Alert archive / Pennsylvania / Flash Flood Warnings in 2019

Flash Flood Warning 25, NWS Philadelphia/Mount Holly

June 19, 2019Chester County, Delaware County, Pennsylvania; New Castle County, Delaware; Cecil County, Maryland

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 19, 2019, 11:11 PM EDT for Chester County, Delaware County, Pennsylvania; New Castle County, Delaware; Cecil County, Maryland. It was in force for 6 hr. 5 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: Jun 19, 2019, 11:11 PM EDT (03:11 UTC)
Expired: Jun 20, 2019, 5:15 AM EDT
In force: 6 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

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

The radar

The Philadelphia radar (KDIX), 111 km from the middle of the area, began a volume at 03:13 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

Time	Report	Where	Remark
Jun 20, 12:30 AM EDT	FLASH FLOOD	Garfield Park, DE	DE ROUTE 9 SOUTHBOUND NEAR MEMORIAL DRIVE IS CLOSED DUE TO FLOODING.
Jun 20, 1:20 AM EDT	FLOOD	1 Sw Hayden Park, DE	AIRPORT ROAD CLOSED AT NONESUCH CREEK.
Jun 20, 2:30 AM EDT	FLASH FLOOD	1 Ne Chester Springs, PA	FLASH FLOODING CLOSED CLOVER MILL ROAD NEAR PIKE SPRINGS ROAD. TIME ESTIMATED FROM RADAR AND NEARBY REPORTS.
Jun 20, 2:58 AM EDT	FLASH FLOOD	Lansdowne, PA	WATER RESCUE OF A STRANDED DRIVER.
Jun 20, 4:35 AM EDT	FLASH FLOOD	Chesterbrook, PA	THE RIVER GAUGE ON VALLEY CREEK NEAR VALLEY FORGE REACHED FLOOD STAGE.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 3.2 hours before the alert went out and 175 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: 1341 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 1152 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 30 m²/s²
0-3 km storm-relative helicity: 76 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.2

Open this sounding in Storm Lab

The text

As transmitted.

673 
WGUS51 KPHI 200311
FFWPHI
DEC003-MDC015-PAC029-045-200915-
/O.NEW.KPHI.FF.W.0025.190620T0311Z-190620T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1111 PM EDT Wed Jun 19 2019

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Northern New Castle County in northern Delaware...
  Northern Cecil County in northeastern Maryland...
  Chester County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 515 AM EDT Thursday.

* At 1110 PM EDT, Doppler radar indicated showers and thunderstorms 
  producing heavy rain across the warned area. Up to one inch of 
  rain has already fallen. Flash flooding is expected to begin 
  shortly in the areas of heaviest rain.

* Some locations that could experience flooding include...
  Wilmington, Newark, West Chester, Elkton, Calvert, Chester, 
  Phoenixville, Coatesville, Yeadon, Westtown, Downingtown, 
  Folcroft, Swarthmore, Elsmere, Kennett Square, New Castle, Oxford, 
  Parkesburg and North East.

Additional rainfall amounts of 2 to 3 inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other poor drainage areas and low lying spots.

&&

LAT...LON 3972 7623 3973 7610 3976 7606 3987 7599
      4011 7594 4024 7568 4024 7560 4009 7546
      4002 7531 3994 7524 3987 7526 3977 7546
      3972 7548 3972 7552 3965 7559 3961 7556
      3963 7561 3959 7561 3958 7559 3955 7608

$$

Iovino

1 follow-up statement

494 
WGUS71 KPHI 200457
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1257 AM EDT Thu Jun 20 2019

MDC015-200506-
/O.CAN.KPHI.FF.W.0025.000000T0000Z-190620T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cecil MD-
1257 AM EDT Thu Jun 20 2019

...THE FLASH FLOOD WARNING FOR NORTHERN CECIL COUNTY IS CANCELLED...

Flooding is no longer expected to pose a threat. Please continue to
heed any remaining road closures.

