Alert archive / New Jersey / Flash Flood Warnings in 2021

Flash Flood Warning 81, NWS Philadelphia/Mount Holly

September 8, 2021Warren County, New Jersey; Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 8, 2021, 10:42 PM EDT for Warren County, New Jersey; Northampton County, Pennsylvania. It was in force for 6 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: Sep 8, 2021, 10:42 PM EDT (02:42 UTC)
Expired: Sep 9, 2021, 4:30 AM EDT
In force: 6 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Warren County, NJ, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 112 km from the middle of the area, began a volume at 02:43 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
Sep 8, 11:24 PM EDT	HEAVY RAIN 2.12	Forks Twp, PA	IN 1.5 HOURS.
Sep 9, 1:15 AM EDT	FLASH FLOOD	2 E Tatamy, PA	WATER RESCUE AT KUEBLER AND GLOVER ROADS IN FORKS TOWNSHIP. TIME ESTIMATED.
Sep 9, 1:50 AM EDT	FLASH FLOOD	2 Sse Columbia, NJ	FLOODING ON US 46 IN BOTH DIRECTIONS IN THE AREA OF NJ 163. ALL LANES CLOSED. TIME BASED ON DISPATCH REPORT.

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, 2.7 hours before the alert went out and 188 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: 619 J/kg
Mixed-layer CIN: -36 J/kg
Mixed-layer LCL: 807 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 211 m²/s²
0-3 km storm-relative helicity: 225 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 3.4

Open this sounding in Storm Lab

The text

As transmitted.

209 
WGUS51 KPHI 090242
FFWPHI
NJC041-PAC095-090830-
/O.NEW.KPHI.FF.W.0081.210909T0242Z-210909T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1042 PM EDT Wed Sep 8 2021

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Warren County in northwestern New Jersey...
  Eastern Northampton County in eastern Pennsylvania...

* Until 430 AM EDT.

* At 1042 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1.5 inches of 
  rain have fallen. Additional rainfall amounts of 1 to 2 inches are 
  possible in the warned area. 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 may experience flash flooding include...
  Easton, Bethlehem, Forks, Hackettstown, Wilson, Washington, 
  Blairstown, Nazareth, Bangor, Pen Argyl, Wind Gap, and Belvidere.

This includes the following highways...
	Interstate 78 in Pennsylvania between mile markers 71 and 76.
	Interstate 78 in New Jersey between mile markers 0 and 7.
	Interstate 80 in New Jersey between mile markers 1 and 22.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4060 7522 4064 7540 4070 7528 4083 7539
      4086 7529 4090 7523 4093 7521 4096 7513
      4099 7513 4104 7503 4109 7497 4091 7477
      4088 7481 4086 7480 4082 7484 4078 7490
      4071 7497 4063 7515 4059 7518 4061 7520

FLASH FLOOD...RADAR INDICATED

$$

Iovino

2 follow-up statements

827 
WGUS71 KPHI 090611
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
211 AM EDT Thu Sep 9 2021

NJC041-PAC095-090830-
/O.CON.KPHI.FF.W.0081.000000T0000Z-210909T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Warren NJ-Northampton PA-
211 AM EDT Thu Sep 9 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 430 AM EDT EARLY THIS 
MORNING FOR WARREN AND EASTERN NORTHAMPTON COUNTIES...

At 211 AM EDT, Doppler radar indicated heavy rain across the warned 
area. Between 1.5 and 4 inches of rain have fallen. Additional 
rainfall amounts up to 0.5 inches are possible in the warned area. 
Flash flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by heavy rain.

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 may experience flash flooding include...
  Easton, Bethlehem, Forks, Hackettstown, Wilson, Washington, 
  Blairstown, Nazareth, Bangor, Pen Argyl, Wind Gap, and Belvidere.

This includes the following highways...
	Interstate 78 in Pennsylvania between mile markers 71 and 76.
	Interstate 78 in New Jersey between mile markers 0 and 7.
	Interstate 80 in New Jersey between mile markers 1 and 22.

