Alert archive / Pennsylvania / Flash Flood Warnings in 2020

Flash Flood Warning 55, NWS Philadelphia/Mount Holly

August 12, 20204 counties in Pennsylvania; New Castle County, Delaware; Burlington County, Camden County, Gloucester County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 12, 2020, 2:40 PM EDT for 4 counties in Pennsylvania; New Castle County, Delaware; Burlington County, Camden County, Gloucester County, New Jersey. It was in force for 3 hr. 14 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, 2:40 PM EDT (18:40 UTC)
Expired: Aug 12, 2020, 5:36 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties New Castle County, DE, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 63 km from the middle of the area, began a volume at 18:43 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
Aug 12, 2:40 PM EDT	FLOOD	1 Se Center City, PA	FLOODING ON I-95 SOUTHBOUND BETWEEN EXIT: I-676/US 30 - CENTRAL PHILA/CALLOWHILL ST AND EXIT 20: COLUMBUS BLVD/WASHINGTON AVE.
Aug 12, 2:45 PM EDT	FLASH FLOOD	1 Sw Caln Twp, PA	CORRECTS PREVIOUS REPORT FROM 1 SW CALN TWP. WATER RESCUE ON LINCOLN HWY AT BAILEY RD.
Aug 12, 3:11 PM EDT	FLOOD	1 Nnw Eddystone, PA	FLOODING ON I-95 NORTHBOUND 0.5 MILES SOUTH OF EXIT 7: I-476 NORTH - PLYMOUTH MEETING.
Aug 12, 3:13 PM EDT	FLASH FLOOD	1 N Wenonah, NJ	PHOTO SHOWS ONE TO TWO FEET OF WATER RUSHING DOWN PRINCETON BLVD INTO THE OAK VALLEY PARK.
Aug 12, 3:14 PM EDT	FLOOD	Hainesport, NJ	FLOODING ON NJ 38 WESTBOUND AT CR 641/LUMBERTON-HAINSPORT RD (HAINESPORT TWP). JUGHANDLE CLOSED.
Aug 12, 3:22 PM EDT	FLOOD	1 Ene Eddystone, PA	FLOODING ON I-95 SOUTHBOUND AT EXIT 7: I-476 NORTH - PLYMOUTH MEETINGS.
Aug 12, 3:25 PM EDT	FLASH FLOOD	1 Wsw Tinicum Twp, PA	WATER RESCUE REPORTED ON INDUSTRIAL HIGHWAY.
Aug 12, 3:25 PM EDT	FLASH FLOOD	1 Wsw Woodbury Heights, NJ	CORRECTS PREVIOUS FLASH FLOOD REPORT FROM 1 WSW WOODBURY HEIGHTS. FLASH FLOODING ON THE NEW JERSEY TURNPIKE AT NJ-45. ABOUT 3 FEET OF WATER ON THE NORTHBOUND SIDE WITH 3 CARS AND A TRACTOR TRAILER STRANDED. ABOUT A FOOT OF WATER IN THE SOUTHBOUND LANE.
Aug 12, 3:25 PM EDT	FLASH FLOOD	1 Wsw Woodbury Heights, NJ	FLASH FLOODING ON NJ-45 NEAR THE NEW JERSEY TURNPIKE. ABOUT 3 FEET OF WATER ON THE NORTHBOUND SIDE WITH 3 CARS AND A TRACTOR TRAILER STRANDED. ABOUT A FOOT OF WATER IN THE SOUTHBOUND LANE.
Aug 12, 3:35 PM EDT	HEAVY RAIN 4.33	Deptford Twp, NJ	STORM TOTAL RAINFALL WITH SMALL STREAM FLOODING.
Aug 12, 3:45 PM EDT	FLASH FLOOD	1 Wsw Woodbury Heights, NJ	FLOODING ON THE NEW JERSEY TURNPIKE SOUTH OF EXIT 3. ALL LANES CLOSED. TIME BASED ON DISPATCH REPORT.
Aug 12, 3:50 PM EDT	FLASH FLOOD	1 E Wenonah, NJ	FLASH FLOODING CLOSED PORTIONS OF THE FOLLOWING ROADS IN AND NEAR MANTUA TWP: GLASSBORO RD, BRIDGETON PIKE NEAR BARRY DR, AND LIVINGSTON RD.
Aug 12, 4:30 PM EDT	HEAVY RAIN 4	2 Sse Chatsworth, NJ	ALL FELL WITHIN 90 MINUTES.
Aug 12, 4:53 PM EDT	FLASH FLOOD	Thorndale, PA	WATER RESCUE REPORTED ON PARK DR AT G O CARSON BLVD.

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, 6.7 hours before the alert went out and 208 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: 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.

