Alert archive / Delaware / Flash Flood Warnings in 2023

Flash Flood Warning 46, NWS Philadelphia/Mount Holly

July 9, 2023New Castle County, Delaware; Salem County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 9, 2023, 5:09 PM EDT for New Castle County, Delaware; Salem County, New Jersey. It was in force for 4 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 9, 2023, 5:09 PM EDT (21:09 UTC)
Expired: Jul 9, 2023, 8:45 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties New Castle County, DE, Salem County, NJ

The radar

The Dover AFB radar (KDOX), 97 km from the middle of the area, began a volume at 21:08 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

Time	Report	Where	Remark
Jul 9, 5:15 PM EDT	FLOOD	1 Se Monterey Farms, DE	DELDOT camera shows Hamburg Road just west of DE Route 9 is flooded with water flowing across the roadway. Vehicles unable to pass.
Jul 9, 5:35 PM EDT	FLOOD	Washington Park, DE	Flooding occurring at the intersection of Washington Street & W. Seventh Street in New Castle. Report via social media.
Jul 9, 6:05 PM EDT	FLASH FLOOD	2 Ne Pennsville, NJ	Closed due to flooding inPennsville on Rt 49 EB between I-295/US-40 and Chestnut St.

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, 9.2 hours before the alert went out and 178 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: 952 J/kg
Mixed-layer CIN: -58 J/kg
Mixed-layer LCL: 686 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 12 m²/s²
0-3 km storm-relative helicity: 37 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

700 
WGUS51 KPHI 092109
FFWPHI
DEC003-NJC033-100045-
/O.NEW.KPHI.FF.W.0046.230709T2109Z-230710T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
509 PM EDT Sun Jul 9 2023

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  New Castle County in northern Delaware...
  Western Salem County in southern New Jersey...

* Until 845 PM EDT.

* At 509 PM EDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  1 and 3 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 
  inch are possible in the warned area. Flash flooding is ongoing or 
  expected to begin shortly.

  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...
  Wilmington, Newark, Middletown, Pennsville, Carneys Point, 
  Elsmere, New Castle, Penns Grove, Salem, Alloway, Quinton, and 
  Delaware City.

This includes the following highways...
	New Jersey Turnpike near exit 1.
	Interstate 95 in Delaware between mile markers 1 and 22.
	Interstate 295 in New Jersey between mile markers 0 and 7.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3972 7579 3972 7577 3975 7576 3981 7569
      3983 7562 3984 7554 3983 7549 3980 7541
      3977 7546 3978 7542 3979 7541 3947 7536
      3945 7542 3938 7541 3938 7577

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

$$

Staarmann

2 follow-up statements

684 
WGUS71 KPHI 092218
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
618 PM EDT Sun Jul 9 2023

DEC003-NJC033-100045-
/O.CON.KPHI.FF.W.0046.000000T0000Z-230710T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Salem NJ-
618 PM EDT Sun Jul 9 2023

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 845 PM EDT THIS 
EVENING FOR NEW CASTLE AND WESTERN SALEM COUNTIES...

At 618 PM EDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain across the warned area. Between 1 
and 3.5 inches of rain have fallen. The expected rainfall rate is 
0.5 inches in 1 hour. Additional rainfall amounts up to 0.5 inches 
are possible in the warned area. 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...
  Wilmington, Newark, Middletown, Pennsville, Carneys Point, 
  Elsmere, New Castle, Penns Grove, Salem, Alloway, Quinton, and 
  Delaware City.

This includes the following highways...
	New Jersey Turnpike near exit 1.
	Interstate 95 in Delaware between mile markers 1 and 22.
	Interstate 295 in New Jersey between mile markers 0 and 7.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3972 7579 3972 7577 3975 7576 3981 7569
      3983 7562 3984 7554 3983 7549 3980 7541
      3977 7546 3978 7542 3979 7541 3947 7536
      3945 7542 3938 7541 3938 7577

FLASH FLOOD...RADAR AND GAUGE INDICATED
EXPECTED RAINFALL RATE...0.5 INCHES IN 1 HOUR

$$

Staarmann

603 
WGUS71 KPHI 100039
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
839 PM EDT Sun Jul 9 2023

DEC003-NJC033-100049-
/O.EXP.KPHI.FF.W.0046.000000T0000Z-230710T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Salem NJ-
839 PM EDT Sun Jul 9 2023

...FLASH FLOOD WARNING WILL EXPIRE AT 845 PM EDT THIS EVENING FOR 
NEW CASTLE AND WESTERN SALEM COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat.

