Alert archive / Delaware / Flash Flood Warnings in 2020

Flash Flood Warning 58, NWS Philadelphia/Mount Holly

August 12, 2020Caroline County, Maryland; Kent County, Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 12, 2020, 3:46 PM EDT for Caroline County, Maryland; Kent County, Sussex County, Delaware. It was in force for 3 hr. 3 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 12, 2020, 3:46 PM EDT (19:46 UTC)
Expired
Aug 12, 2020, 6:45 PM EDT
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Kent County, DE, Sussex County, DE, Caroline County, MD

The radar

The Dover AFB radar (KDOX), 15 km from the middle of the area, began a volume at 19:47 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 12, 4:00 PM EDTFLASH FLOODHarrington, DEWATER RESCUE NEAR THE INTERSECTION OF LIBERTY STREET AND HOWARD DILL AVENUE. TIME BASED ON DISPATCH REPORT.
Aug 12, 4:00 PM EDTHEAVY RAIN 2.121 E Harrington, DE2.12 INCHES OF RAIN WITHIN AN HOUR AT THE HARRINGTON DEOS STATION.
Aug 12, 4:10 PM EDTHEAVY RAIN 3.061 Ese Frederica, DE3.06 INCHES OF RAIN WITHIN AN HOUR AT THE FREDERICA DEOS STATION.

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, 7.8 hours before the alert went out and 99 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 2020-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1590 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 2020-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 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
1590 J/kg
Mixed-layer CIN
-21 J/kg
Mixed-layer LCL
729 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
3 m²/s²
0-3 km storm-relative helicity
17 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

749 
WGUS51 KPHI 121946
FFWPHI
DEC001-005-MDC011-122245-
/O.NEW.KPHI.FF.W.0058.200812T1946Z-200812T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
346 PM EDT Wed Aug 12 2020

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Northwestern Sussex County in southern Delaware...
  Southern Kent County in central Delaware...
  Southeastern Caroline County in eastern Maryland...

* Until 645 PM EDT.

* At 345 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Over 2 inches of rain has 
  fallen so far. Flash flooding is expected.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  IMPACT...Flooding of small creeks and streams, urban areas, 
           highways, streets and underpasses as well as other 
           drainage and low lying areas.

* Some locations that could experience flooding include...
  Milford, Harrington, Milton, Bridgeville, Ellendale, Smithville,
  Agner, Andrewsville, Felton, Greenwood, Frederica, Houston and
  Farmington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

&&

LAT...LON 3871 7587 3901 7575 3900 7534 3874 7522
      3867 7563

FLASH FLOOD...RADAR INDICATED

$$

JJM

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 12:43 PM EDTAreal Flood AdvisoryPHICecil3 hr
Aug 12, 12:55 PM EDTAreal Flood AdvisoryPHICecil, Kent3 hr
Aug 12, 3:06 PM EDTAreal Flood AdvisoryPHICaroline, Queen Anne's3 hr
Aug 12, 3:20 PM EDTSevere Thunderstorm WarningPHICecil29 min
Aug 12, 3:36 PM EDTFlash Flood WarningPHICecil108 min
Aug 12, 4:02 PM EDTSpecial Weather StatementPHICaroline28 min
Aug 12, 4:11 PM EDTAreal Flood WarningPHICaroline, Talbot3 hr
Aug 12, 4:43 PM EDTAreal Flood AdvisoryPHICecil, Kent54 min
Aug 12, 12:55 PM EDTSpecial Weather StatementPHIKent35 min
Aug 12, 1:06 PM EDTFlash Flood WarningPHIKent, New Castle3 hr
Aug 12, 1:37 PM EDTAreal Flood AdvisoryPHINew Castle3 hr
Aug 12, 1:54 PM EDTSevere Thunderstorm WarningPHINew Castle51 min
Aug 12, 2:38 PM EDTSevere Thunderstorm WarningPHIKent52 min
Aug 12, 2:40 PM EDTFlash Flood WarningPHINew Castle3 hr
Aug 12, 3:15 PM EDTSevere Thunderstorm WarningPHIKent, Sussex45 min
Aug 12, 3:31 PM EDTFlash Flood WarningPHIKent3 hr
Aug 12, 4:00 PM EDTSpecial Weather StatementPHIKent30 min

Nearby

Flash Flood Warnings in Delaware, 2020Flash Flood Warnings in Maryland, 2020Every flash flood warning in 2020

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.