Alert archive / New Jersey / Areal Flood Warnings in 2021

Areal Flood Warning 39, NWS Philadelphia/Mount Holly

September 2, 2021Morris County, Somerset County, New Jersey

NWS Philadelphia/Mount Holly issued this areal flood warning at Sep 2, 2021, 1:52 AM EDT for Morris County, Somerset County, New Jersey. It was in force for 13 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
Sep 2, 2021, 1:52 AM EDT (05:52 UTC)
Expired
Sep 2, 2021, 3:00 PM EDT
In force
13 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Morris County, NJ, Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 106 km from the middle of the area, began a volume at 05:54 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

TimeReportWhereRemark
Sep 2, 5:00 AM EDTFLOOD1 Ese Boonton, NJTHE GAUGE ON THE ROCKAWAY RIVER AT BOONTON BELOW RESERVOIR (BONN4) REACHED FLOOD STAGE AT 500 AM 9/2, CRESTING AT 7.03 FEET (MODERATE FLOODING) AT 715 PM 9/2.

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, 5.9 hours before the alert went out and 136 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-pSkew-T log-p diagram, Brookhaven, NY at 00:00Z on 2021-09-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 123 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 00:00Z on 2021-09-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 279 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
123 J/kg
Mixed-layer CIN
-47 J/kg
Mixed-layer LCL
512 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
279 m²/s²
0-3 km storm-relative helicity
456 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.2

Open this sounding in Storm Lab

The text

As transmitted.

298 
WGUS41 KPHI 020552
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
152 AM EDT Thu Sep 2 2021

NJC027-035-021600-
/O.NEW.KPHI.FA.W.0039.210902T0552Z-210902T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris NJ-Somerset NJ-
152 AM EDT Thu Sep 2 2021

The National Weather Service in Mount Holly has issued a

* Flood Warning for...
  Morris County in northern New Jersey...
  North Central Somerset County in northern New Jersey...

* Until noon EDT Thursday.

* At 152 AM EDT, local law enforcement reported widespread flooding 
  in the warning area. Several roads are closed, and the Whippany 
  River remains in flood. Avoid unnecessary travel in this area.

* Some locations that may experience flooding include...
  Morristown, Dover, Madison, Hopatcong, Florham Park, East Hanover, 
  Lincoln Park, Kinnelon, Chatham, Boonton, Butler, and Wharton.

This includes the following highways...
	Interstate 80 in New Jersey between mile markers 27 and 48.
	Interstate 287 in New Jersey between mile markers 30 and 53.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4074 7477 4077 7485 4090 7471 4092 7465
      4096 7464 4108 7450 4103 7450 4105 7445
      4104 7443 4102 7443 4100 7430 4097 7428
      4090 7429 4091 7433 4087 7434 4086 7432
      4079 7437 4076 7438 4076 7436 4072 7439

$$

CMS
2 follow-up statements
102 
WGUS41 KPHI 021512
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
1112 AM EDT Thu Sep 2 2021

NJC027-035-021900-
/O.EXT.KPHI.FA.W.0039.000000T0000Z-210902T1900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris NJ-Somerset NJ-
1112 AM EDT Thu Sep 2 2021

The National Weather Service in Mount Holly has extended the

* Flood Warning for...
  Morris County in northern New Jersey...
  North Central Somerset County in northern New Jersey...

* Until 300 PM EDT.

* At 1112 AM EDT, gauge reports indicated heavy rain due to 
  thunderstorms. Flooding is already occurring in the warned area.

* For Rockaway River at Boonton Below Resvr:
  At 10:00am the stage was 6.39 feet.
  Flood Stage is 5 feet.
  ...
  For Rockaway River at Boonton Above Resvr:
  At 11:00am the stage was 4.11 feet.
  Flood Stage is 4.5 feet.
  ...
  For Passaic River at Chatham:
  At 10:15am the stage was 6.58 feet.
  Flood Stage is 6 feet.
  ...
  For Pequannock River at Oak Ridge:
  At 10:15am the stage was 7.41 feet.
  Flood Stage is 10.5 feet.
  ...
  For Pompton River at Pompton Plains:
  At 10:15am the stage was 19.5 feet.
  Flood Stage is 16 feet.
  ...
  For Green Pond Brook at Picatinny:
  At 10:30am the stage was 2.55 feet.
  Flood Stage is 3 feet.
  ...
  For Whippany River at Pine Brook:
  At 11:02am the stage was 8.61 feet.
  Flood Stage is 9 feet.
  ...
  For Whippany River at Morristown:
  At 10:10am the stage was 6.65 feet.
  Flood Stage is 6 feet.

