Alert archive / Pennsylvania / Flash Flood Warnings in 2024

Flash Flood Warning 19, NWS Philadelphia/Mount Holly

July 14, 2024Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 14, 2024, 2:53 PM EDT for Chester County, 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: Jul 14, 2024, 2:53 PM EDT (18:53 UTC)
Expired: Jul 14, 2024, 5:32 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Chester County, PA

The radar

The Philadelphia radar (KDIX), 112 km from the middle of the area, began a volume at 18:52 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.9 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-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: 940 J/kg
Mixed-layer CIN: -112 J/kg
Mixed-layer LCL: 1366 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 26 m²/s²
0-3 km storm-relative helicity: 53 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

830 
WGUS51 KPHI 141853
FFWPHI
PAC029-142300-
/O.NEW.KPHI.FF.W.0019.240714T1853Z-240714T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
253 PM EDT Sun Jul 14 2024

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  North Central Chester County in southeastern Pennsylvania...

* Until 700 PM EDT.

* At 253 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 inches of 
  rain have fallen. The expected rainfall rate is 1.5 to 2.5 inches 
  in 1 hour. Additional rainfall amounts of 1 to 1.5 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...
  Elverson, Glenmoore, Pughtown, Lionville, Lionville-Marchwood, 
  Chester Springs and Exton.

This includes Pennsylvania Turnpike between mile markers 301 and 317.

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 4003 7574 4012 7589 4020 7575 4015 7556
      4004 7558

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1.5-2.5 INCHES IN 1 HOUR

$$

Gorse

2 follow-up statements

962 
WGUS71 KPHI 141936
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
336 PM EDT Sun Jul 14 2024

PAC029-142300-
/O.CON.KPHI.FF.W.0019.000000T0000Z-240714T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-
336 PM EDT Sun Jul 14 2024

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 PM EDT THIS EVENING 
FOR NORTH CENTRAL CHESTER COUNTY...

At 336 PM EDT, Doppler radar indicated the strongest thunderstorms 
producing heavy rain have shifted south and east of the warned area, 
however some additional showers continue. Between 1.5 and 3 inches 
of rain have fallen. 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...
  Elverson, Glenmoore, Pughtown, Lionville, Lionville-Marchwood, 
  Chester Springs and Exton.

This includes Pennsylvania Turnpike between mile markers 301 and 317.

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 4003 7574 4012 7589 4020 7575 4015 7556
      4004 7558

FLASH FLOOD...RADAR INDICATED

$$

Gorse

964 
WGUS71 KPHI 142132
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
532 PM EDT Sun Jul 14 2024

PAC029-142142-
/O.CAN.KPHI.FF.W.0019.000000T0000Z-240714T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-
532 PM EDT Sun Jul 14 2024

...FLASH FLOOD WARNING IS CANCELLED FOR NORTH CENTRAL CHESTER 
COUNTY...

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

&&

LAT...LON 4003 7574 4012 7589 4020 7575 4015 7556
      4004 7558

$$

Gorse

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 14, 12:07 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	38 min
Jul 14, 12:44 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh, Montgomery	46 min
Jul 14, 1:23 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery	52 min
Jul 14, 2:19 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Montgomery	41 min
Jul 14, 2:24 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	23 min
Jul 14, 2:52 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery	38 min
Jul 14, 3:03 PM EDT	Excessive Heat Warning	PHI	Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 2 more	3 days
Jul 14, 3:03 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	42 min
Jul 14, 3:35 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	40 min
Jul 14, 3:44 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	46 min
Jul 14, 4:13 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	47 min
Jul 14, 4:22 PM EDT	Severe Thunderstorm Warning Considerable damage threat	PHI	Bucks	32 min

Nearby

Flash Flood Warnings in Pennsylvania, 2024 Every flash flood warning in 2024

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.