

A Flood Watch remains in effect until 600 AM EDT Tuesday for 
portions of northern Delaware, New Jersey, and southeast 
Pennsylvania.

&&

LAT...LON 4011 7530 4014 7514 4003 7508 3999 7537
      4005 7539 4006 7537 4007 7536 4007 7537
      4007 7538 4006 7539 4007 7540 4008 7540

$$

Guzzo

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 22, 2:13 AM EDTFlood WatchPHIBucks, Chester, Delaware, Montgomery, Philadelphia25 hr
Jun 22, 2:20 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia40 min
Jun 22, 2:55 PM EDTSevere Thunderstorm WarningPHIBucks50 min
Jun 22, 4:15 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Delaware, Montgomery45 min
Jun 22, 4:35 PM EDTTornado WarningPHIBerks, Chester, Delaware, Montgomery25 min
Jun 22, 4:56 PM EDTTornado WarningPHIChester, Delaware, Montgomery34 min
Jun 22, 5:18 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery42 min
Jun 22, 5:22 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia53 min
Jun 22, 5:53 PM EDTSevere Thunderstorm WarningPHIBucks52 min
Jun 22, 6:02 PM EDTSevere Thunderstorm WarningPHIDelaware, Philadelphia43 min
Jun 22, 6:09 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia51 min
Jun 22, 6:26 PM EDTFlash Flood WarningPHIBucks, Montgomery, Philadelphia4 hr
Jun 22, 6:36 PM EDTFlash Flood WarningPHIPhiladelphia3 hr
Jun 22, 6:48 PM EDTFlash Flood WarningPHIBucks3 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2026Every flash flood warning in 2026

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.