Alert archive / Maryland / Flash Flood Warnings in 2018

Flash Flood Warning 108, NWS Philadelphia/Mount Holly

October 11, 2018Caroline County, Talbot County, Maryland; Kent County, Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Oct 11, 2018, 11:47 PM EDT for Caroline County, Talbot County, Maryland; Kent County, Sussex 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
Oct 11, 2018, 11:47 PM EDT (03:47 UTC)
Expired
Oct 12, 2018, 3:31 AM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

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

The radar

The Dover AFB radar (KDOX), 21 km from the middle of the area, began a volume at 03:49 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
Oct 12, 2:04 AM EDTFLOODRehoboth Beach, DERT 1 HAS STANDING WATER ON ROADWAY FROM REHOBOTH BEACH TO FENWICK ISLAND.
Oct 12, 2:30 AM EDTFLOOD2 N Millsboro, DEDOC FRAME ROAD CLOSED FROM FLOODING. TIME ESTIMATED.

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 00:00Z, 3.8 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 00:00Z on 2018-10-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 959 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 2018-10-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 212 square meters per square second.19395878Sfc1 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
959 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
634 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
212 m²/s²
0-3 km storm-relative helicity
200 m²/s²
Significant tornado parameter
1.1
Supercell composite
4.3

Open this sounding in Storm Lab

The text

As transmitted.

154 
WGUS51 KPHI 120347
FFWPHI
DEC001-005-MDC011-041-120745-
/O.NEW.KPHI.FF.W.0108.181012T0347Z-181012T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1147 PM EDT THU OCT 11 2018

The National Weather Service in Mount Holly NJ has issued a

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

* Until 345 AM EDT.

* At 1143 PM EDT, Doppler radar indicated heavy rain across portions 
  of the warned area. Up to two inches of rain have already fallen. 
  Additional rainfall amounts of two inches are possible. This 
  amount of rainfall is capable of producing flash flooding. 
  
* Some locations that could experience flooding include...
  Georgetown, Milford, Seaford, Millsboro, Laurel, Harrington, Lewes,
  Federalsburg, Milton, Selbyville, Bridgeville, Delmar, Trappe,
  Dagsboro, Preston, Millville, Ellendale, Bowers, Henlopen Acres and
  Smithville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3846 7569 3864 7571 3869 7577 3868 7580
      3870 7580 3871 7584 3868 7593 3864 7597
      3864 7615 3865 7615 3908 7537 3905 7537
      3892 7528 3881 7514 3881 7506 3846 7504
      3845 7539

$$

Kruzdlo
1 follow-up statement
048 
WGUS71 KPHI 120731
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
331 AM EDT FRI OCT 12 2018

DEC001-005-MDC011-041-120739-
/O.CAN.KPHI.FF.W.0108.000000T0000Z-181012T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex DE-Kent DE-Talbot MD-Caroline MD-
331 AM EDT FRI OCT 12 2018

...THE FLASH FLOOD WARNING FOR SUSSEX...SOUTHERN KENT...SOUTHEASTERN
TALBOT AND SOUTHERN CAROLINE COUNTIES IS CANCELLED...

This flash flood warning has been converted to a flood warning. 
Three to five inches of rain fell since last evening. It will take 
some time to drain.

LAT...LON 3846 7569 3864 7571 3869 7577 3868 7580
      3870 7580 3871 7584 3868 7593 3864 7597
      3864 7615 3865 7615 3908 7537 3905 7537
      3892 7528 3881 7514 3881 7506 3846 7504
      3845 7539

$$

Kruzdlo

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 11, 8:27 PM EDTAreal Flood AdvisoryPHICecil, Kent, Queen Anne's8 hr
Oct 11, 10:06 PM EDTFlash Flood WarningPHICaroline, Kent, Queen Anne's, Talbot6 hr
Oct 11, 11:36 PM EDTFlash Flood WarningPHIKent, Queen Anne's4 hr
Oct 12, 12:08 AM EDTFlash Flood WarningPHIKent, Queen Anne's4 hr
Oct 12, 3:28 AM EDTAreal Flood WarningPHICaroline, Talbot6 hr
Oct 12, 3:36 AM EDTAreal Flood WarningPHICaroline, Kent, Queen Anne's, Talbot6 hr
Oct 12, 3:46 AM EDTAreal Flood WarningPHIKent, Queen Anne's7 hr
Oct 11, 11:54 PM EDTHigh Wind WarningPHISussex9 hr
Oct 12, 11:42 AM EDTCoastal Flood AdvisoryPHISussex4 hr
Oct 12, 2:46 PM EDTAreal Flood WarningPHIKent7 hr

Nearby

Flash Flood Warnings in Maryland, 2018Flash 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.