Alert archive / Delaware / Flash Flood Warnings in 2018

Flash Flood Warning 82, NWS Philadelphia/Mount Holly

August 31, 2018Kent County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 31, 2018, 11:31 AM EDT for Kent County, Delaware. It was in force for 11 hr. 2 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: Aug 31, 2018, 11:31 AM EDT (15:31 UTC)
Expired: Aug 31, 2018, 10:30 PM EDT
In force: 11 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Kent County, DE

The radar

The Dover AFB radar (KDOX), 24 km from the middle of the area, began a volume at 15:35 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
Aug 31, 4:42 PM EDT	FLASH FLOOD	1 Se Dover Speedway, DE	VIDEO SHOWS 1-2 FEET OF WATER RUNNING DOWN US 13/ NORTH DUNPORT HIGHWAY BETWEEN LAKEVIEW DRIVE AND WHITE OAK ROAD.
Aug 31, 6:13 PM EDT	HEAVY RAIN 5.45	Dover, DE	GAUGES SHOW RAINFALL BETWEEN 4 AND 5.5 INCHES AROUND DOVER. MOST OF THIS RAIN FELL BETWEEN NOON AND 6 PM.

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, 3.5 hours before the alert went out and 124 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: 72 J/kg
Mixed-layer CIN: -177 J/kg
Mixed-layer LCL: 1245 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 15 m²/s²
0-3 km storm-relative helicity: 89 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

The text

As transmitted.

988 
WGUS51 KPHI 311531
FFWPHI
DEC001-311830-
/O.NEW.KPHI.FF.W.0082.180831T1531Z-180831T1830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1131 AM EDT FRI AUG 31 2018

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Central Kent County in central Delaware...

* Until 230 PM EDT.

* At 1129 AM EDT, Doppler radar indicated over two inches of rain 
  has fallen in portions of eastern Kent County since earlier this 
  morning. With additional rain on the way, flash flooding is 
  expected. 

* Some locations that could experience flooding include...
  Dover, Camden, Cheswold, Bowers, Woodside, Viola, Rising
  Sun-Lebanon, Rising Sun, Dover Base Housing, Dover Speedway,
  Wyoming, Felton, Frederica, Magnolia, Little Creek, Leipsic, Rodney
  Village, Kent Acres, Riverview and Highland Acres.

LAT...LON 3893 7564 3925 7564 3927 7542 3910 7537
      3905 7537 3903 7534 3895 7532 3896 7539
      3895 7540

$$

jjm

3 follow-up statements

003 
WGUS51 KPHI 311812
FFWPHI
DEC001-312230-
/O.EXT.KPHI.FF.W.0082.000000T0000Z-180831T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
212 PM EDT FRI AUG 31 2018

The National Weather Service in Mount Holly NJ has extended the

* Flash Flood Warning for...
  Central Kent County in central Delaware...

* Until 630 PM EDT.

* At 209 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Up to 3 to 5 inches of rain 
  have fallen with earlier thunderstorms. Additional rainfall is 
  moving into the area which is expected to lead to additional Flash 
  flooding.

* Some locations that could experience flooding include...
  Dover, Camden, Cheswold, Bowers, Woodside, Viola, Rising
  Sun-Lebanon, Rising Sun, Dover Base Housing, Dover Speedway,
  Wyoming, Felton, Frederica, Magnolia, Little Creek, Leipsic, Rodney
  Village, Kent Acres, Riverview and Highland Acres.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3893 7564 3925 7564 3927 7542 3910 7537
      3905 7537 3903 7534 3895 7532 3896 7539
      3895 7540

$$

Robertson

007 
WGUS51 KPHI 312159
FFWPHI
DEC001-010230-
/O.EXT.KPHI.FF.W.0082.000000T0000Z-180901T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
559 PM EDT FRI AUG 31 2018

The National Weather Service in Mount Holly NJ has extended the

* Flash Flood Warning for...
  Central Kent County in central Delaware...

* Until 1030 PM EDT.

* At 557 PM EDT, the public reported flooding across the warned 
  area, in particular in and around Dover with flooded roadways due 
  to 4 to 6 inches of rainfall from earlier storms . Also, the St. 
  Johns River near Dover continues to rise and is expected to exceed 
  flood stage. Flash flooding is already occurring.

* Some locations that could experience flooding include...
  Dover, Camden, Cheswold, Bowers, Woodside, Viola, Rising
  Sun-Lebanon, Rising Sun, Dover Base Housing, Dover Speedway,
  Wyoming, Felton, Frederica, Magnolia, Little Creek, Leipsic, Rodney
  Village, Kent Acres, Riverview and Highland Acres.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3893 7564 3925 7564 3927 7542 3910 7537
      3905 7537 3903 7534 3895 7532 3896 7539
      3895 7540

$$

Robertson

391 
WGUS71 KPHI 010222
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1022 PM EDT FRI AUG 31 2018

DEC001-010231-
/O.EXP.KPHI.FF.W.0082.000000T0000Z-180901T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Kent DE-
1022 PM EDT FRI AUG 31 2018

...THE FLASH FLOOD WARNING FOR CENTRAL KENT COUNTY WILL EXPIRE AT
1030 PM EDT...

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

LAT...LON 3893 7564 3925 7564 3927 7542 3910 7537
      3905 7537 3903 7534 3895 7532 3896 7539
      3895 7540

$$

SFJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 31, 1:37 AM EDT	Special Weather Statement	PHI	Sussex	53 min
Aug 31, 10:57 AM EDT	Areal Flood Advisory	PHI	Kent	107 min
Aug 31, 11:53 AM EDT	Special Weather Statement	PHI	Kent	37 min
Aug 31, 12:00 PM EDT	Severe Thunderstorm Warning	PHI	Kent	15 min
Aug 31, 12:15 PM EDT	Flash Flood Warning	PHI	Kent, Sussex	7 hr
Aug 31, 12:28 PM EDT	Special Weather Statement	PHI	Kent	32 min
Aug 31, 12:35 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	40 min
Aug 31, 12:54 PM EDT	Flash Flood Warning	PHI	Sussex	4 hr
Aug 31, 1:09 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	51 min
Aug 31, 1:58 PM EDT	Special Weather Statement	PHI	Sussex	32 min
Aug 31, 4:27 PM EDT	Special Weather Statement	PHI	Sussex	18 min
Aug 31, 4:32 PM EDT	Flash Flood Warning	PHI	Sussex	4 hr
Aug 31, 4:41 PM EDT	Areal Flood Advisory	PHI	Kent, New Castle	4 hr
Aug 31, 4:42 PM EDT	Special Weather Statement	PHI	Sussex	33 min
Aug 31, 5:00 PM EDT	Flash Flood Warning	PHI	New Castle	4 hr
Aug 31, 5:14 PM EDT	Special Weather Statement	PHI	Sussex	46 min
Aug 31, 5:38 PM EDT	Areal Flood Advisory	PHI	Kent, New Castle, Sussex	4 hr
Aug 31, 5:48 PM EDT	Flash Flood Warning	PHI	Sussex	3 hr
Aug 31, 7:11 PM EDT	Areal Flood Warning	PHI	Kent, Sussex	4 hr
Aug 31, 7:37 PM EDT	Flash Flood Warning	PHI	Kent, New Castle	4 hr

Nearby

Flash Flood Warnings in Delaware, 2018 Every flash flood warning in 2018

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.