Alert archive / Delaware / Flash Flood Warnings in 2025

Flash Flood Warning 24, NWS Philadelphia/Mount Holly

June 30, 2025Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 30, 2025, 1:34 PM EDT for Sussex County, Delaware. 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: Jun 30, 2025, 1:34 PM EDT (17:34 UTC)
Expired: Jun 30, 2025, 4:12 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Sussex County, DE

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 5.6 hours before the alert went out and 75 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: 2301 J/kg
Mixed-layer CIN: -34 J/kg
Mixed-layer LCL: 947 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 11 m²/s²
0-3 km storm-relative helicity: 19 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.6

Open this sounding in Storm Lab

The text

As transmitted.

040 
WGUS51 KPHI 301734
FFWPHI
DEC005-302145-
/O.NEW.KPHI.FF.W.0024.250630T1734Z-250630T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
134 PM EDT Mon Jun 30 2025

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Southeastern Sussex County in southern Delaware...

* Until 545 PM EDT.

* At 134 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2.5 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.

  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...
  Millsboro, Selbyville, Dagsboro, Millville, Henlopen Acres, Long 
  Neck, Ocean View, Frankford, South Bethany and Dewey Beach.

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 3845 7505 3845 7508 3845 7509 3845 7521
      3848 7530 3866 7530 3874 7522 3875 7516
      3872 7509 3871 7503 3868 7502 3862 7501
      3854 7499 3845 7501 3845 7503 3846 7505

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

$$

Hoeflich

3 follow-up statements

790 
WGUS71 KPHI 301800
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
200 PM EDT Mon Jun 30 2025

DEC005-302145-
/O.CON.KPHI.FF.W.0024.000000T0000Z-250630T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-
200 PM EDT Mon Jun 30 2025

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 545 PM EDT THIS 
AFTERNOON FOR SOUTHEASTERN SUSSEX COUNTY...

At 200 PM EDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 2 and 3 inches of rain have 
fallen. The expected rainfall rate is 1 to 2 inches in 1 hour. 
Additional rainfall amounts of 1.5 to 3 inches are possible in the 
warned area. Flash flooding is ongoing or expected to begin shortly.

HAZARD...Life threatening flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets, and underpasses.

Some locations that may experience flash flooding include...
  Millsboro, Selbyville, Dagsboro, Millville, Henlopen Acres, Long 
  Neck, Ocean View, Frankford, South Bethany and Dewey Beach.

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 3845 7505 3845 7508 3845 7509 3845 7521
      3848 7530 3866 7530 3874 7522 3875 7516
      3872 7509 3871 7503 3868 7502 3862 7501
      3854 7499 3845 7501 3845 7503 3846 7505

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

$$

Hoeflich

006 
WGUS71 KPHI 301910
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
310 PM EDT Mon Jun 30 2025

DEC005-302145-
/O.CON.KPHI.FF.W.0024.000000T0000Z-250630T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-
310 PM EDT Mon Jun 30 2025

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 545 PM EDT THIS 
AFTERNOON FOR SOUTHEASTERN SUSSEX COUNTY...

At 310 PM EDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 2 and 4 inches of rain have 
fallen. Flooding impacts will continue, but no additional rainfall 
is expected. 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...
  Millsboro, Selbyville, Dagsboro, Millville, Henlopen Acres, Long 
  Neck, Ocean View, Frankford, South Bethany and Dewey Beach.

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 3845 7505 3845 7508 3845 7509 3845 7521
      3848 7530 3866 7530 3874 7522 3875 7516
      3872 7509 3871 7503 3868 7502 3862 7501
      3854 7499 3845 7501 3845 7503 3846 7505

FLASH FLOOD...RADAR INDICATED

$$

Hoeflich

851 
WGUS71 KPHI 302012
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
412 PM EDT Mon Jun 30 2025

DEC005-302022-
/O.CAN.KPHI.FF.W.0024.000000T0000Z-250630T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-
412 PM EDT Mon Jun 30 2025

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN SUSSEX COUNTY...

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.

&&

LAT...LON 3845 7505 3845 7508 3845 7509 3845 7521
      3848 7530 3866 7530 3874 7522 3875 7516
      3872 7509 3871 7503 3868 7502 3862 7501
      3854 7499 3845 7501 3845 7503 3846 7505

$$

Hoeflich

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 30, 3:19 AM EDT	Heat Advisory	PHI	New Castle	13 hr
Jun 30, 1:16 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	44 min
Jun 30, 1:28 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	47 min
Jun 30, 1:55 PM EDT	Flash Flood Warning	PHI	New Castle	4 hr
Jun 30, 3:52 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	38 min

Nearby

Flash Flood Warnings in Delaware, 2025 Every flash flood warning in 2025

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.