Alert archive / Delaware / Flash Flood Warnings in 2020

Flash Flood Warning 5, NWS Philadelphia/Mount Holly

June 11, 2020Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 11, 2020, 7:58 PM EDT for Sussex County, Delaware. It was in force for 4 hr. 4 reports 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: Jun 11, 2020, 7:58 PM EDT (23:58 UTC)
Expired: Jun 11, 2020, 11:29 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 16 km from the middle of the area, began a volume at 00:03 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
Jun 11, 8:26 PM EDT	HEAVY RAIN 1.69	3.9 Se Milton, DE	STORM TOTAL SO FAR. 1.28 INCHES IN 70 MINUTES.
Jun 11, 9:15 PM EDT	FLOOD	1 W Seaford, DE	PORTER STREET CLOSED DUE TO FLOODING.
Jun 11, 9:19 PM EDT	HEAVY RAIN 3.58	Milton, DE	PERSONAL WEATHER STATION KDEMILTO18.
Jun 11, 9:30 PM EDT	FLOOD	Georgetown, DE	A FEW REPORTS OF STREET FLOODING IN GEORGETOWN. MAINLY MINOR FLOODING IN SUSCEPTIBLE POOR DRAINAGE AREAS.

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

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 12.0 hours before the alert went out and 85 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 586 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 93 m²/s²
0-3 km storm-relative helicity: 90 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

795 
WGUS51 KPHI 112358
FFWPHI
DEC005-120400-
/O.NEW.KPHI.FF.W.0005.200611T2358Z-200612T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
758 PM EDT Thu Jun 11 2020

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Central Sussex County in southern Delaware...

* Until midnight EDT.

* At 757 PM EDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to two inches of rain have
  already fallen. Flash flooding is ongoing or expected to begin
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  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 could experience flooding include...
  Georgetown, Seaford, Laurel, Lewes, Milton, Henlopen Acres,
  Sycamore, Cape Henlopen State Park, Blades and Bethel.

Additional rainfall amounts of one to two inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3849 7570 3865 7571 3887 7524 3879 7515
      3881 7509 3873 7506

FLASH FLOOD...RADAR INDICATED

$$

Staarmann

2 follow-up statements

552 
WGUS71 KPHI 120125
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
925 PM EDT Thu Jun 11 2020

DEC005-120400-
/O.CON.KPHI.FF.W.0005.000000T0000Z-200612T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX DE-
925 PM EDT Thu Jun 11 2020

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL MIDNIGHT EDT FOR
CENTRAL SUSSEX COUNTY...

At 923 PM EDT gauge reports and radar estimates indicated excessive 
rainfall causing flash flooding over the warned area. Over three 
inches of rain have fallen in some areas. Flash flooding is ongoing 
or expected to begin shortly.

HAZARD...Flash flooding from excessive rain.

SOURCE...Gauges indicated.

IMPACT...Flooding of small creeks and streams, urban areas, 
         highways, streets and underpasses as well as other drainage 
         and low lying areas.

Locations impacted include...
Georgetown, Seaford, Laurel, Lewes, Milton, Henlopen Acres, Sycamore,
Cape Henlopen State Park, Blades and Bethel.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3849 7570 3865 7571 3887 7524 3879 7515
      3881 7509 3873 7506

FLASH FLOOD...GAUGE INDICATED

$$

JEO

261 
WGUS71 KPHI 120329
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1129 PM EDT Thu Jun 11 2020

DEC005-120339-
/O.CAN.KPHI.FF.W.0005.000000T0000Z-200612T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-
1129 PM EDT Thu Jun 11 2020

...THE FLASH FLOOD WARNING FOR CENTRAL SUSSEX COUNTY IS CANCELLED...

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

LAT...LON 3849 7570 3865 7571 3887 7524 3879 7515
      3881 7509 3873 7506

$$

BAH

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 11, 3:16 AM EDT	Rip Current Statement	PHI	Sussex	18 hr
Jun 11, 6:35 PM EDT	Areal Flood Advisory	PHI	Sussex	115 min
Jun 11, 7:27 PM EDT	Special Weather Statement	PHI	Sussex	33 min
Jun 11, 7:41 PM EDT	Areal Flood Advisory	PHI	Sussex	2 hr

Nearby

Flash Flood Warnings in Delaware, 2020 Every flash flood warning in 2020

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.