This includes the following highways...
	Interstate 80 in New Jersey between mile markers 27 and 48.
	Interstate 287 in New Jersey between mile markers 30 and 53.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4074 7477 4077 7485 4090 7471 4092 7465
      4096 7464 4108 7450 4103 7450 4105 7445
      4104 7443 4102 7443 4100 7430 4097 7428
      4090 7429 4091 7433 4087 7434 4086 7432
      4079 7437 4076 7438 4076 7436 4072 7439

$$

Kruzdlo
214 
WGUS81 KPHI 021854
FLSPHI

Flood Statement
National Weather Service Mount Holly NJ
254 PM EDT Thu Sep 2 2021

NJC027-035-021904-
/O.EXP.KPHI.FA.W.0039.000000T0000Z-210902T1900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris NJ-Somerset NJ-
254 PM EDT Thu Sep 2 2021

...FLOOD WARNING WILL EXPIRE AT 3 PM EDT THIS AFTERNOON FOR MORRIS 
AND NORTH CENTRAL SOMERSET COUNTIES...

This flood warning will be allowed to expire. There are additional 
flood warnings still in effect across the region.

LAT...LON 4074 7477 4077 7485 4090 7471 4092 7465
      4096 7464 4108 7450 4103 7450 4105 7445
      4104 7443 4102 7443 4100 7430 4097 7428
      4090 7429 4091 7433 4087 7434 4086 7432
      4079 7437 4076 7438 4076 7436 4072 7439

$$

Kruzdlo

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 1, 8:02 PM EDTFlash Flood Warning EmergencyCatastrophic damage threatPHIMiddlesex, Morris, Somerset5 hr
Sep 1, 9:01 PM EDTFlash Flood WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean5 hr
Sep 1, 9:43 PM EDTRiver Flood WarningPHIMercer33 hr
Sep 1, 10:05 PM EDTFlash Flood Warning Considerable damage threatPHIMorris, Somerset4 hr
Sep 1, 10:23 PM EDTCoastal Flood StatementPHIOcean13 hr
Sep 1, 10:24 PM EDTFlash Flood WarningPHIBurlington, Camden, Gloucester4 hr
Sep 1, 10:29 PM EDTRiver Flood WarningPHIHunterdon, Mercer49 hr
Sep 1, 10:32 PM EDTRiver Flood WarningPHIMercer31 hr
Sep 1, 10:35 PM EDTRiver Flood WarningPHIBergen, Morris, Passaic30 hr
Sep 1, 10:37 PM EDTRiver Flood WarningPHIMorris, Passaic41 hr
Sep 1, 10:38 PM EDTRiver Flood WarningPHIMorris, Somerset21 days
Sep 1, 10:47 PM EDTAreal Flood WarningPHIWarren23 hr
Sep 1, 10:52 PM EDTAreal Flood WarningPHIHunterdon, Warren12 hr
Sep 2, 12:01 AM EDTAreal Flood WarningPHIHunterdon, Morris, Sussex, Warren40 hr
Sep 2, 12:28 AM EDTAreal Flood AdvisoryPHIAtlantic, Burlington, Camden, Gloucester3 hr
Sep 2, 12:31 AM EDTAreal Flood AdvisoryPHIMonmouth, Ocean2 hr
Sep 2, 1:38 AM EDTAreal Flood WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean4 hr
Sep 2, 2:23 AM EDTAreal Flood WarningPHIBurlington, Camden, Gloucester, Salem9 hr
Sep 2, 2:29 AM EDTAreal Flood WarningPHIBurlington, Camden, Gloucester5 hr
Sep 2, 3:52 AM EDTAreal Flood WarningPHIHunterdon, Mercer, Morris, Somerset, Warren8 hr
Sep 2, 3:53 AM EDTAreal Flood WarningPHIHunterdon, Mercer, Middlesex, Morris, Somerset8 hr
Sep 2, 4:00 AM EDTRiver Flood WarningPHIMorris48 hr
Sep 2, 4:45 AM EDTRiver Flood WarningPHIHunterdon, Mercer37 hr
Sep 2, 4:45 AM EDTRiver Flood WarningPHIHunterdon, Warren37 hr
Sep 2, 4:45 AM EDTRiver Flood WarningPHIHunterdon37 hr
Sep 2, 4:45 AM EDTRiver Flood WarningPHIHunterdon33 hr
Sep 2, 4:45 AM EDTRiver Flood WarningPHIHunterdon, Mercer34 hr
Sep 2, 4:45 AM EDTRiver Flood WarningPHISussex, Warren5 hr
Sep 2, 6:05 AM EDTCoastal Flood WarningPHIBurlington, Camden, Gloucester, Mercer6 hr
Sep 2, 1:20 PM EDTAreal Flood WarningPHIMiddlesex21 hr
Sep 2, 6:44 PM EDTCoastal Flood AdvisoryPHIBurlington, Camden, Gloucester7 hr

Nearby

Areal Flood Warnings in New Jersey, 2021Every areal 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.