Alert archive / Delaware / Flash Flood Warnings in 2025

Flash Flood Warning 73, NWS Philadelphia/Mount Holly

July 16, 2025New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 16, 2025, 10:43 PM EDT for New Castle County, Delaware. It was in force for 2 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: Jul 16, 2025, 10:43 PM EDT (02:43 UTC)
Expired: Jul 17, 2025, 12:53 AM EDT
In force: 2 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), 96 km from the middle of the area, began a volume at 02:46 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.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 00:00Z, 2.7 hours before the alert went out and 195 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: 2034 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 865 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 72 m²/s²
0-3 km storm-relative helicity: 107 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

191 
WGUS51 KPHI 170243
FFWPHI
DEC003-170645-
/O.NEW.KPHI.FF.W.0073.250717T0243Z-250717T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1043 PM EDT Wed Jul 16 2025

The National Weather Service in Mount Holly has issued a

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

* Until 245 AM EDT.

* At 1043 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1.5 inches of 
  rain have fallen. 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...
  Wilmington, Newark, Middletown, Carneys Point, Elsmere, New 
  Castle, Penns Grove, Delaware City, Newport, Bear, Saint Georges 
  and Wilmington Manor.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3972 7579 3972 7577 3977 7575 3980 7542
      3977 7546 3974 7547 3963 7557 3943 7554
      3943 7577

FLASH FLOOD...RADAR INDICATED

$$

AKL

1 follow-up statement

052 
WGUS71 KPHI 170453
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1253 AM EDT Thu Jul 17 2025

DEC003-170503-
/O.CAN.KPHI.FF.W.0073.000000T0000Z-250717T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-
1253 AM EDT Thu Jul 17 2025

...FLASH FLOOD WARNING IS CANCELLED FOR NEW CASTLE COUNTY...

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

A Flood Watch remains in effect until 300 AM EDT for portions of 
east central, northeast, and southeast Pennsylvania.

A Flood Watch remains in effect until 300 AM EDT for portions of 
northern Delaware and southern New Jersey.

&&

LAT...LON 3972 7579 3972 7577 3977 7575 3980 7542
      3977 7546 3974 7547 3963 7557 3943 7554
      3943 7577

$$

Staarmann

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 16, 10:44 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	46 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; radar from the NEXRAD Level II archive.