Alert archive / Delaware / Flash Flood Warnings in 2018

Flash Flood Warning 83, NWS Philadelphia/Mount Holly

August 31, 2018Kent County, Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 31, 2018, 12:15 PM EDT for Kent County, Sussex County, Delaware. It was in force for 7 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
Aug 31, 2018, 12:15 PM EDT (16:15 UTC)
Expired
Aug 31, 2018, 7:15 PM EDT
In force
7 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Kent County, DE, Sussex County, DE

The radar

The Dover AFB radar (KDOX), 10 km from the middle of the area, began a volume at 16:16 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

TimeReportWhereRemark
Aug 31, 1:00 PM EDTFLASH FLOODMilford, DESEVERAL ROADWAYS AND INTERSECTIONS WERE CLOSED DUE TO FLOODING.

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, 4.3 hours before the alert went out and 110 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 12:00Z on 2018-08-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 72 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 12:00Z on 2018-08-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 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
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.

771 
WGUS51 KPHI 311615
FFWPHI
DEC001-005-311915-
/O.NEW.KPHI.FF.W.0083.180831T1615Z-180831T1915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1215 PM EDT FRI AUG 31 2018

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  North central Sussex County in southern Delaware...
  Southeastern Kent County in central Delaware...

* Until 315 PM EDT.

* At 1214 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between one and two inches of 
  rain has been estimated by radar during the past hour...and 
  additional rain is on the way.

* Some locations that could experience flooding include...
  Milford, Harrington, Houston and Farmington. 

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 3898 7534 3886 7526 3881 7555 3895 7565

$$

jjm
2 follow-up statements
768 
WGUS51 KPHI 311905
FFWPHI
DEC001-005-312315-
/O.EXT.KPHI.FF.W.0083.000000T0000Z-180831T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Mount Holly NJ has extended the

* Flash Flood Warning for...
  North central Sussex County in southern Delaware...
  Southeastern Kent County in central Delaware...

* Until 715 PM EDT.

* At 303 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...
  Milford, Harrington, Houston and Farmington. 

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 3898 7534 3886 7526 3881 7555 3895 7565

$$

Robertson
225 
WGUS71 KPHI 312308
FFSPHI

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

DEC001-005-312315-
/O.EXP.KPHI.FF.W.0083.000000T0000Z-180831T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-Kent DE-
708 PM EDT FRI AUG 31 2018

...THE FLASH FLOOD WARNING FOR NORTH CENTRAL SUSSEX AND SOUTHEASTERN
KENT COUNTIES WILL EXPIRE AT 715 PM EDT...

The heavy rain has ended. Flash Flooding is no longer expected to 
pose a threat, however, many local creeks and stream continue to run 
high and there continues to be some roadway flooding. An Areal Flood 
Warning will be issued for any residual flooding. There will 
continue to be scattered showers through this evening. Please 
continue to heed any remaining road closures.

LAT...LON 3898 7534 3886 7526 3881 7555 3895 7565

$$

Robertson

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 31, 1:37 AM EDTSpecial Weather StatementPHISussex53 min
Aug 31, 10:57 AM EDTAreal Flood AdvisoryPHIKent107 min
Aug 31, 11:31 AM EDTFlash Flood WarningPHIKent11 hr
Aug 31, 11:53 AM EDTSpecial Weather StatementPHIKent37 min
Aug 31, 12:00 PM EDTSevere Thunderstorm WarningPHIKent15 min
Aug 31, 12:28 PM EDTSpecial Weather StatementPHIKent32 min
Aug 31, 12:35 PM EDTSevere Thunderstorm WarningPHIKent, Sussex40 min
Aug 31, 12:54 PM EDTFlash Flood WarningPHISussex4 hr
Aug 31, 1:09 PM EDTSevere Thunderstorm WarningPHISussex51 min
Aug 31, 1:58 PM EDTSpecial Weather StatementPHISussex32 min
Aug 31, 4:27 PM EDTSpecial Weather StatementPHISussex18 min
Aug 31, 4:32 PM EDTFlash Flood WarningPHISussex4 hr
Aug 31, 4:41 PM EDTAreal Flood AdvisoryPHIKent, New Castle4 hr
Aug 31, 4:42 PM EDTSpecial Weather StatementPHISussex33 min
Aug 31, 5:00 PM EDTFlash Flood WarningPHINew Castle4 hr
Aug 31, 5:14 PM EDTSpecial Weather StatementPHISussex46 min
Aug 31, 5:38 PM EDTAreal Flood AdvisoryPHIKent, New Castle, Sussex4 hr
Aug 31, 5:48 PM EDTFlash Flood WarningPHISussex3 hr
Aug 31, 7:11 PM EDTAreal Flood WarningPHIKent, Sussex4 hr
Aug 31, 7:37 PM EDTFlash Flood WarningPHIKent, New Castle4 hr

Nearby

Flash Flood Warnings in Delaware, 2018Every 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.