Alert archive / Delaware / Flash Flood Warnings in 2026

Flash Flood Warning 61, NWS Philadelphia/Mount Holly

July 21, 2026Kent County, New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 21, 2026, 6:53 PM EDT for Kent County, New Castle 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: Jul 21, 2026, 6:53 PM EDT (22:53 UTC)
Expired: Jul 21, 2026, 9:48 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Kent County, DE, New Castle County, DE

The radar

The Dover AFB radar (KDOX), 71 km from the middle of the area, began a volume at 22:55 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.9 hours before the alert went out and 165 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: 941 J/kg
Mixed-layer CIN: -113 J/kg
Mixed-layer LCL: 772 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 68 m²/s²
0-3 km storm-relative helicity: 112 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 0.9

Open this sounding in Storm Lab

The text

As transmitted.

203 
WGUS51 KPHI 212253
FFWPHI
DEC001-003-220300-
/O.NEW.KPHI.FF.W.0061.260721T2253Z-260722T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
653 PM EDT Tue Jul 21 2026

The National Weather Service in Mount Holly has issued a

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

* Until 1100 PM EDT.

* At 653 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 0.5 to 1.5 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...
  Middletown, Smyrna, Clayton, Delaware City, Mount Pleasant, Green 
  Spring, Port Penn, Saint Georges, Delaney Corner, Bear, Glasgow 
  and Townsend.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3961 7560 3958 7556 3948 7556 3935 7548
      3932 7548 3927 7557 3926 7576 3961 7579

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...0.5-1.5 INCHES IN 1 HOUR

$$

Hoeflich

1 follow-up statement

181 
WGUS71 KPHI 220148
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
948 PM EDT Tue Jul 21 2026

DEC001-003-220158-
/O.CAN.KPHI.FF.W.0061.000000T0000Z-260722T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kent DE-New Castle DE-
948 PM EDT Tue Jul 21 2026

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHWESTERN KENT AND 
SOUTHWESTERN NEW CASTLE COUNTIES...

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 3961 7560 3958 7556 3948 7556 3935 7548
      3932 7548 3927 7557 3926 7576 3961 7579

$$

Hoeflich

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 3:58 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	47 min
Jul 21, 4:38 PM EDT	Flash Flood Warning Considerable damage threat	PHI	New Castle	4 hr
Jul 21, 4:43 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	47 min
Jul 21, 5:06 PM EDT	Severe Thunderstorm Warning	PHI	Kent	39 min
Jul 21, 5:30 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	45 min
Jul 21, 5:42 PM EDT	Severe Thunderstorm Warning Considerable damage threat	PHI	Kent	48 min
Jul 21, 6:00 PM EDT	Severe Thunderstorm Warning	PHI	Kent, New Castle	45 min

Nearby

Flash Flood Warnings in Delaware, 2026 Every flash flood warning in 2026

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.