Alert archive / Delaware / Flash Flood Warnings in 2017

Flash Flood Warning 4, NWS Philadelphia/Mount Holly

June 19, 2017Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 19, 2017, 8:20 PM EDT for Sussex County, Delaware. It was in force for 3 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
Jun 19, 2017, 8:20 PM EDT (00:20 UTC)
Expired
Jun 19, 2017, 11:15 PM EDT
In force
3 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), 38 km from the middle of the area, began a volume at 00:24 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.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 00:00Z, 0.3 hours before the alert went out and 68 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 2017-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1394 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 2017-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 162 square meters per square second.193958Sfc1 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
1394 J/kg
Mixed-layer CIN
-55 J/kg
Mixed-layer LCL
1009 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
162 m²/s²
0-3 km storm-relative helicity
157 m²/s²
Significant tornado parameter
1.2
Supercell composite
8.5

Open this sounding in Storm Lab

The text

As transmitted.

464 
WGUS51 KPHI 200020
FFWPHI
DEC005-200315-
/O.NEW.KPHI.FF.W.0004.170620T0020Z-170620T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
820 PM EDT MON JUN 19 2017

The National Weather Service in Mount Holly NJ has issued a

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

* Until 1115 PM EDT

* At 818 PM EDT#...Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Two inches of rain have already 
  fallen in the warned area. Additional training of thunderstorms 
  may result in another inch of rainfall. The additional rainfall 
  will likely lead to Flash flooding.


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.

&&

LAT...LON 3846 7547 3869 7547 3870 7505 3845 7504
      3846 7505 3845 7505

$$

MWG
1 follow-up statement
635 
WGUS71 KPHI 200303
FFSPHI

Flash Flood Statement
National Weather Service MOUNT HOLLY NJ
1103 PM EDT MON JUN 19 2017

DEC005-200311-
/O.CAN.KPHI.FF.W.0004.000000T0000Z-170620T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-
1103 PM EDT MON JUN 19 2017

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN SUSSEX COUNTY IS
CANCELLED...

The heavy rain has ended. Light rain will continue for a couple more 
hours but flooding is no longer expected to pose a threat. 

LAT...LON 3846 7547 3869 7547 3870 7505 3845 7504
      3846 7505 3845 7505

$$

amc

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 19, 8:12 PM EDTSpecial Weather StatementPHISussex48 min
Jun 19, 8:24 PM EDTSevere Thunderstorm WarningPHIKent, Sussex36 min
Jun 19, 8:32 PM EDTAreal Flood AdvisoryPHIKent, Sussex3 hr
Jun 19, 8:45 PM EDTSpecial Weather StatementPHISussex30 min

Nearby

Flash Flood Warnings in Delaware, 2017Every flash flood warning in 2017

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; radar from the NEXRAD Level II archive.