Alert archive / Maryland / Flash Flood Warnings in 2019

Flash Flood Warning 47, NWS Philadelphia/Mount Holly

July 11, 2019Chester County, Pennsylvania; Cecil County, Kent County, Maryland; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 11, 2019, 5:12 PM EDT for Chester County, Pennsylvania; Cecil County, Kent County, Maryland; New Castle 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: Jul 11, 2019, 5:12 PM EDT (21:12 UTC)
Expired: Jul 11, 2019, 9:15 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties New Castle County, DE, Cecil County, MD, Kent County, MD, Chester County, PA

The radar

The Dover AFB radar (KDOX), 103 km from the middle of the area, began a volume at 21:14 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, 9.2 hours before the alert went out and 143 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: 114 J/kg
Mixed-layer CIN: -122 J/kg
Mixed-layer LCL: 1075 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 74 m²/s²
0-3 km storm-relative helicity: 102 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

459 
WGUS51 KPHI 112112
FFWPHI
DEC003-MDC015-029-PAC029-120115-
/O.NEW.KPHI.FF.W.0047.190711T2112Z-190712T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
512 PM EDT Thu Jul 11 2019

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Northwestern New Castle County in northern Delaware...
  Northeastern Kent County in northeastern Maryland...
  Cecil County in northeastern Maryland...
  Southwestern Chester County in southeastern Pennsylvania...

* Until 915 PM EDT.

* At 511 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across portions of the warned area. Flash flooding is 
  expected to begin shortly in the areas of heaviest rain.

* Some locations that could experience flooding include...
  Newark, Middletown, Elkton, Calvert, Kennett Square, Oxford, North
  East, West Grove, Rising Sun, Charlestown, Cecilton, Glen Roy,
  Blake, Glasgow, Bohemias Mills, West Nottingham, Mount Vernon, Bay
  View, Lombard and Richardsmere.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3972 7623 3973 7610 3976 7606 3983 7604
      3983 7602 3987 7599 3994 7598 3988 7563
      3937 7575 3936 7590 3938 7605 3943 7600
      3946 7601 3952 7598 3955 7603 3955 7608

$$

Kruzdlo

1 follow-up statement

238 
WGUS71 KPHI 120112
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
912 PM EDT Thu Jul 11 2019

DEC003-MDC015-029-PAC029-120121-
/O.EXP.KPHI.FF.W.0047.000000T0000Z-190712T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Kent MD-Cecil MD-Chester PA-
912 PM EDT Thu Jul 11 2019

...THE FLASH FLOOD WARNING FOR NORTHWESTERN NEW CASTLE...NORTHEASTERN
KENT...CECIL AND SOUTHWESTERN CHESTER COUNTIES WILL EXPIRE AT 915 PM
EDT...

The heavy rain is coming to an end. The flash flood warning will be 
allowed to expire. Please continue to heed any remaining road 
closures.

LAT...LON 3972 7623 3973 7610 3976 7606 3983 7604
      3983 7602 3987 7599 3994 7598 3988 7563
      3937 7575 3936 7590 3938 7605 3943 7600
      3946 7601 3952 7598 3955 7603 3955 7608

$$

Kruzdlo

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 11, 3:44 AM EDT	Flash Flood Watch	PHI	Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 2 more	18 hr
Jul 11, 12:33 PM EDT	Special Weather Statement	PHI	Chester	57 min
Jul 11, 1:23 PM EDT	Special Weather Statement	PHI	Chester, Delaware	52 min
Jul 11, 1:44 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Montgomery, Philadelphia	61 min
Jul 11, 2:41 PM EDT	Special Weather Statement	PHI	Philadelphia	64 min
Jul 11, 2:44 PM EDT	Special Weather Statement	PHI	Bucks, Montgomery	61 min
Jul 11, 2:50 PM EDT	Areal Flood Advisory Emergency	PHI	Berks, Chester, Montgomery	4 hr
Jul 11, 3:00 PM EDT	Flash Flood Warning	PHI	Berks, Chester, Montgomery	8 hr
Jul 11, 3:13 PM EDT	Areal Flood Advisory	PHI	Bucks, Carbon, Lehigh, Monroe, Northampton	4 hr
Jul 11, 3:33 PM EDT	Areal Flood Advisory	PHI	Northampton	4 hr
Jul 11, 3:45 PM EDT	Flash Flood Warning	PHI	Berks, Bucks, Lehigh, Montgomery, Northampton	4 hr
Jul 11, 4:45 PM EDT	Flash Flood Warning Emergency	PHI	Berks, Montgomery	4 hr
Jul 11, 5:20 PM EDT	Flash Flood Warning	PHI	Bucks, Chester, Montgomery	4 hr
Jul 11, 5:33 PM EDT	Areal Flood Advisory	PHI	Bucks	4 hr
Jul 11, 6:14 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Montgomery, Philadelphia	61 min
Jul 11, 6:15 PM EDT	Flash Flood Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	4 hr
Jul 11, 6:17 PM EDT	Areal Flood Advisory	PHI	Bucks	4 hr
Jul 11, 6:28 PM EDT	River Flood Warning	PHI	Montgomery	22 hr
Jul 11, 6:57 PM EDT	River Flood Warning	PHI	Montgomery	12 hr
Jul 11, 7:03 PM EDT	River Flood Warning	PHI	Chester, Montgomery, Philadelphia	26 hr
Jul 11, 7:19 PM EDT	River Flood Warning	PHI	Chester	7 hr
Jul 11, 7:47 PM EDT	Flash Flood Warning	PHI	Berks, Bucks, Lehigh, Montgomery	3 hr
Jul 11, 3:37 PM EDT	Special Weather Statement	PHI	Cecil	53 min
Jul 11, 4:55 PM EDT	Special Weather Statement	PHI	Cecil, Kent, Queen Anne's	65 min
Jul 11, 5:44 PM EDT	Severe Thunderstorm Warning	PHI	Caroline, Cecil, Kent, Queen Anne's, Talbot	61 min
Jul 11, 5:45 PM EDT	Areal Flood Advisory	PHI	Cecil, Kent, Queen Anne's, Talbot	4 hr
Jul 11, 6:39 PM EDT	Areal Flood Advisory	PHI	Caroline, Kent, Queen Anne's, Talbot	4 hr
Jul 11, 7:36 PM EDT	Special Weather Statement	PHI	Caroline	54 min

Nearby

Flash Flood Warnings in Maryland, 2019 Flash Flood Warnings in Pennsylvania, 2019 Flash Flood Warnings in Delaware, 2019 Every flash flood warning in 2019

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.