Alert archive / Pennsylvania / Flash Flood Warnings in 2018

Flash Flood Warning 1, NWS Philadelphia/Mount Holly

April 16, 2018Gloucester County, Salem County, New Jersey; 4 counties in Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Apr 16, 2018, 7:04 AM EDT for Gloucester County, Salem County, New Jersey; 4 counties in Pennsylvania; New Castle County, Delaware. It was in force for 4 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: Apr 16, 2018, 7:04 AM EDT (11:04 UTC)
Expired: Apr 16, 2018, 11:00 AM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

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

The radar

The Philadelphia radar (KDIX), 66 km from the middle of the area, began a volume at 11:06 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
Apr 16, 7:23 AM EDT	FLOOD	Valley Forge Trailer Pa, PA	FLOODING ON GULPH ROAD BETWEEN VALLEY FORGE PARK ROAD AND THE CHESTER COUNTY LINE. LANE RESTRICTIONS IN PLACE.
Apr 16, 7:30 AM EDT	FLASH FLOOD	Philadelphia, PA	RESCUES AND STUCK VEHICLES REPORTED IN THE AREA OF COBBS CREEK. COBBS CREEK EXCEEDED ITS FLOOD STAGE OF 7 FEET AT 730 AM AND CRESTED AT 7.09 FEET BEFORE QUICKLY FALLING BACK BELOW FLOOD STAGE BY 8 AM.
Apr 16, 7:39 AM EDT	FLOOD	East Lake, NJ	FLOODING ON U.S HIGHWAY 40 AT THE CHESTNUT RUN CROSSING. LANE CLOSURES IN PLACE.
Apr 16, 7:42 AM EDT	FLOOD	1 N Grand Sprute, NJ	FLOODING ON INTERSTATE 295 NEAR EXIT 11...FORCING LANE CLOSURES.
Apr 16, 7:48 AM EDT	FLOOD	White Village, PA	FLOODING ON INTERSTATE 95 ON THE EXIT 6 RAMP NEAR NAAMANS ROAD, FORCING ITS CLOSURE.
Apr 16, 8:00 AM EDT	FLOOD	1 Wnw Treemont Terrace, PA	WATER OVER THE ROAD AT EAST LAFAYETTE STREET AND WALNUT STREET IN NORRISTOWN.
Apr 16, 8:00 AM EDT	FLOOD	Claymont, DE	WATER COVERING THE ROAD AT PHILADELPHIA PIKE AND SEMINOLE AVENUE NEAR THE WATERFALL BANQUET HALL.
Apr 16, 8:13 AM EDT	FLOOD	West Conshohocken, PA	SEVERAL REPORTS OF FLOODING NEAR THE I-76 AND I-476 INTERCHANGE AND SURROUNDING LOCATIONS.
Apr 16, 8:15 AM EDT	FLOOD	Riverside Addition, DE	SEVERAL ACCIDENTS AND LANE CLOSURES ON INTERSTATE 495 IN NEW CASTLE COUNTY OWING TO FLOOD WATERS, INCLUDING NEAR EXIT 5 AND NEAR YALE AVENUE.
Apr 16, 8:15 AM EDT	FLASH FLOOD	Old Mill Pointe, PA	WATER RESCUE REQUIRED AT THE MOUNT ALVERNO ROAD CROSSING OF CHESTER CREEK OWING TO FLASH FLOODING.
Apr 16, 8:30 AM EDT	FLASH FLOOD	Hamilton Park, DE	WATER RESCUE AFTER A CAR WAS STALLED IN 3.5 FEET OF FLOOD WATERS ON PYLES LANE IN NEW CASTLE. ANOTHER RESCUE OCCURRED ON AIRPORT ROAD.
Apr 16, 9:00 AM EDT	FLOOD	Woodbury, NJ	ROAD CLOSURE REPORTED AT S EVERGREEN AVENUE AND GLASSBORO ROAD.
Apr 16, 9:20 AM EDT	FLOOD	Philadelphia, PA	FLOODING REPORTED ON INTERSTATE 76 EASTBOUND NEAR THE GIRARD AVENUE AND MONTGOMERY DRIVE EXITS.
Apr 16, 9:20 AM EDT	FLOOD	Philadelphia, PA	FLOODING REPORTED ON INTERSTATE 95 AT THE ON RAMP NEAR FRONT AND MARKET STREETS.

