Alert archive / Delaware / Flash Flood Warnings in 2018

Flash Flood Warning 12, NWS Philadelphia/Mount Holly

June 9, 2018Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 9, 2018, 2:53 PM EDT for Sussex County, Delaware. It was in force for 4 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
Jun 9, 2018, 2:53 PM EDT (18:53 UTC)
Expired
Jun 9, 2018, 6:45 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), 18 km from the middle of the area, began a volume at 18:54 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
Jun 9, 3:30 PM EDTFLASH FLOODSeaford, DE911 CENTER REPORTS SEVERALS CARS FLOODED IN WATER AND IMPASSABLE ROADS DUE TO FLOODING IN AND AROUND TOWN WITHIN THE LAST 1-2 HOURS

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, 6.9 hours before the alert went out and 87 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 2018-06-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 733 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 2018-06-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 60 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
733 J/kg
Mixed-layer CIN
-48 J/kg
Mixed-layer LCL
972 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
60 m²/s²
0-3 km storm-relative helicity
51 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

531 
WGUS51 KPHI 091853
FFWPHI
DEC005-092245-
/O.NEW.KPHI.FF.W.0012.180609T1853Z-180609T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
253 PM EDT SAT JUN 9 2018

The National Weather Service in Mount Holly NJ has issued a

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

* Until 645 PM EDT.

* At 251 PM EDT, Doppler radar indicated thunderstorms moving slowly 
  east into western Sussex County. Rainfall rates between one and 
  two inches of rain per hour have been reported, and flash flooding 
  is expected in the heavier downpours.
  
 
* Some locations that could experience flooding include...
  Georgetown, Milford, Seaford, Laurel, Bridgeville, Ellendale,
  Sycamore, Blades, Greenwood and Bethel.

LAT...LON 3849 7569 3883 7572 3884 7555 3889 7551
      3891 7541 3847 7541

$$

JJM
2 follow-up statements
122 
WGUS71 KPHI 092012
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
412 PM EDT SAT JUN 9 2018

DEC005-092245-
/O.CON.KPHI.FF.W.0012.000000T0000Z-180609T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-
412 PM EDT SAT JUN 9 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 645 PM EDT FOR
SOUTHWESTERN SUSSEX COUNTY...

At 411 PM EDT, Doppler radar indicated thunderstorms producing heavy 
rain continue across the warned area.  Flash flooding is expected to 
continue through the afternoon hours. 

Some locations that could experience flooding include...
Seaford, Laurel, Sycamore, Blades and Bethel. 

LAT...LON 3865 7570 3865 7541 3847 7541 3849 7569

$$

jjm
416 
WGUS71 KPHI 092246
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
646 PM EDT SAT JUN 9 2018

DEC005-092254-
/O.EXP.KPHI.FF.W.0012.000000T0000Z-180609T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-
646 PM EDT SAT JUN 9 2018

...THE FLASH FLOOD WARNING FOR SOUTHWESTERN SUSSEX COUNTY WILL EXPIRE
AT 645 PM EDT...

The risk of life-threatening flash flooding has decreased since this 
afternoon. However, excessive runoff from the heavy rain that 
already fell and an additional one-half to one inch of rainfall that 
is expected early this evening will continue to cause areal flooding 
along creeks and streams and in poor drainage areas. A Flood Warning 
has been issued to cover this hazard. Please continue to heed any 
remaining road closures.

LAT...LON 3865 7570 3865 7541 3847 7541 3849 7569

$$

JRK

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 9, 12:51 PM EDTSpecial Weather StatementPHISussex24 min
Jun 9, 1:04 PM EDTSpecial Weather StatementPHIKent56 min
Jun 9, 1:21 PM EDTSevere Thunderstorm WarningPHIKent39 min
Jun 9, 1:25 PM EDTFlash Flood WarningPHISussex4 hr
Jun 9, 1:35 PM EDTAreal Flood AdvisoryPHIKent71 min
Jun 9, 1:35 PM EDTSpecial Weather StatementPHISussex25 min
Jun 9, 2:00 PM EDTSpecial Weather StatementPHISussex30 min
Jun 9, 2:24 PM EDTSevere Thunderstorm WarningPHIKent, Sussex51 min
Jun 9, 2:42 PM EDTAreal Flood AdvisoryPHIKent, Sussex58 min
Jun 9, 2:48 PM EDTSevere Thunderstorm WarningPHISussex42 min
Jun 9, 3:06 PM EDTSpecial Weather StatementPHINew Castle24 min
Jun 9, 3:26 PM EDTSpecial Weather StatementPHISussex34 min
Jun 9, 3:45 PM EDTSpecial Weather StatementPHIKent45 min
Jun 9, 3:47 PM EDTAreal Flood AdvisoryPHIKent, New Castle3 hr
Jun 9, 3:53 PM EDTSevere Thunderstorm WarningPHIKent, New Castle37 min
Jun 9, 4:06 PM EDTSpecial Weather StatementPHISussex39 min
Jun 9, 4:15 PM EDTFlash Flood WarningPHISussex3 hr
Jun 9, 4:20 PM EDTFlash Flood WarningPHIKent3 hr
Jun 9, 4:24 PM EDTSpecial Weather StatementPHIKent51 min
Jun 9, 5:31 PM EDTSpecial Weather StatementPHISussex44 min
Jun 9, 5:44 PM EDTAreal Flood WarningPHISussex4 hr
Jun 9, 6:44 PM EDTAreal Flood WarningPHISussex3 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.