Alert archive / Delaware / Flash Flood Warnings in 2023

Flash Flood Warning 7, NWS Philadelphia/Mount Holly

June 23, 2023New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 23, 2023, 4:00 PM EDT for New Castle County, Delaware. It was in force for 4 hr. 2 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 23, 2023, 4:00 PM EDT (20:00 UTC)
Expired: Jun 23, 2023, 8:00 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County New Castle County, DE

The radar

The Dover AFB radar (KDOX), 76 km from the middle of the area, began a volume at 20:03 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
Jun 23, 4:23 PM EDT	FLASH FLOOD	1 Ssw Mcdonough, DE	Route 13 near Odessa has one lane closed in both directions near Shannon Cove Developments.
Jun 23, 4:23 PM EDT	FLASH FLOOD	1 Ssw Mcdonough, DE	Route 13 near Odessa has one lane closed in both directions near Shannon Cove Developments.

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, 8.0 hours before the alert went out and 162 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: 6 J/kg
Mixed-layer CIN: -203 J/kg
Mixed-layer LCL: 453 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 165 m²/s²
0-3 km storm-relative helicity: 180 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

629 
WGUS51 KPHI 232000
FFWPHI
DEC003-240000-
/O.NEW.KPHI.FF.W.0007.230623T2000Z-230624T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
400 PM EDT Fri Jun 23 2023

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Southwestern New Castle County in northern Delaware...

* Until 800 PM EDT.

* At 400 PM EDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  1.5 and 3 inches of rain have fallen. The expected rainfall rate 
  is 1 to 2 inches in 1 hour. Additional rainfall amounts of 1 to 2 
  inches are possible in the warned area. Flash flooding is ongoing 
  or expected to begin shortly. Flooding has already begun on 
  portions of US Route 13.

  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...
  Middletown, Delaware City, Mount Pleasant, Saint Georges, Port 
  Penn, Bear, Glasgow, Townsend, and Odessa.

Scattered showers and thunderstorms will continue impacting the 
warned area through this evening.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3932 7568 3933 7576 3962 7579 3964 7563
      3961 7557 3958 7554 3946 7558

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

$$

Staarmann

3 follow-up statements

086 
WGUS71 KPHI 232108
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
508 PM EDT Fri Jun 23 2023

DEC003-240000-
/O.CON.KPHI.FF.W.0007.000000T0000Z-230624T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-
508 PM EDT Fri Jun 23 2023

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 PM EDT THIS EVENING 
FOR SOUTHWESTERN NEW CASTLE COUNTY...

At 508 PM EDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain across the warned area. Between 
1.5 and 3 inches of rain have fallen. The expected rainfall rate is 
0.5 to 1 inch in 1 hour. Additional rainfall amounts of 0.5 to 1 
inch 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...
  Middletown, Delaware City, Mount Pleasant, Saint Georges, Port 
  Penn, Bear, Glasgow, Townsend, and Odessa.

Scattered showers and thunderstorms will continue impacting the 
warned area through this evening.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3932 7568 3933 7576 3962 7579 3964 7563
      3961 7557 3958 7554 3946 7558

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

$$

Staarmann

451 
WGUS71 KPHI 232302
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
702 PM EDT Fri Jun 23 2023

DEC003-240000-
/O.CON.KPHI.FF.W.0007.000000T0000Z-230624T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-
702 PM EDT Fri Jun 23 2023

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 PM EDT THIS EVENING 
FOR SOUTHWESTERN NEW CASTLE COUNTY...

At 702 PM EDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain across the warned area. Between 
1.5 and 3.5 inches of rain have fallen. 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...
  Middletown, Delaware City, Mount Pleasant, Saint Georges, Port 
  Penn, Bear, Glasgow, Townsend, and Odessa.

Scattered showers and thunderstorms will continue impacting the 
warned area through this evening.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3939 7564 3936 7576 3947 7577 3948 7578
      3951 7578 3956 7578 3962 7579 3964 7563
      3961 7557 3958 7554 3951 7556 3946 7558
      3945 7559

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

Staarmann

682 
WGUS71 KPHI 232351
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
751 PM EDT Fri Jun 23 2023

DEC003-240001-
/O.EXP.KPHI.FF.W.0007.000000T0000Z-230624T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-
751 PM EDT Fri Jun 23 2023

...FLASH FLOOD WARNING WILL EXPIRE AT 8 PM EDT THIS EVENING FOR 
SOUTHWESTERN NEW CASTLE COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Scattered showers and thunderstorms will remain possible 
overnight, which may result in additional minor flooding in urban 
and poor drainage areas.

LAT...LON 3939 7564 3936 7576 3947 7577 3948 7578
      3951 7578 3956 7578 3962 7579 3964 7563
      3961 7557 3958 7554 3951 7556 3946 7558
      3945 7559

$$

Staarmann

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 23, 2:08 PM EDT	Special Weather Statement	PHI	Kent	37 min
Jun 23, 2:39 PM EDT	Special Weather Statement	PHI	Kent	36 min
Jun 23, 2:58 PM EDT	Areal Flood Advisory	PHI	New Castle	83 min
Jun 23, 3:50 PM EDT	Areal Flood Advisory	PHI	New Castle	30 min
Jun 23, 4:19 PM EDT	Flash Flood Warning	PHI	New Castle	4 hr

Nearby

Flash Flood Warnings in Delaware, 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.