A Flood Watch remains in effect until 1200 AM EDT for portions of 
east central Pennsylvania...northeast Pennsylvania...and southeast 
Pennsylvania.

A Flood Watch remains in effect until 1200 AM EDT for portions of 
northern Delaware...northeast Maryland...southern New Jersey...and 
southeast Pennsylvania.

A Flood Watch remains in effect until 1200 AM EDT for portions of 
Delaware...northeast Maryland...and southern New Jersey.

LAT...LON 3972 7579 3972 7577 3975 7576 3981 7569
      3983 7562 3984 7554 3983 7549 3980 7541
      3977 7546 3978 7542 3979 7541 3947 7536
      3945 7542 3938 7541 3938 7577

$$

Hoeflich

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 9, 4:01 PM EDT	Special Weather Statement	PHI	Kent	29 min
Jul 9, 4:16 PM EDT	Special Weather Statement	PHI	New Castle	29 min
Jul 9, 4:40 PM EDT	Areal Flood Advisory	PHI	New Castle	29 min
Jul 9, 4:40 PM EDT	Special Weather Statement	PHI	Kent	35 min
Jul 9, 4:46 PM EDT	Special Weather Statement	PHI	New Castle	29 min
Jul 9, 4:49 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	41 min
Jul 9, 5:01 PM EDT	Special Weather Statement	PHI	Kent, Sussex	29 min
Jul 9, 5:02 PM EDT	Areal Flood Advisory	PHI	Kent, New Castle	3 hr
Jul 9, 5:10 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	50 min
Jul 9, 5:31 PM EDT	Special Weather Statement	PHI	Sussex	29 min
Jul 9, 12:37 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Warren	2 hr
Jul 9, 1:02 PM EDT	Flash Flood Warning	PHI	Hunterdon, Warren	8 hr
Jul 9, 1:57 PM EDT	Areal Flood Advisory	PHI	Morris, Sussex, Warren	65 min
Jul 9, 2:05 PM EDT	Flash Flood Warning	PHI	Sussex	6 hr
Jul 9, 2:30 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Morris, Warren	4 min
Jul 9, 2:34 PM EDT	Flash Flood Warning	PHI	Hunterdon, Morris, Somerset, Warren	6 hr
Jul 9, 2:59 PM EDT	Special Weather Statement	PHI	Somerset	31 min
Jul 9, 3:00 PM EDT	Flash Flood Warning	PHI	Morris, Somerset, Sussex, Warren	6 hr
Jul 9, 4:12 PM EDT	Special Weather Statement	PHI	Somerset	33 min
Jul 9, 4:34 PM EDT	Special Marine Warning	PHI		86 min
Jul 9, 4:57 PM EDT	Special Marine Warning	PHI		93 min
Jul 9, 4:58 PM EDT	Special Weather Statement	PHI	Cumberland, Salem	47 min
Jul 9, 5:15 PM EDT	Special Weather Statement	PHI	Hunterdon, Warren	30 min
Jul 9, 5:35 PM EDT	Severe Thunderstorm Warning	PHI	Camden, Gloucester, Salem	25 min
Jul 9, 5:49 PM EDT	Special Weather Statement	PHI	Cumberland	26 min
Jul 9, 5:59 PM EDT	Flash Flood Warning	PHI	Hunterdon, Mercer	4 hr
Jul 9, 5:59 PM EDT	Special Weather Statement	PHI	Cape May	46 min
Jul 9, 6:33 PM EDT	Special Marine Warning	PHI		87 min
Jul 9, 6:52 PM EDT	Flash Flood Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset	4 hr
Jul 9, 7:11 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester, Mercer, Salem	3 hr
Jul 9, 7:16 PM EDT	Special Weather Statement	PHI	Burlington	29 min
Jul 9, 7:21 PM EDT	Special Marine Warning	PHI		114 min
Jul 9, 7:29 PM EDT	River Flood Warning	PHI	Hunterdon, Somerset	10 hr

Nearby

Flash Flood Warnings in Delaware, 2023 Flash Flood Warnings in New Jersey, 2023 Every 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.