Alert archive / Delaware / Flash Flood Warnings in 2025

Flash Flood Warning 13, NWS Philadelphia/Mount Holly

May 30, 2025New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at May 30, 2025, 10:26 PM EDT for New Castle County, Delaware. It was in force for 4 hr. 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: May 30, 2025, 10:26 PM EDT (02:26 UTC)
Expired: May 31, 2025, 2:30 AM EDT
In force: 4 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), 97 km from the middle of the area, began a volume at 02:25 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
May 31, 12:00 AM EDT	FLASH FLOOD	1 Sse Glasgow, DE	Multiple reports of flooding along Old Baltimore Pike from Middletown, DE up through Newark, DE.

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

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 2.4 hours before the alert went out and 176 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: 926 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 804 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 128 m²/s²
0-3 km storm-relative helicity: 146 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 5.5

Open this sounding in Storm Lab

The text

As transmitted.

948 
WGUS51 KPHI 310226
FFWPHI
DEC003-310630-
/O.NEW.KPHI.FF.W.0013.250531T0226Z-250531T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1026 PM EDT Fri May 30 2025

The National Weather Service in Mount Holly has issued a

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

* Until 230 AM EDT.

* At 1026 PM EDT, Doppler radar indicated heavy rain across the 
  warned area. Between 0.5 and 1 inch of rain has fallen. The 
  expected rainfall rate is 1 to 2 inches in 1 hour. Additional 
  rainfall amounts of 1 to 3 inches are possible in the warned area. 
  Flash flooding is ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by heavy rain.

  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, Arden, Bear and Saint 
  Georges.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3939 7557 3941 7577 3972 7579 3972 7577
      3976 7575 3979 7572 3982 7566 3984 7559
      3983 7551 3982 7544 3981 7543 3980 7543
      3977 7546 3974 7547 3968 7553 3965 7557
      3964 7559 3949 7557

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

$$

Hoeflich

2 follow-up statements

701 
WGUS71 KPHI 310421
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1221 AM EDT Sat May 31 2025

DEC003-310630-
/O.CON.KPHI.FF.W.0013.000000T0000Z-250531T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-
1221 AM EDT Sat May 31 2025

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 230 AM EDT EARLY THIS 
MORNING FOR NEW CASTLE COUNTY...

At 1221 AM EDT, emergency management reported heavy rain with 
multiple reports of flooding along Old Baltimore Pike from 
Middletown, DE up through Newark, DE. Between 1.5 and 2.5 inches of 
rain have fallen. Additional rainfall amounts up to 0.5 inches are 
possible in the warned area. Flash flooding is already occurring.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Emergency management reported.

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, Arden, Bear and Saint 
  Georges.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3939 7557 3941 7577 3972 7579 3972 7577
      3976 7575 3979 7572 3982 7566 3984 7559
      3983 7551 3982 7544 3981 7543 3980 7543
      3977 7546 3974 7547 3968 7553 3965 7557
      3964 7559 3949 7557

FLASH FLOOD...OBSERVED

$$

Hoeflich

943 
WGUS71 KPHI 310621
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
221 AM EDT Sat May 31 2025

DEC003-310631-
/O.EXP.KPHI.FF.W.0013.000000T0000Z-250531T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-
221 AM EDT Sat May 31 2025

...FLASH FLOOD WARNING WILL EXPIRE AT 230 AM EDT EARLY THIS MORNING 
FOR NEW CASTLE COUNTY...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

A Flood Watch remains in effect until 800 AM EDT for portions of 
northern Delaware and Pennsylvania.

A Flood Watch remains in effect until 800 AM EDT for portions of 
central, northern, northwest, and southern New Jersey.

&&

LAT...LON 3939 7557 3941 7577 3972 7579 3972 7577
      3976 7575 3979 7572 3982 7566 3984 7559
      3983 7551 3982 7544 3981 7543 3980 7543
      3977 7546 3974 7547 3968 7553 3965 7557
      3964 7559 3949 7557

$$

Hoeflich

The office that day

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

Issued	Product	Office	Counties	Lasted
May 30, 9:04 PM EDT	Wind Advisory	PHI	Kent, New Castle, Sussex	10 hr
May 30, 10:26 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	49 min
May 30, 10:55 PM EDT	Tornado Warning	PHI	New Castle	22 min
May 31, 1:17 PM EDT	Severe Thunderstorm Warning	PHI	Kent	43 min
May 31, 1:30 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	45 min
May 31, 1:42 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	48 min
May 31, 2:00 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	45 min
May 31, 2:26 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	49 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.