Alert archive / Delaware / Flash Flood Warnings in 2018

Flash Flood Warning 87, NWS Philadelphia/Mount Holly

August 31, 2018New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 31, 2018, 5:00 PM EDT for New Castle County, Delaware. It was in force for 4 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, 5:00 PM EDT (21:00 UTC)
Expired
Aug 31, 2018, 9:00 PM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

County New Castle County, DE

What was reported inside it

TimeReportWhereRemark
Aug 31, 7:00 PM EDTFLASH FLOODMiddletown, DENUMEROUS FLOODED ROADWAYS AND INTERSECTIONS THROUGHOUT TOWN. SEVERAL VEHICLES HAVE STALLED DUE TO THE WATER, BUT NO WATER RESCUES HAVE OCCURRED.
Aug 31, 7:19 PM EDTHEAVY RAIN 6.161 Sse Middletown, DEOVER 5 INCHES OF RAIN FELL BETWEEN 5 AND 7 PM.

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

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.0 hours before the alert went out and 158 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, Washington/Dulle, VA at 12:00Z on 2018-08-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 425 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, Washington/Dulle, VA at 12:00Z on 2018-08-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 20 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
425 J/kg
Mixed-layer CIN
-35 J/kg
Mixed-layer LCL
930 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
68 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

132 
WGUS51 KPHI 312100
FFWPHI
DEC003-010100-
/O.NEW.KPHI.FF.W.0087.180831T2100Z-180901T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Southwestern New Castle County in northern Delaware...

* Until 900 PM EDT.

* At 459 PM EDT, Doppler radar indicated heavy rain across the 
  warned area. Up to 2 to 3 inches of rain have already fallen. 
  Additional rainfall is moving across the area which is expected to 
  lead to additional Flash flooding.

* Some locations that could experience flooding include...
  Middletown, Mount Pleasant, Townsend and Odessa. 

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 3958 7570 3935 7558 3936 7577 3957 7578

$$

Robertson
3 follow-up statements
672 
WGUS71 KPHI 312227
FFSPHI

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

DEC003-010100-
/O.CON.KPHI.FF.W.0087.000000T0000Z-180901T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-
627 PM EDT FRI AUG 31 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 900 PM EDT FOR
SOUTHWESTERN NEW CASTLE COUNTY...

At 622 PM EDT, emergency management reported flooding in and around 
Milton due to an estimated 6 to 8 inches of rainfall. Flash flooding 
is already occurring and heavy rain continues to fall which will 
continue to lead to flash flooding.

Some locations that could experience flooding include...
Middletown, Mount Pleasant, Townsend and Odessa. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3958 7570 3935 7558 3936 7577 3957 7578

$$

Robertson
525 
WGUS71 KPHI 312251
FFSPHI

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

DEC003-010100-
/O.CON.KPHI.FF.W.0087.000000T0000Z-180901T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-
651 PM EDT FRI AUG 31 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 900 PM EDT FOR
SOUTHWESTERN NEW CASTLE COUNTY...

At 650 PM EDT, emergency management reported flooding in and around 
Middletown due to an estimated 6 to 8 inches of rainfall. Flash 
flooding is already occurring and heavy rain continues to fall which 
will continue to lead to flash flooding.

Some locations that could experience flooding include...
Middletown, Mount Pleasant, Townsend and Odessa. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3958 7570 3935 7558 3936 7577 3957 7578

$$

Robertson
769 
WGUS71 KPHI 010052
FFSPHI

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

DEC003-010101-
/O.EXP.KPHI.FF.W.0087.000000T0000Z-180901T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-
852 PM EDT FRI AUG 31 2018

...THE FLASH FLOOD WARNING FOR SOUTHWESTERN NEW CASTLE COUNTY WILL
EXPIRE AT 900 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 a portion of the area for any residual 
flooding. There will continue to be light to moderate rain through 
this evening as well which many exacerbate any flooding. Please 
continue to heed any remaining road closures.

LAT...LON 3958 7570 3935 7558 3936 7577 3957 7578

$$

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, 12:15 PM EDTFlash Flood WarningPHIKent, Sussex7 hr
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, 5:14 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.