Alert archive / New Jersey / Flash Flood Warnings in 2021

Flash Flood Warning 20, NWS Philadelphia/Mount Holly

July 16, 2021Sussex County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 16, 2021, 5:21 PM EDT for Sussex County, New Jersey. It was in force for 2 hr. 1 report 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: Jul 16, 2021, 5:21 PM EDT (21:21 UTC)
Expired: Jul 16, 2021, 7:26 PM EDT
In force: 2 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Sussex County, NJ

The radar

The Philadelphia radar (KDIX), 146 km from the middle of the area, began a volume at 21:23 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
Jul 16, 6:55 PM EDT	HEAVY RAIN 3.25	Wantage Twp, NJ	STORM TOTAL THROUGH 6:55 PM.

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 12:00Z, 9.4 hours before the alert went out and 163 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: 1044 J/kg
Mixed-layer CIN: -56 J/kg
Mixed-layer LCL: 994 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 108 m²/s²
0-3 km storm-relative helicity: 105 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

856 
WGUS51 KPHI 162121
FFWPHI
NJC037-170115-
/O.NEW.KPHI.FF.W.0020.210716T2121Z-210717T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
521 PM EDT Fri Jul 16 2021

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northern Sussex County in northwestern New Jersey...

* Until 915 PM EDT.

* At 521 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Up to 2 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...
  Sussex, Hainesville, and Vernon Valley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 4127 7484 4130 7456 4122 7440 4120 7453
      4118 7467 4117 7489 4122 7486 4123 7487
      4125 7486 4125 7485

FLASH FLOOD...RADAR INDICATED

$$

Robertson

2 follow-up statements

120 
WGUS71 KPHI 162155
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
555 PM EDT Fri Jul 16 2021

NJC037-170115-
/O.CON.KPHI.FF.W.0020.000000T0000Z-210717T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex NJ-
555 PM EDT Fri Jul 16 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 915 PM EDT THIS 
EVENING FOR NORTHERN SUSSEX COUNTY...

At 555 PM EDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Over 2 inches of rain has fallen in 
some areas with additional rainfall occurring. 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...
  Sussex, Hainesville, and Vernon Valley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 4127 7484 4130 7456 4122 7440 4120 7453
      4118 7467 4117 7489 4122 7486 4123 7487
      4125 7486 4125 7485

FLASH FLOOD...RADAR INDICATED

$$

Robertson

019 
WGUS71 KPHI 162326
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
726 PM EDT Fri Jul 16 2021

NJC037-162336-
/O.CAN.KPHI.FF.W.0020.000000T0000Z-210717T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Sussex NJ-
726 PM EDT Fri Jul 16 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHERN SUSSEX COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures. Additional
showers and thunderstorms are possible through this evening.

LAT...LON 4127 7484 4130 7456 4122 7440 4120 7453
      4118 7467 4117 7489 4122 7486 4123 7487
      4125 7486 4125 7485

$$

Robertson

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 16, 2:55 PM EDT	Areal Flood Advisory	PHI	Sussex	4 hr
Jul 16, 3:17 PM EDT	Flash Flood Watch	PHI	Atlantic, Burlington, Camden, Gloucester, Hunterdon, Mercer and 8 more	35 hr
Jul 16, 5:01 PM EDT	Areal Flood Advisory	PHI	Sussex	2 hr
Jul 16, 5:25 PM EDT	Special Weather Statement	PHI	Sussex	35 min
Jul 16, 5:29 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	46 min
Jul 16, 5:34 PM EDT	Areal Flood Advisory	PHI	Sussex, Warren	112 min
Jul 16, 6:10 PM EDT	Special Weather Statement	PHI	Warren	35 min
Jul 16, 6:14 PM EDT	Special Weather Statement	PHI	Sussex	31 min
Jul 16, 6:27 PM EDT	Areal Flood Advisory	PHI	Sussex	59 min
Jul 16, 6:46 PM EDT	Special Weather Statement	PHI	Warren	29 min
Jul 16, 7:10 PM EDT	Special Weather Statement	PHI	Warren	35 min

Nearby

Flash Flood Warnings in New Jersey, 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.