Alert archive / Maryland / Flash Flood Warnings in 2018

Flash Flood Warning 67, NWS Philadelphia/Mount Holly

August 11, 2018Kent County, New Castle County, Delaware; Cecil County, Kent County, Queen Anne's County, Maryland; Salem County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 11, 2018, 6:12 PM EDT for Kent County, New Castle County, Delaware; Cecil County, Kent County, Queen Anne's County, Maryland; Salem County, New Jersey. 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: Aug 11, 2018, 6:12 PM EDT (22:12 UTC)
Expired: Aug 11, 2018, 9:15 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Kent County, DE, New Castle County, DE, Cecil County, MD, Kent County, MD, Queen Anne's County, MD, Salem County, NJ

The radar

The Dover AFB radar (KDOX), 66 km from the middle of the area, began a volume at 22:12 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.2 hours before the alert went out and 159 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 963 J/kg
Mixed-layer CIN: -38 J/kg
Mixed-layer LCL: 1021 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 59 m²/s²
0-3 km storm-relative helicity: 57 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.6

Open this sounding in Storm Lab

The text

As transmitted.

007 
WGUS51 KPHI 112212
FFWPHI
DEC001-003-MDC015-029-035-NJC033-120115-
/O.NEW.KPHI.FF.W.0067.180811T2212Z-180812T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
612 PM EDT SAT AUG 11 2018

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Southwestern New Castle County in northern Delaware...
  Northwestern Kent County in central Delaware...
  Northeastern Queen Anne's County in northeastern Maryland...
  Kent County in northeastern Maryland...
  Southeastern Cecil County in northeastern Maryland...
  Salem County in southern New Jersey...

* Until 915 PM EDT.

* At 609 PM EDT, Doppler radar indicated a large area of 
  thunderstorms extending from the Chesapeake Bay eastward across 
  northern Delaware into extreme southwest New Jersey. Rainfall 
  rates of between one and two inches per hour are possible with 
  these thunderstorms...resulting in flash flooding in the heavier 
  rain bands.

* Some locations that could experience flooding include...
  Vineland, Millville, Middletown, Elkton, Pennsville, Smyrna,
  Chestertown, Salem, Woodstown, Alloway, Clayton, Quinton, Delaware
  City, Elmer, Rock Hall, Charlestown, Church Hill, Cecilton,
  Millington and Sudlersville.

LAT...LON 3931 7618 3942 7600 3955 7602 3955 7607
      3956 7607 3969 7536 3957 7506 3937 7503
      3956 7524 3945 7542 3934 7536 3939 7521
      3930 7531 3939 7548 3929 7539 3928 7538
      3906 7623 3917 7628

$$

jjm

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 11, 3:24 AM EDT	Flash Flood Watch	PHI	Kent, New Castle	20 hr
Aug 11, 4:26 AM EDT	Coastal Flood Advisory	PHI	Kent, New Castle, Sussex	24 hr
Aug 11, 1:23 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	37 min
Aug 11, 4:19 PM EDT	Areal Flood Advisory	PHI	New Castle	3 hr
Aug 11, 4:19 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	29 min
Aug 11, 5:20 PM EDT	Areal Flood Advisory	PHI	Kent, New Castle	4 hr
Aug 11, 6:08 PM EDT	Severe Thunderstorm Warning	PHI	Kent, New Castle	52 min
Aug 11, 6:45 PM EDT	Flash Flood Warning	PHI	Kent	5 hr
Aug 11, 6:55 PM EDT	Severe Thunderstorm Warning	PHI	Kent	50 min
Aug 11, 7:42 PM EDT	Special Weather Statement	PHI	Kent	48 min
Aug 11, 5:24 PM EDT	Special Weather Statement	PHI	Cecil	36 min
Aug 11, 5:27 AM EDT	Areal Flood Advisory	PHI	Hunterdon, Morris, Warren	4 hr
Aug 11, 6:06 AM EDT	Areal Flood Advisory	PHI	Hunterdon, Warren	6 hr
Aug 11, 6:31 AM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset	7 hr
Aug 11, 7:16 AM EDT	Flash Flood Warning	PHI	Middlesex, Somerset	4 hr
Aug 11, 10:49 AM EDT	Areal Flood Advisory	PHI	Middlesex, Somerset	3 hr
Aug 11, 11:29 AM EDT	Areal Flood Advisory	PHI	Atlantic	4 hr
Aug 11, 11:46 AM EDT	Special Marine Warning	PHI		119 min
Aug 11, 11:55 AM EDT	Special Weather Statement	PHI	Burlington	35 min
Aug 11, 12:27 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester, Ocean	4 hr
Aug 11, 12:39 PM EDT	Special Weather Statement	PHI	Ocean	36 min
Aug 11, 12:55 PM EDT	Special Marine Warning	PHI		65 min
Aug 11, 1:07 PM EDT	Flash Flood Warning	PHI	Atlantic, Cape May	4 hr
Aug 11, 1:26 PM EDT	Special Marine Warning	PHI		2 hr
Aug 11, 1:42 PM EDT	Special Marine Warning	PHI		2 hr
Aug 11, 1:51 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden	39 min
Aug 11, 2:00 PM EDT	Flash Flood Warning	PHI	Warren	9 hr
Aug 11, 2:05 PM EDT	Special Weather Statement	PHI	Cape May	25 min
Aug 11, 2:06 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester	3 hr
Aug 11, 2:19 PM EDT	Special Marine Warning	PHI		86 min
Aug 11, 2:20 PM EDT	Areal Flood Advisory	PHI	Cape May, Cumberland	3 hr
Aug 11, 2:30 PM EDT	Flash Flood Warning	PHI	Hunterdon, Morris, Warren	3 hr
Aug 11, 2:46 PM EDT	Flash Flood Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset	3 hr
Aug 11, 2:58 PM EDT	Special Weather Statement	PHI	Cumberland	47 min
Aug 11, 3:06 PM EDT	Flash Flood Warning	PHI	Warren	4 hr
Aug 11, 3:13 PM EDT	Special Weather Statement	PHI	Hunterdon	47 min
Aug 11, 3:23 PM EDT	Areal Flood Advisory	PHI	Morris, Sussex	3 hr
Aug 11, 3:24 PM EDT	Special Weather Statement	PHI	Atlantic, Cumberland	51 min
Aug 11, 3:32 PM EDT	Flash Flood Warning	PHI	Atlantic	3 hr
Aug 11, 3:47 PM EDT	Flash Flood Warning	PHI	Morris	3 hr
Aug 11, 4:11 PM EDT	Special Marine Warning	PHI		2 hr
Aug 11, 4:28 PM EDT	Special Marine Warning	PHI		2 hr
Aug 11, 5:00 PM EDT	Areal Flood Advisory	PHI	Gloucester, Salem	3 hr
Aug 11, 5:26 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Morris, Warren	4 hr
Aug 11, 5:36 PM EDT	Areal Flood Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset	4 hr
Aug 11, 6:11 PM EDT	Special Marine Warning	PHI		2 hr
Aug 11, 7:35 PM EDT	Areal Flood Advisory	PHI	Atlantic, Cumberland	3 hr
Aug 11, 7:46 PM EDT	River Flood Warning	PHI	Essex, Morris, Passaic	4 days

Nearby

Flash Flood Warnings in Maryland, 2018 Flash Flood Warnings in Delaware, 2018 Flash Flood Warnings in New Jersey, 2018 Every 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; radar from the NEXRAD Level II archive.