Although the heaviest rain has left the warned area, it will take 
time for the runoff to recede. Any additional rainfall, even light 
rain, will exacerbate any flooding that is ongoing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4060 7522 4064 7540 4070 7528 4083 7539
      4086 7529 4090 7523 4093 7521 4096 7513
      4099 7513 4104 7503 4109 7497 4091 7477
      4088 7481 4086 7480 4082 7484 4078 7490
      4071 7497 4063 7515 4059 7518 4061 7520

FLASH FLOOD...RADAR INDICATED

$$

SFJ

974 
WGUS71 KPHI 090828
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
428 AM EDT Thu Sep 9 2021

NJC041-PAC095-090838-
/O.EXP.KPHI.FF.W.0081.000000T0000Z-210909T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Warren NJ-Northampton PA-
428 AM EDT Thu Sep 9 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 430 AM EDT EARLY THIS MORNING 
FOR WARREN AND EASTERN NORTHAMPTON COUNTIES...

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

LAT...LON 4060 7522 4064 7540 4070 7528 4083 7539
      4086 7529 4090 7523 4093 7521 4096 7513
      4099 7513 4104 7503 4109 7497 4091 7477
      4088 7481 4086 7480 4082 7484 4078 7490
      4071 7497 4063 7515 4059 7518 4061 7520

$$

SFJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 8, 9:16 PM EDT	Areal Flood Advisory	PHI	Warren	3 hr
Sep 8, 9:16 PM EDT	Special Weather Statement	PHI	Sussex, Warren	29 min
Sep 8, 9:43 PM EDT	Special Weather Statement	PHI	Sussex, Warren	47 min
Sep 8, 10:56 PM EDT	Special Weather Statement	PHI	Warren	34 min
Sep 8, 11:27 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Warren	48 min
Sep 8, 11:30 PM EDT	Areal Flood Advisory	PHI	Morris, Sussex	4 hr
Sep 9, 12:07 AM EDT	Special Weather Statement	PHI	Hunterdon, Somerset, Warren	23 min
Sep 9, 12:18 AM EDT	Special Marine Warning	PHI		57 min
Sep 9, 12:30 AM EDT	Special Weather Statement	PHI	Morris	30 min
Sep 9, 12:41 AM EDT	Special Marine Warning	PHI		52 min
Sep 9, 2:17 AM EDT	Special Weather Statement	PHI	Ocean	28 min
Sep 9, 2:46 AM EDT	Special Weather Statement	PHI	Atlantic	29 min
Sep 9, 3:14 AM EDT	Special Weather Statement	PHI	Atlantic	31 min
Sep 9, 3:30 AM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Cape May, Cumberland	112 min
Sep 9, 4:28 AM EDT	Areal Flood Warning	PHI	Warren	4 hr
Sep 8, 8:47 PM EDT	Special Weather Statement	PHI	Northampton	28 min
Sep 8, 9:12 PM EDT	Special Weather Statement	PHI	Lehigh	48 min
Sep 8, 9:38 PM EDT	Special Weather Statement	PHI	Berks	52 min
Sep 8, 9:46 PM EDT	Special Weather Statement	PHI	Lehigh, Northampton	44 min
Sep 8, 9:48 PM EDT	Flash Flood Warning	PHI	Lehigh, Northampton	7 hr
Sep 8, 9:59 PM EDT	Areal Flood Advisory	PHI	Berks	3 hr
Sep 8, 10:11 PM EDT	Severe Thunderstorm Warning	PHI	Berks	49 min
Sep 8, 10:23 PM EDT	Tornado Warning	PHI	Berks	22 min
Sep 8, 10:27 PM EDT	Special Weather Statement	PHI	Northampton	33 min
Sep 8, 10:47 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	3 hr
Sep 8, 10:47 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh, Montgomery, Northampton	58 min
Sep 8, 11:35 PM EDT	Special Weather Statement	PHI	Chester, Delaware, Montgomery	40 min
Sep 9, 12:08 AM EDT	Special Weather Statement	PHI	Bucks, Delaware, Montgomery, Philadelphia	37 min
Sep 9, 4:26 AM EDT	Areal Flood Warning	PHI	Lehigh, Northampton	3 hr

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.