Alert archive / New Jersey / Flash Flood Warnings in 2020

Flash Flood Warning 61, NWS Philadelphia/Mount Holly

August 13, 2020Middlesex County, Morris County, Somerset County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 13, 2020, 10:01 AM EDT for Middlesex County, Morris County, Somerset County, New Jersey. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 13, 2020, 10:01 AM EDT (14:01 UTC)
Expired
Aug 13, 2020, 12:32 PM EDT
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Middlesex County, NJ, Morris County, NJ, Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 79 km from the middle of the area, began a volume at 14:01 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.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 2.0 hours before the alert went out and 132 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 12:00Z on 2020-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1326 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2020-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 8 square meters per square second.1939Sfc1 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
1326 J/kg
Mixed-layer CIN
-24 J/kg
Mixed-layer LCL
599 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
8 m²/s²
0-3 km storm-relative helicity
26 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

422 
WGUS51 KPHI 131401
FFWPHI
NJC023-027-035-131800-
/O.NEW.KPHI.FF.W.0061.200813T1401Z-200813T1800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1001 AM EDT Thu Aug 13 2020

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Southeastern Morris County in northern New Jersey...
  Northeastern Somerset County in northern New Jersey...
  Northeastern Middlesex County in northern New Jersey...

* Until 200 PM EDT.

* At 1001 AM EDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to two inches of rain have
  already fallen. Flash flooding is ongoing or expected to begin
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar indicated.

  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 could experience flooding include...
  Somerville, Carteret, Madison, Middlesex, Bound Brook, Chatham,
  Mendham, Peapack And Gladstone, Far Hills, Colonia, Martinsville,
  Millington, Basking Ridge, Woodbridge, South Plainfield, North
  Plainfield, Bernardsville, Dunellen, Watchung and Iselin.

Additional rainfall amounts of 1 to 2 inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

&&

LAT...LON 4056 7459 4075 7464 4077 7437 4076 7438
      4075 7436 4074 7437 4067 7446 4066 7445
      4065 7440 4060 7446 4061 7433 4059 7429
      4059 7421 4057 7421

FLASH FLOOD...RADAR INDICATED

$$

JEO
1 follow-up statement
218 
WGUS71 KPHI 131632
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1232 PM EDT Thu Aug 13 2020

NJC023-027-035-131642-
/O.CAN.KPHI.FF.W.0061.000000T0000Z-200813T1800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris NJ-Somerset NJ-Middlesex NJ-
1232 PM EDT Thu Aug 13 2020

...THE FLASH FLOOD WARNING FOR SOUTHEASTERN MORRIS...NORTHEASTERN
SOMERSET AND NORTHEASTERN MIDDLESEX COUNTIES IS CANCELLED...

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

LAT...LON 4056 7459 4075 7464 4077 7437 4076 7438
      4075 7436 4074 7437 4067 7446 4066 7445
      4065 7440 4060 7446 4061 7433 4059 7429
      4059 7421 4057 7421

$$

JEO

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 13, 3:02 AM EDTFlash Flood WatchPHIAtlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 7 more17 hr
Aug 13, 7:47 AM EDTAreal Flood AdvisoryPHIHunterdon, Mercer, Middlesex, Somerset118 min
Aug 13, 8:37 AM EDTFlash Flood WarningPHIHunterdon, Mercer, Middlesex, Somerset3 hr
Aug 13, 9:36 AM EDTAreal Flood AdvisoryPHIHunterdon, Middlesex, Morris, Somerset114 min
Aug 13, 1:06 PM EDTSpecial Weather StatementPHIOcean39 min
Aug 13, 1:30 PM EDTSpecial Weather StatementPHICumberland45 min
Aug 13, 1:56 PM EDTAreal Flood AdvisoryPHIAtlantic, Cape May, Cumberland2 hr
Aug 13, 1:58 PM EDTAreal Flood AdvisoryPHIAtlantic, Burlington, Ocean2 hr
Aug 13, 2:44 PM EDTAreal Flood AdvisoryPHIAtlantic2 hr
Aug 13, 3:54 PM EDTSpecial Weather StatementPHICape May36 min
Aug 13, 4:01 PM EDTAreal Flood AdvisoryPHICape May2 hr
Aug 13, 4:52 PM EDTFlash Flood WarningPHICape May113 min

Nearby

Flash Flood Warnings in New Jersey, 2020Every flash flood warning in 2020

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.