169 
WGUS51 KPHI 121840
FFWPHI
DEC003-NJC005-007-015-PAC029-045-091-101-122245-
/O.NEW.KPHI.FF.W.0055.200812T1840Z-200812T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Northern New Castle County in northern Delaware...
  Camden County in southern New Jersey...
  Gloucester County in southern New Jersey...
  Burlington County in southern New Jersey...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Central Chester County in southeastern Pennsylvania...
  Southwestern Philadelphia County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 645 PM EDT.

* At 239 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Up to two inches of rain has 
  already fallen, and more is expected as a result of training 
  thunderstorms. 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.

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.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3966 7466 3969 7467 3973 7473 3967 7481
      3970 7535 3978 7541 3977 7546 3971 7550
      3973 7578 4002 7595 4004 7593 4004 7574
      3996 7449 3977 7439 3964 7439

FLASH FLOOD...RADAR INDICATED

$$

JJM

1 follow-up statement

600 
WGUS71 KPHI 122136
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
536 PM EDT Wed Aug 12 2020

DEC003-NJC005-007-015-PAC029-045-091-101-122144-
/O.CAN.KPHI.FF.W.0055.000000T0000Z-200812T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Camden NJ-Gloucester NJ-Burlington NJ-Montgomery PA-
Chester PA-Philadelphia PA-Delaware PA-
536 PM EDT Wed Aug 12 2020

...THE FLASH FLOOD WARNING FOR NORTHERN NEW CASTLE...CAMDEN...
GLOUCESTER...BURLINGTON...SOUTHEASTERN MONTGOMERY...CENTRAL
CHESTER...SOUTHWESTERN PHILADELPHIA AND DELAWARE COUNTIES IS
CANCELLED...

While light rain continues, the threat of additional flooding has 
ended now that the heavy rain has moved out of the area. The Flash 
Flood Warning has therefore been cancelled.  However, please 
continue to heed any remaining road closures.

LAT...LON 3966 7466 3969 7467 3973 7473 3967 7481
      3970 7535 3978 7541 3977 7546 3971 7550
      3973 7578 4002 7595 4004 7593 4004 7574
      3996 7449 3977 7439 3964 7439

$$

JJM

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 12, 11:48 AM EDT	Special Weather Statement	PHI	Philadelphia	27 min
Aug 12, 12:43 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	3 hr
Aug 12, 1:12 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	48 min
Aug 12, 1:47 PM EDT	Flash Flood Warning	PHI	Chester, Delaware	2 hr
Aug 12, 1:54 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	51 min
Aug 12, 2:04 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	21 min
Aug 12, 2:44 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	46 min
Aug 12, 3:20 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	29 min
Aug 12, 3:36 PM EDT	Flash Flood Warning	PHI	Chester	108 min
Aug 12, 5:04 PM EDT	Areal Flood Advisory	PHI	Lehigh, Northampton	56 min
Aug 12, 5:09 PM EDT	Areal Flood Warning	PHI	Berks	51 min
Aug 12, 12:55 PM EDT	Areal Flood Advisory	PHI	Kent, New Castle	3 hr
Aug 12, 12:55 PM EDT	Special Weather Statement	PHI	Kent	35 min
Aug 12, 1:06 PM EDT	Flash Flood Warning	PHI	Kent, New Castle	3 hr
Aug 12, 1:37 PM EDT	Areal Flood Advisory	PHI	New Castle	3 hr
Aug 12, 2:38 PM EDT	Severe Thunderstorm Warning	PHI	Kent	52 min
Aug 12, 3:06 PM EDT	Areal Flood Advisory	PHI	Kent, Sussex	3 hr
Aug 12, 3:15 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	45 min
Aug 12, 3:31 PM EDT	Flash Flood Warning	PHI	Kent	3 hr
Aug 12, 3:46 PM EDT	Flash Flood Warning	PHI	Kent, Sussex	3 hr
Aug 12, 4:00 PM EDT	Special Weather Statement	PHI	Kent	30 min
Aug 12, 12:06 PM EDT	Special Weather Statement	PHI	Monmouth	24 min
Aug 12, 12:16 PM EDT	Special Weather Statement	PHI	Burlington	29 min
Aug 12, 12:33 PM EDT	Severe Thunderstorm Warning	PHI	Burlington	42 min
Aug 12, 12:45 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	45 min
Aug 12, 1:12 PM EDT	Flash Flood Warning	PHI	Burlington	3 hr
Aug 12, 1:25 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	50 min
Aug 12, 1:57 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Ocean	48 min
Aug 12, 2:42 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Ocean	25 min
Aug 12, 3:12 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Gloucester, Salem	29 min
Aug 12, 3:54 PM EDT	Special Marine Warning	PHI		53 min

Nearby

Flash Flood Warnings in Pennsylvania, 2020 Flash Flood Warnings in New Jersey, 2020 Flash Flood Warnings in Delaware, 2020 Every 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.