Alert archive / Delaware / Flash Flood Warnings in 2025

Flash Flood Warning 54, NWS Philadelphia/Mount Holly

July 10, 2025Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 10, 2025, 7:33 PM EDT for Sussex County, Delaware. It was in force for 104 min. 1 report 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 10, 2025, 7:33 PM EDT (23:33 UTC)
Expired: Jul 10, 2025, 9:17 PM EDT
In force: 104 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 44 km from the middle of the area, began a volume at 23:34 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 10, 7:52 PM EDT	FLASH FLOOD	Bethany Beach, DE	DOT traffic camera shows water covering portions of Garfield Pkwy and Hollywood Street.

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, 11.6 hours before the alert went out and 72 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: 182 J/kg
Mixed-layer CIN: -90 J/kg
Mixed-layer LCL: 701 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 33 m²/s²
0-3 km storm-relative helicity: 38 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

995 
WGUS51 KPHI 102333
FFWPHI
DEC005-110345-
/O.NEW.KPHI.FF.W.0054.250710T2333Z-250711T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
733 PM EDT Thu Jul 10 2025

The National Weather Service in Mount Holly has issued a

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

* Until 1145 PM EDT.

* At 733 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 2.5 inches of 
  rain have fallen. The expected rainfall rate is 1 to 2 inches in 1 
  hour. 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...
  Millville, Ocean View and South Bethany.

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 3855 7514 3856 7505 3849 7504 3852 7513

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

$$

MJL

1 follow-up statement

295 
WGUS71 KPHI 110117
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
917 PM EDT Thu Jul 10 2025

DEC005-110127-
/O.CAN.KPHI.FF.W.0054.000000T0000Z-250711T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-
917 PM EDT Thu Jul 10 2025

...FLASH FLOOD WARNING FOR SOUTHEASTERN SUSSEX COUNTY HAS BEEN 
REPLACED WITH A FLOOD WARNING...

Heavy rainfall has ended and therefore the threat for flash flooding 
as ended. Water that remains on roadways will be slow to drain due 
to the high astronomical tide this evening. Please continue to heed 
remaining road closures.

&&

LAT...LON 3855 7514 3856 7505 3849 7504 3852 7513

$$

MJL

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 9, 8:00 PM EDT	Flash Flood Warning Considerable damage threat	PHI	New Castle	4 hr
Jul 9, 8:32 PM EDT	Flash Flood Warning Considerable damage threat	PHI	New Castle	4 hr
Jul 9, 8:46 PM EDT	Tornado Warning	PHI	New Castle	29 min
Jul 9, 8:51 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	39 min
Jul 9, 9:13 PM EDT	Tornado Warning	PHI	Sussex	32 min
Jul 9, 9:30 PM EDT	River Flood Warning	PHI	New Castle	7 hr
Jul 9, 11:27 PM EDT	River Flood Warning	PHI	New Castle	8 hr
Jul 9, 11:44 PM EDT	Areal Flood Warning	PHI	New Castle	4 hr
Jul 10, 4:15 PM EDT	Flash Flood Warning	PHI	Kent	117 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.