Alert archive / Delaware / Flash Flood Warnings in 2025

Flash Flood Warning 22, NWS Philadelphia/Mount Holly

June 29, 2025Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 29, 2025, 4:12 PM EDT for Sussex 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 29, 2025, 4:12 PM EDT (20:12 UTC)
Expired
Jun 29, 2025, 8:15 PM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 34 km from the middle of the area, began a volume at 20:14 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

TimeReportWhereRemark
Jun 29, 5:20 PM EDTFLASH FLOODBethany Beach, DESocial media video of multiple roads closed due to flooding at the intersection of Central Blvd and N Pennsylvania Ave. Time estimated from radar.
Jun 29, 6:00 PM EDTFLOODLong Neck, DESeveral public reports of flooding received from around Long Neck. One photo via social media showed about 1 foot of standing water along a residential street. Time estimated.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 8.2 hours before the alert went out and 78 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-pSkew-T log-p diagram, Wallops Is Stn, VA at 12:00Z on 2025-06-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2444 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Wallops Is Stn, VA at 12:00Z on 2025-06-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 29 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
2444 J/kg
Mixed-layer CIN
-19 J/kg
Mixed-layer LCL
829 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
29 m²/s²
0-3 km storm-relative helicity
22 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

155 
WGUS51 KPHI 292012
FFWPHI
DEC005-300015-
/O.NEW.KPHI.FF.W.0022.250629T2012Z-250630T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
412 PM EDT Sun Jun 29 2025

The National Weather Service in Mount Holly has issued a

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

* Until 815 PM EDT.

* At 412 PM EDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  0.5 and 2.5 inches of rain have fallen. The expected rainfall rate 
  is 1 to 3 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 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...
  Millsboro, Millville, Long Neck, Ocean View, 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 3870 7523 3872 7506 3861 7505 3849 7504
      3848 7512 3856 7521 3858 7528 3863 7529

FLASH FLOOD...RADAR AND GAUGE INDICATED
EXPECTED RAINFALL RATE...1-3 INCHES IN 1 HOUR

$$

Staarmann
3 follow-up statements
270 
WGUS71 KPHI 292102
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
502 PM EDT Sun Jun 29 2025

DEC005-300015-
/O.CON.KPHI.FF.W.0022.000000T0000Z-250630T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-
502 PM EDT Sun Jun 29 2025

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 PM EDT THIS 
EVENING FOR SOUTHEASTERN SUSSEX COUNTY...

At 502 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, with the greatest totals near 
Indian River Bay and Indian River Inlet. 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...
  Millsboro, Millville, Long Neck, Ocean View, Indian River Inlet, 
  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 3870 7523 3872 7506 3861 7505 3849 7504
      3848 7512 3856 7521 3858 7528 3863 7529

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

$$

Staarmann
564 
WGUS71 KPHI 292316
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
716 PM EDT Sun Jun 29 2025

DEC005-300015-
/O.CON.KPHI.FF.W.0022.000000T0000Z-250630T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-
716 PM EDT Sun Jun 29 2025

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 PM EDT THIS 
EVENING FOR SOUTHEASTERN SUSSEX COUNTY...

At 716 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, with the greatest totals near 
Indian River Bay and Indian River Inlet. Flash flooding is already 
occurring in Bethany Beach.

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...
  Millsboro, Millville, Long Neck, Ocean View, Indian River Inlet, 
  Bethany Beach, 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 3870 7523 3872 7506 3861 7505 3849 7504
      3848 7512 3856 7521 3858 7528 3863 7529

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

Staarmann
606 
WGUS71 KPHI 300006
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
806 PM EDT Sun Jun 29 2025

DEC005-300016-
/O.EXP.KPHI.FF.W.0022.000000T0000Z-250630T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-
806 PM EDT Sun Jun 29 2025

...FLASH FLOOD WARNING WILL EXPIRE AT 815 PM EDT THIS EVENING FOR 
SOUTHEASTERN SUSSEX COUNTY...

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

&&

LAT...LON 3870 7523 3872 7506 3861 7505 3849 7504
      3848 7512 3856 7521 3858 7528 3863 7529

$$

Staarmann

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 29, 2:21 AM EDTSevere Thunderstorm WarningPHIKent26 min
Jun 29, 6:21 PM EDTSevere Thunderstorm WarningPHISussex39 min
Jun 29, 6:52 PM EDTSevere Thunderstorm WarningPHISussex38 min

Nearby

Flash Flood Warnings in Delaware, 2025Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.