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, 11.1 hours before the alert went out and 218 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: 1 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 579 m above ground
0-6 km bulk shear: 78 kt
0-1 km storm-relative helicity: 576 m²/s²
0-3 km storm-relative helicity: 680 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted.

986 
WGUS51 KPHI 161104
FFWPHI
DEC003-NJC015-033-PAC029-045-091-101-161500-
/O.NEW.KPHI.FF.W.0001.180416T1104Z-180416T1500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
704 AM EDT MON APR 16 2018

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Northeastern New Castle County in northern Delaware...
  Northern Salem County in southern New Jersey...
  Gloucester County in southern New Jersey...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...
  Philadelphia County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 1100 AM EDT

* At 702 AM EDT...Doppler radar indicated heavy rain across the 
  warned area. Up to three inches of rain has already fallen, with 
  more rain on the way. Flash flooding is expected to begin shortly 
  in the areas of heaviest rain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4017 7555 4021 7512 4018 7509 3999 7506
      3996 7513 3989 7514 3984 7509 3979 7507
      3978 7509 3978 7506 3976 7503 3966 7502
      3957 7558

$$

jjm

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 16, 12:32 AM EDT	Winter Weather Advisory	PHI	Sussex	8 hr
Apr 16, 5:20 AM EDT	Special Marine Warning	PHI		55 min
Apr 16, 5:34 AM EDT	Areal Flood Advisory	PHI	Gloucester, Salem	4 hr
Apr 16, 5:52 AM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester, Mercer	7 hr
Apr 16, 6:07 AM EDT	Special Marine Warning	PHI		53 min
Apr 16, 6:30 AM EDT	Areal Flood Advisory	PHI	Hunterdon	4 hr
Apr 16, 6:45 AM EDT	Special Weather Statement	PHI	Cape May, Cumberland	45 min
Apr 16, 6:49 AM EDT	Special Marine Warning	PHI		86 min
Apr 16, 7:26 AM EDT	Special Weather Statement	PHI	Camden, Gloucester, Mercer	34 min
Apr 16, 7:49 AM EDT	Special Marine Warning	PHI		116 min
Apr 16, 8:13 AM EDT	Special Marine Warning	PHI		62 min
Apr 16, 8:28 AM EDT	Special Weather Statement	PHI	Middlesex, Monmouth, Morris, Somerset, Sussex, Warren	47 min
Apr 16, 9:08 AM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer, Middlesex, Monmouth, Morris, Ocean and 1 more	4 hr
Apr 16, 9:26 AM EDT	Areal Flood Warning	PHI	Burlington, Hunterdon, Mercer, Middlesex, Monmouth, Morris and 3 more	4 hr
Apr 16, 1:18 PM EDT	Coastal Flood Advisory	PHI	Middlesex, Monmouth, Ocean	13 hr
Apr 16, 1:31 PM EDT	Areal Flood Warning	PHI	Burlington, Hunterdon, Mercer, Middlesex, Monmouth, Morris and 2 more	4 hr
Apr 16, 2:45 PM EDT	Coastal Flood Warning	PHI	Burlington, Camden, Gloucester, Mercer	3 hr
Apr 16, 3:52 PM EDT	Small Craft Advisory	PHI		44 hr
Apr 16, 4:46 PM EDT	River Flood Warning	PHI	Somerset	28 hr
Apr 16, 5:27 PM EDT	Areal Flood Warning	PHI	Somerset	8 hr
Apr 16, 7:45 AM EDT	River Flood Warning	PHI	Delaware	4 hr
Apr 16, 8:44 AM EDT	Areal Flood Warning	PHI	Philadelphia	2 hr
Apr 16, 10:45 AM EDT	Areal Flood Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	4 hr
Apr 16, 11:41 AM EDT	River Flood Warning	PHI	Bucks	12 hr
Apr 16, 12:04 PM EDT	Special Weather Statement	PHI	Chester	26 min
Apr 16, 2:27 PM EDT	Areal Flood Warning	PHI	Montgomery, Philadelphia	5 hr
Apr 16, 4:55 AM EDT	Special Weather Statement	PHI	Kent, New Castle	50 min
Apr 16, 6:04 AM EDT	Special Weather Statement	PHI	Kent, Sussex	26 min

Nearby

Flash Flood Warnings in Pennsylvania, 2018 Flash Flood Warnings in New Jersey, 2018 Flash Flood Warnings in Delaware, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.