Alert archive / Delaware / Flash Flood Warnings in 2021
Flash Flood Warning 38, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 17, 2021, 2:49 PM EDT for Kent County, New Castle County, Delaware. It was in force for 91 min. 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 17, 2021, 2:49 PM EDT (18:49 UTC)
- Expired
- Aug 17, 2021, 4:20 PM EDT
- In force
- 91 min
- 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), 54 km from the middle of the area, began a volume at 18:51 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 12:00Z, 6.8 hours before the alert went out and 153 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.
- Mixed-layer CAPE
- 478 J/kg
- Mixed-layer CIN
- -25 J/kg
- Mixed-layer LCL
- 753 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- 34 m²/s²
- 0-3 km storm-relative helicity
- 48 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted.
425
WGUS51 KPHI 171849
FFWPHI
DEC001-003-172300-
/O.NEW.KPHI.FF.W.0038.210817T1849Z-210817T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
249 PM EDT Tue Aug 17 2021
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Northern Kent County in central Delaware...
Southwestern New Castle County in northern Delaware...
* Until 700 PM EDT.
* At 249 PM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 2 and 3 inches of rain
have already fallen in aprts of the area. 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 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 will experience flash flooding include...
Dover, Smyrna, Clayton, Cheswold, Green Spring, Woodland Beach,
Delaney Corner, Townsend, Kenton, Leipsic, and Chambersville.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Motorists should not attempt to drive around barricades or drive
cars through flooded areas.
&&
LAT...LON 3940 7577 3940 7550 3935 7547 3931 7542
3926 7540 3924 7539 3919 7538 3920 7575
FLASH FLOOD...RADAR INDICATED
$$
Iovino1 follow-up statement
857
WGUS71 KPHI 172020
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
420 PM EDT Tue Aug 17 2021
DEC001-003-172030-
/O.CAN.KPHI.FF.W.0038.000000T0000Z-210817T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kent DE-New Castle DE-
420 PM EDT Tue Aug 17 2021
...FLASH FLOOD WARNING IS CANCELLED FOR NORTHERN KENT AND
SOUTHWESTERN NEW CASTLE COUNTIES...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
LAT...LON 3940 7577 3940 7550 3935 7547 3931 7542
3926 7540 3924 7539 3919 7538 3920 7575
$$
IovinoThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 17, 12:11 PM EDT | Areal Flood Advisory | PHI | New Castle | 3 hr |
| Aug 17, 1:25 PM EDT | Areal Flood Advisory | PHI | Kent, New Castle | 3 hr |
| Aug 17, 1:31 PM EDT | Areal Flood Advisory | PHI | Sussex | 3 hr |
| Aug 17, 1:46 PM EDT | River Flood Warning | PHI | New Castle | 3 hr |
| Aug 17, 1:56 PM EDT | Flash Flood Warning | PHI | New Castle | 4 hr |
| Aug 17, 2:06 PM EDT | River Flood Warning | PHI | New Castle | 4 hr |
Nearby
Flash Flood Warnings in Delaware, 2021Every flash flood warning in 2021
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.