LAT...LON 3976 7606 3987 7599 4011 7594 4024 7568
      4024 7560 4009 7546 4002 7531 3994 7524
      3987 7526 3977 7546 3972 7548 3972 7552
      3965 7559 3961 7556 3963 7561 3959 7561
      3958 7559 3957 7578 3972 7579 3972 7613

$$

DEC003-PAC029-045-200915-
/O.CON.KPHI.FF.W.0025.000000T0000Z-190620T0915Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Chester PA-Delaware PA-
1257 AM EDT Thu Jun 20 2019

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 515 AM EDT FOR
NORTHERN NEW CASTLE...CHESTER AND DELAWARE COUNTIES...

At 1256 AM EDT, Doppler radar indicated showers and thunderstorms 
producing heavy rain across the warned area. Up to an inch or two of 
rain has already fallen. Flash flooding is expected.

Some locations that could experience flooding include...
Wilmington, Newark, West Chester, Chester, Phoenixville, 
Coatesville, Yeadon, Westtown, Downingtown, Folcroft, Swarthmore, 
Elsmere, Kennett Square, New Castle, Oxford, Parkesburg, West Grove, 
East Lansdowne and Honey Brook.

Additional rainfall amounts in excess of an inch are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other poor drainage areas and low lying spots.

&&

LAT...LON 3976 7606 3987 7599 4011 7594 4024 7568
      4024 7560 4009 7546 4002 7531 3994 7524
      3987 7526 3977 7546 3972 7548 3972 7552
      3965 7559 3961 7556 3963 7561 3959 7561
      3958 7559 3957 7578 3972 7579 3972 7613

$$

Iovino

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 19, 9:09 PM EDT	Areal Flood Warning	PHI	Philadelphia	3 hr
Jun 19, 9:50 PM EDT	Special Weather Statement	PHI	Lebanon	55 min
Jun 19, 10:47 PM EDT	Areal Flood Advisory	PHI	Berks	50 min
Jun 19, 11:34 PM EDT	Flash Flood Warning	PHI	Berks	6 hr
Jun 20, 12:39 AM EDT	Areal Flood Advisory	PHI	Montgomery	7 min
Jun 20, 12:45 AM EDT	Flash Flood Warning	PHI	Montgomery, Philadelphia	6 hr
Jun 20, 3:40 AM EDT	River Flood Warning	PHI	Delaware	111 min
Jun 20, 3:59 AM EDT	River Flood Warning	PHI	Chester	7 hr
Jun 20, 5:10 AM EDT	Areal Flood Warning	PHI	Chester, Delaware	12 hr
Jun 20, 5:19 AM EDT	River Flood Warning	PHI	Chester, Delaware	13 hr
Jun 20, 5:24 AM EDT	Areal Flood Warning	PHI	Berks	6 hr
Jun 20, 6:14 AM EDT	Areal Flood Warning	PHI	Montgomery, Philadelphia	10 hr
Jun 20, 6:31 AM EDT	River Flood Warning	PHI	Delaware	3 hr
Jun 20, 1:24 PM EDT	Special Weather Statement	PHI	Berks, Chester, Montgomery	51 min
Jun 20, 1:28 PM EDT	Areal Flood Advisory	PHI	Berks	4 hr
Jun 20, 2:13 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Chester, Delaware, Lehigh, Montgomery	4 hr
Jun 20, 2:26 PM EDT	Special Weather Statement	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	94 min
Jun 20, 2:33 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	57 min
Jun 20, 2:48 PM EDT	Flash Flood Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	4 hr
Jun 20, 3:20 PM EDT	Flash Flood Warning	PHI	Bucks	4 hr
Jun 20, 4:58 PM EDT	River Flood Warning	PHI	Chester	4 hr
Jun 20, 6:33 PM EDT	Areal Flood Warning	PHI	Montgomery	3 hr
Jun 19, 11:46 PM EDT	River Flood Warning	PHI	New Castle	104 min
Jun 20, 7:55 PM EDT	Areal Flood Advisory	PHI	Kent, Sussex	4 hr
Jun 20, 3:48 PM EDT	Special Weather Statement	PHI	Cecil	27 min

Nearby

Flash Flood Warnings in Pennsylvania, 2019 Flash Flood Warnings in Delaware, 2019 Flash Flood Warnings in Maryland, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.