Alert archive / Delaware / Flash Flood Warnings in 2024

Flash Flood Warning 66, NWS Philadelphia/Mount Holly

August 29, 2024New Castle County, Delaware; Delaware County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 29, 2024, 11:14 PM EDT for New Castle County, Delaware; Delaware County, Pennsylvania. 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
Aug 29, 2024, 11:14 PM EDT (03:14 UTC)
Expired
Aug 30, 2024, 2:00 AM EDT
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties New Castle County, DE, Delaware County, PA

The radar

The Philadelphia radar (KDIX), 99 km from the middle of the area, began a volume at 03:17 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, 3.2 hours before the alert went out and 204 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 00:00Z on 2024-08-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 851 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 00:00Z on 2024-08-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 118 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
851 J/kg
Mixed-layer CIN
-43 J/kg
Mixed-layer LCL
497 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
118 m²/s²
0-3 km storm-relative helicity
135 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.7

Open this sounding in Storm Lab

The text

As transmitted.

923 
WGUS51 KPHI 300314
FFWPHI
DEC003-PAC045-300615-
/O.NEW.KPHI.FF.W.0066.240830T0314Z-240830T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1114 PM EDT Thu Aug 29 2024

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northern New Castle County in northern Delaware...
  Southwestern Delaware County in southeastern Pennsylvania...

* Until 215 AM EDT.

* At 1114 PM EDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  0.5 and 1 inch of rain has 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 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...
  Wilmington, Newark, Chester, Elsmere, New Castle, Newport, Arden, 
  Greenville, Wilmington Manor, Talleyville, Stanton and Ashland.

This includes the following highways...
	Interstate 95 in Pennsylvania between mile markers 0 and 1.
	Interstate 95 in Delaware between mile markers 5 and 23.

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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3984 7560 3985 7556 3983 7539 3979 7543
      3978 7544 3977 7545 3977 7546 3976 7546
      3975 7547 3966 7556 3962 7562 3964 7565
      3967 7573 3982 7567 3984 7561

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

Wunderlin
2 follow-up statements
745 
WGUS71 KPHI 300446
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1246 AM EDT Fri Aug 30 2024

DEC003-PAC045-300615-
/O.CON.KPHI.FF.W.0066.000000T0000Z-240830T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Delaware PA-
1246 AM EDT Fri Aug 30 2024

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 215 AM EDT EARLY THIS 
MORNING FOR NORTHERN NEW CASTLE AND SOUTHWESTERN DELAWARE COUNTIES...

At 1246 AM EDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain have mostly moved out of the 
warned area. However, it will take some time for waters to recede. 
Between 1 and 2 inches of rain have fallen. Additional rainfall 
amounts up to 0.5 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...
  Wilmington, Newark, Chester, Elsmere, New Castle, Newport, Arden, 
  Greenville, Wilmington Manor, Talleyville, Stanton and Ashland.

This includes the following highways...
	Interstate 95 in Pennsylvania between mile markers 0 and 1.
	Interstate 95 in Delaware between mile markers 5 and 23.

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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3984 7560 3985 7556 3983 7539 3979 7543
      3978 7544 3977 7545 3977 7546 3976 7546
      3975 7547 3966 7556 3962 7562 3964 7565
      3967 7573 3982 7567 3984 7561

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

Wunderlin
158 
WGUS71 KPHI 300600
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
200 AM EDT Fri Aug 30 2024

DEC003-PAC045-300610-
/O.CAN.KPHI.FF.W.0066.000000T0000Z-240830T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Delaware PA-
200 AM EDT Fri Aug 30 2024

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHERN NEW CASTLE AND 
SOUTHWESTERN DELAWARE 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 3984 7560 3985 7556 3983 7539 3979 7543
      3978 7544 3977 7545 3977 7546 3976 7546
      3975 7547 3966 7556 3962 7562 3964 7565
      3967 7573 3982 7567 3984 7561

$$

Wunderlin

Nearby

Flash Flood Warnings in Delaware, 2024Flash Flood Warnings in Pennsylvania, 2024Every flash flood warning in 2024

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.