Alert archive / New Jersey / Areal Flood Warnings in 2021

Areal Flood Warning 11, NWS Philadelphia/Mount Holly

July 17, 2021Somerset County, New Jersey

NWS Philadelphia/Mount Holly issued this areal flood warning at Jul 17, 2021, 11:26 PM EDT for Somerset County, New Jersey. It was in force for 10 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
Jul 17, 2021, 11:26 PM EDT (03:26 UTC)
Expired
Jul 18, 2021, 9:00 AM EDT
In force
10 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

County Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 71 km from the middle of the area, began a volume at 03:30 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 00:00Z, 3.4 hours before the alert went out and 159 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 2021-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1431 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 2021-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 26 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
1431 J/kg
Mixed-layer CIN
-48 J/kg
Mixed-layer LCL
988 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
26 m²/s²
0-3 km storm-relative helicity
54 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.6

Open this sounding in Storm Lab

The text

As transmitted.

532 
WGUS41 KPHI 180326
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
1126 PM EDT Sat Jul 17 2021

NJC035-181300-
/O.NEW.KPHI.FA.W.0011.210718T0326Z-210718T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Somerset NJ-
1126 PM EDT Sat Jul 17 2021

The National Weather Service in Mount Holly has issued a

* Flood Warning for...
  Southwestern Somerset County in northern New Jersey...

* Until 900 AM EDT Sunday.

* At 1126 PM EDT, rainfall totals were between 3 and 5 inches in 
  much of southwestern Somerset County. While little additional 
  rainfall is expected overnight, runoff from the heavy rain will 
  continue to cause flooding in the area until Sunday morning.

* Some locations that are experiencing flooding include...
  Somerville, Bridgewater, Manville, Rocky Hill, Millstone, 
  Flagtown, Belle Mead, Skillman, Cloverhill, and Raritan.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4061 7471 4061 7464 4060 7463 4057 7461
      4045 7458 4040 7462 4041 7474 4051 7480
      4051 7479 4050 7478 4051 7477 4055 7474
      4057 7473 4058 7471 4059 7472 4060 7472

$$

Iovino

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 17, 8:00 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden, Mercer, Monmouth45 min
Jul 17, 8:09 PM EDTFlash Flood WarningPHIMercer, Somerset4 hr
Jul 17, 8:35 PM EDTSevere Thunderstorm WarningPHIAtlantic, Burlington, Camden, Gloucester40 min
Jul 17, 8:36 PM EDTSevere Thunderstorm WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean, Somerset54 min
Jul 17, 8:46 PM EDTSpecial Marine WarningPHI59 min
Jul 17, 8:53 PM EDTAreal Flood AdvisoryPHIMercer, Middlesex, Monmouth3 hr
Jul 17, 9:25 PM EDTAreal Flood AdvisoryPHIBurlington, Camden, Gloucester, Salem2 hr
Jul 17, 9:27 PM EDTSevere Thunderstorm WarningPHIGloucester, Salem48 min
Jul 17, 9:30 PM EDTSevere Thunderstorm WarningPHICape May29 min
Jul 17, 9:36 PM EDTFlash Flood WarningPHICamden, Gloucester, Salem2 hr
Jul 17, 9:44 PM EDTSpecial Marine WarningPHI61 min
Jul 17, 9:48 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden, Gloucester, Mercer, Salem42 min
Jul 17, 10:21 PM EDTSevere Thunderstorm WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean54 min
Jul 17, 10:22 PM EDTTornado WarningPHIBurlington, Monmouth, Ocean23 min
Jul 17, 10:27 PM EDTSpecial Weather StatementPHIBurlington, Camden33 min
Jul 17, 10:38 PM EDTTornado WarningPHIBurlington, Monmouth, Ocean16 min
Jul 17, 10:43 PM EDTFlash Flood WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean79 min
Jul 17, 10:47 PM EDTSpecial Marine WarningPHI118 min
Jul 17, 10:51 PM EDTSpecial Marine WarningPHI114 min
Jul 17, 11:07 PM EDTSpecial Weather StatementPHIMiddlesex38 min
Jul 17, 11:08 PM EDTAreal Flood WarningPHIHunterdon12 hr
Jul 17, 11:11 PM EDTSpecial Weather StatementPHIMonmouth, Ocean34 min
Jul 17, 11:20 PM EDTSpecial Marine WarningPHI115 min
Jul 18, 2:41 AM EDTAreal Flood WarningPHIMercer4 hr
Jul 18, 3:48 AM EDTRiver Flood WarningPHIMercer3 hr
Jul 18, 9:08 AM EDTAreal Flood WarningPHISomerset2 hr
Jul 18, 11:03 AM EDTRiver Flood WarningPHIMiddlesex, Somerset88 min

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.