Alert archive / Pennsylvania / Flash Flood Warnings in 2024

Flash Flood Warning 4, NWS Philadelphia/Mount Holly

June 14, 2024Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 14, 2024, 5:07 PM EDT for Chester County, Pennsylvania. It was in force for 4 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: Jun 14, 2024, 5:07 PM EDT (21:07 UTC)
Expired: Jun 14, 2024, 9:15 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Chester County, PA

The radar

The Philadelphia radar (KDIX), 110 km from the middle of the area, began a volume at 21:07 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, 9.1 hours before the alert went out and 180 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: 50 J/kg
Mixed-layer CIN: -171 J/kg
Mixed-layer LCL: 1393 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 28 m²/s²
0-3 km storm-relative helicity: 33 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

771 
WGUS51 KPHI 142107
FFWPHI
PAC029-150115-
/O.NEW.KPHI.FF.W.0004.240614T2107Z-240615T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
507 PM EDT Fri Jun 14 2024

The National Weather Service in Mount Holly has issued a

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

* Until 915 PM EDT.

* At 507 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 inches of 
  rain have fallen. Additional rainfall amounts up to 0.5 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...
  Marshallton.

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 3987 7561 3984 7583 3993 7585 3996 7562

FLASH FLOOD...RADAR INDICATED

$$

AKL

1 follow-up statement

009 
WGUS71 KPHI 142232
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
632 PM EDT Fri Jun 14 2024

PAC029-150115-
/O.CON.KPHI.FF.W.0004.000000T0000Z-240615T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-
632 PM EDT Fri Jun 14 2024

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 915 PM EDT THIS 
EVENING FOR SOUTH CENTRAL CHESTER COUNTY...

At 632 PM EDT, Doppler radar indicated earlier thunderstorms that 
produced heavy rain across the warned area. Between 2 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...
  Marshallton.

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 3987 7561 3984 7583 3993 7585 3996 7562

FLASH FLOOD...RADAR INDICATED

$$

AKL

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 14, 4:14 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	46 min
Jun 14, 4:37 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	38 min
Jun 14, 4:40 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Northampton	50 min
Jun 14, 5:17 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Montgomery, Philadelphia	43 min
Jun 14, 5:23 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	52 min
Jun 14, 5:37 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	38 min
Jun 14, 5:59 PM EDT	Flash Flood Warning	PHI	Bucks, Montgomery, Philadelphia	4 hr
Jun 14, 6:09 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	21 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.