Alert archive / New Jersey / Flash Flood Warnings in 2021

Flash Flood Warning 34, NWS Philadelphia/Mount Holly

August 10, 2021Burlington County, Mercer County, New Jersey; Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 10, 2021, 5:58 AM EDT for Burlington County, Mercer County, New Jersey; Bucks County, Pennsylvania. It was in force for 2 hr. 3 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 10, 2021, 5:58 AM EDT (09:58 UTC)
Expired: Aug 10, 2021, 8:00 AM EDT
In force: 2 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Burlington County, NJ, Mercer County, NJ, Bucks County, PA

The radar

The Philadelphia radar (KDIX), 42 km from the middle of the area, began a volume at 09:58 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 10, 5:58 AM EDT	FLASH FLOOD	2 Wnw Columbus, NJ	FLOODING ON I-295 NORTHBOUND RAMP TO EXIT 52 - COLUMBUS RD (MANSFIELD TWP) ALL LANES CLOSED RAMP CLOSED AND DETOURED.
Aug 10, 6:07 AM EDT	FLASH FLOOD	Columbus, NJ	FLOODING ON US 206 SOUTHBOUND CR 678/CR 690 (MANSFIELD TWP) ALL LANES CLOSED AND DETOURED.
Aug 10, 6:18 AM EDT	FLASH FLOOD	1 Wsw Bordentown Twp, NJ	FLOODING ON I-295 SOUTHBOUND SOUTH OF EXIT 57 - US 130 (BORDENTOWN TWP) ALL LANES CLOSED AND DETOURED.

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 10.0 hours before the alert went out and 185 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: 195 J/kg
Mixed-layer CIN: -69 J/kg
Mixed-layer LCL: 589 m above ground
0-6 km bulk shear: 8 kt
0-1 km storm-relative helicity: -3 m²/s²
0-3 km storm-relative helicity: -23 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

298 
WGUS51 KPHI 100958
FFWPHI
NJC005-021-PAC017-101200-
/O.NEW.KPHI.FF.W.0034.210810T0958Z-210810T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
558 AM EDT Tue Aug 10 2021

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Southwestern Mercer County in central New Jersey...
  North Central Burlington County in southern New Jersey...
  Southeastern Bucks County in southeastern Pennsylvania...

* Until 800 AM EDT.

* At 558 AM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1.5 and 3 inches of 
  rain have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets, and underpasses as well as other
           drainage and low lying areas.

* Some locations that will experience flash flooding include...
  Trenton, Ewing, Florence, Burlington, Bristol, Mount Holly, 
  Bordentown, Yardley, Newtown, Tullytown, Langhorne, and Pemberton.

This includes the following highways...
	New Jersey Turnpike between exits 5 and 7A.
	Pennsylvania Turnpike between mile markers 353 and 359.
	Interstate 95 in Pennsylvania between mile markers 38 and 40.
	Interstate 295 in New Jersey between mile markers 47 and 61...and
	near mile marker 76.
	Interstate 195 in New Jersey between mile markers 0 and 1.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Motorists should not attempt to drive around barricades or drive 
cars through flooded areas.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 4014 7496 4018 7504 4022 7507 4025 7506
      4027 7504 4030 7497 4028 7487 4025 7478
      4011 7459 4003 7457 4000 7458 3998 7459
      3996 7468 4000 7480

FLASH FLOOD...RADAR INDICATED

$$

Deal

1 follow-up statement

381 
WGUS71 KPHI 101151
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
751 AM EDT Tue Aug 10 2021

NJC005-021-PAC017-101201-
/O.EXP.KPHI.FF.W.0034.000000T0000Z-210810T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Burlington NJ-Mercer NJ-Bucks PA-
751 AM EDT Tue Aug 10 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 8 AM EDT THIS MORNING FOR 
SOUTHWESTERN MERCER, NORTH CENTRAL BURLINGTON, AND SOUTHEASTERN 
BUCKS COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 4014 7496 4018 7504 4022 7507 4025 7506
      4027 7504 4030 7497 4028 7487 4025 7478
      4011 7459 4003 7457 4000 7458 3998 7459
      3996 7468 4000 7480

$$

Iovino

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 10, 1:02 AM EDT	Special Weather Statement	PHI	Burlington	28 min
Aug 10, 3:33 AM EDT	Excessive Heat Warning	PHI	Burlington, Camden, Gloucester, Hunterdon, Mercer, Middlesex and 5 more	4 days
Aug 10, 3:33 AM EDT	Heat Advisory	PHI	Atlantic, Cape May, Cumberland, Monmouth, Ocean, Salem and 2 more	4 days
Aug 10, 3:54 AM EDT	Areal Flood Advisory	PHI	Atlantic	80 min
Aug 10, 4:59 AM EDT	Areal Flood Advisory	PHI	Burlington	60 min
Aug 10, 2:07 PM EDT	Special Weather Statement	PHI	Salem	38 min
Aug 10, 4:52 PM EDT	Special Weather Statement	PHI	Monmouth	23 min
Aug 10, 4:54 PM EDT	Special Marine Warning	PHI		26 min
Aug 10, 5:05 PM EDT	Special Weather Statement	PHI	Somerset, Warren	25 min
Aug 10, 5:09 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Hunterdon, Mercer, Somerset, Warren	51 min
Aug 10, 5:30 PM EDT	Special Weather Statement	PHI	Warren	30 min
Aug 10, 5:58 PM EDT	Special Weather Statement	PHI	Mercer, Middlesex, Morris, Somerset, Warren	32 min
Aug 10, 6:27 PM EDT	Special Weather Statement	PHI	Burlington, Mercer, Middlesex, Monmouth, Morris	33 min
Aug 10, 6:59 PM EDT	Special Weather Statement	PHI	Middlesex, Monmouth	31 min
Aug 10, 7:09 PM EDT	Special Marine Warning	PHI		66 min
Aug 10, 7:27 PM EDT	Special Weather Statement	PHI	Monmouth	33 min
Aug 9, 10:10 PM EDT	Areal Flood Advisory	PHI	Carbon	3 hr
Aug 10, 3:06 PM EDT	Special Weather Statement	PHI	Berks	24 min
Aug 10, 3:33 PM EDT	Special Weather Statement	PHI	Berks	27 min
Aug 10, 3:52 PM EDT	Special Weather Statement	PHI	Berks, Carbon, Lehigh	23 min
Aug 10, 4:01 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Carbon, Chester, Lehigh, Montgomery, Northampton	44 min
Aug 10, 4:18 PM EDT	Areal Flood Advisory	PHI	Berks, Carbon, Lehigh	3 hr
Aug 10, 4:33 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Carbon, Chester, Lehigh, Monroe and 2 more	42 min
Aug 10, 5:11 PM EDT	Special Weather Statement	PHI	Chester, Montgomery, Philadelphia	34 min
Aug 10, 5:40 PM EDT	Special Weather Statement	PHI	Chester	35 min
Aug 10, 6:36 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester	39 min
Aug 10, 7:10 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	65 min
Aug 10, 7:54 PM EDT	Severe Thunderstorm Warning Considerable damage threat	PHI	Chester	51 min

Nearby

Flash Flood Warnings in New Jersey, 2021 Flash Flood Warnings in Pennsylvania, 2021 Every flash flood warning in 2021

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.