Alert archive / Delaware / Flash Flood Warnings in 2018

Flash Flood Warning 96, NWS Philadelphia/Mount Holly

September 8, 2018Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 8, 2018, 12:11 AM EDT for Sussex County, Delaware. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 8, 2018, 12:11 AM EDT (04:11 UTC)
Expired
Sep 8, 2018, 4:15 AM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

County Sussex County, DE

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 00:00Z, 4.2 hours before the alert went out and 69 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 00:00Z on 2018-09-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1567 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 00:00Z on 2018-09-08The 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
1567 J/kg
Mixed-layer CIN
-21 J/kg
Mixed-layer LCL
957 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
20 m²/s²
0-3 km storm-relative helicity
33 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

864 
WGUS51 KPHI 080411
FFWPHI
DEC005-080815-
/O.NEW.KPHI.FF.W.0096.180908T0411Z-180908T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1211 AM EDT SAT SEP 8 2018

The National Weather Service in Mount Holly NJ has issued a

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

* Until 415 AM EDT.

* At 1211 AM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between one and two inches of 
  rain have already fallen. Flash flooding is expected to begin 
  shortly in the areas of heaviest rain.

* Some locations that could experience flooding include...
  Millsboro, Selbyville, Dagsboro, Millville, Long Neck, Ocean View,
  Frankford and South Bethany.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

Please report flooding to your local law enforcement agency when you
can do so safely.

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 3862 7536 3865 7504 3845 7504 3846 7505
      3845 7505 3845 7535

$$

MPS
2 follow-up statements
042 
WGUS71 KPHI 080721
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
321 AM EDT SAT SEP 8 2018

DEC005-080815-
/O.CON.KPHI.FF.W.0096.000000T0000Z-180908T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-
321 AM EDT SAT SEP 8 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 AM EDT FOR
SOUTHEASTERN SUSSEX COUNTY...

At 320 AM EDT, Doppler radar indicated that the heavy rain that fell 
earlier has ended, but flash flooding is occurring and will continue 
through the early morning hours.

Some locations that could experience flooding include...
Millsboro, Selbyville, Dagsboro, Millville, Long Neck, Ocean View,
Frankford and South Bethany.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, country roads, farmland, and other low lying
spots.

Please report flooding to your local law enforcement agency when you
can do so safely.

&&

LAT...LON 3862 7536 3865 7504 3845 7504 3846 7505
      3845 7505 3845 7535

$$

MPS
980 
WGUS71 KPHI 080806
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
406 AM EDT SAT SEP 8 2018

DEC005-080815-
/O.EXP.KPHI.FF.W.0096.000000T0000Z-180908T0815Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-
406 AM EDT SAT SEP 8 2018

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN SUSSEX COUNTY WILL EXPIRE
AT 415 AM EDT...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed any remaining road closures. 
Additional rainfall through this morning may result in more flooding 
across this area.

LAT...LON 3862 7536 3865 7504 3845 7504 3846 7505
      3845 7505 3845 7535

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 7, 8:32 PM EDTFlash Flood WarningPHINew Castle2 hr
Sep 7, 11:19 PM EDTRip Current StatementPHISussex9 days
Sep 7, 11:20 PM EDTAreal Flood WarningPHINew Castle4 hr
Sep 7, 11:40 PM EDTSpecial Weather StatementPHISussex35 min
Sep 8, 3:34 AM EDTFlood WatchPHINew Castle60 hr
Sep 8, 5:31 AM EDTCoastal Flood WatchPHIKent11 hr
Sep 8, 5:31 AM EDTCoastal Flood AdvisoryPHINew Castle, Sussex21 hr
Sep 8, 8:15 AM EDTAreal Flood AdvisoryPHINew Castle119 min
Sep 8, 11:54 AM EDTSpecial Weather StatementPHISussex21 min
Sep 8, 4:49 PM EDTCoastal Flood WatchPHIKent, New Castle, Sussex7 hr
Sep 8, 4:49 PM EDTCoastal Flood WarningPHIKent, Sussex6 hr
Sep 8, 4:49 PM EDTHigh Surf AdvisoryPHISussex60 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; the sounding from the Mesonet's radiosonde archive.