Alert archive / New Jersey / Areal Flood Warnings in 2021

Areal Flood Warning 3, NWS Philadelphia/Mount Holly

March 24, 2021Hunterdon County, Mercer County, Somerset County, New Jersey

NWS Philadelphia/Mount Holly issued this areal flood warning at Mar 24, 2021, 8:12 PM EDT for Hunterdon County, Mercer County, Somerset County, New Jersey. It was in force for 4 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
Mar 24, 2021, 8:12 PM EDT (00:12 UTC)
Expired
Mar 25, 2021, 12:15 AM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Hunterdon County, NJ, Mercer County, NJ, Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 61 km from the middle of the area, began a volume at 00:11 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
Mar 24, 8:15 PM EDTFLOOD3 Ne Ringoes, NJTHE NESHANIC RIVER AT REAVILLE (REAN4) REACHED MINOR FLOOD STAGE AT 815 PM, CRESTING AT 7.24 FEET AT 915 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 00:00Z, 0.2 hours before the alert went out and 172 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 2021-03-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 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 00:00Z on 2021-03-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 209 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
4 J/kg
Mixed-layer CIN
-48 J/kg
Mixed-layer LCL
510 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
209 m²/s²
0-3 km storm-relative helicity
270 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

713 
WGUS41 KPHI 250012
FLWPHI

BULLETIN - EAS ACTIVATION REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
812 PM EDT Wed Mar 24 2021

NJC019-021-035-250415-
/O.NEW.KPHI.FA.W.0003.210325T0012Z-210325T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Mercer NJ-Somerset NJ-
812 PM EDT Wed Mar 24 2021

The National Weather Service in Mount Holly has issued a

* Flood Warning for...
  Northwestern Mercer County in central New Jersey...
  Southwestern Somerset County in northern New Jersey...
  Southeastern Hunterdon County in northwestern New Jersey...

* Until 1215 AM EDT.

* At 812 PM EDT, Doppler radar and automated rain gauges indicated 
  heavy rain. Flooding is ongoing or expected to begin shortly in 
  the warned area. Between 1 and 1.5 inches of rain have fallen.

* Flooding is expected along the Neshanic River near Reaville.

Some locations that may experience flooding include...
  Ewing, Princeton, Flemington, Pennington, Hopewell, Skillman, 
  Cloverhill, Lawrenceville, and Princeton North.

This includes the following highways...
	Interstate 295 in New Jersey between mile markers 72 and 74.

Additional rainfall amounts up to 0.5 inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4050 7491 4050 7479 4043 7464 4031 7470
      4028 7481 4032 7488

$$

SFJ
2 follow-up statements
715 
WGUS81 KPHI 250228
FLSPHI

Flood Statement
National Weather Service Mount Holly NJ
1028 PM EDT Wed Mar 24 2021

NJC019-021-035-250415-
/O.CON.KPHI.FA.W.0003.000000T0000Z-210325T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Mercer NJ-Somerset NJ-
1028 PM EDT Wed Mar 24 2021

...FLOOD WARNING REMAINS IN EFFECT UNTIL 1215 AM EDT THURSDAY FOR 
NORTHWESTERN MERCER, SOUTHWESTERN SOMERSET, AND SOUTHEASTERN 
HUNTERDON COUNTIES...

At 1028 PM EDT, gauge reports indicated minor flooding is occurring 
along the Neshanic River near Reaville. Between 1 and 2 inches of 
rain have fallen.

For Neshanic at Reaville:
At 10:15pm the stage was 7.02 feet.
Flood Stage is 6.5 feet.

This includes the following highways...
	Interstate 295 in New Jersey between mile markers 72 and 74.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4050 7491 4050 7479 4043 7464 4031 7470
      4028 7481 4032 7488

$$

SFJ
468 
WGUS81 KPHI 250407
FLSPHI

Flood Statement
National Weather Service Mount Holly NJ
1207 AM EDT Thu Mar 25 2021

NJC019-021-035-250417-
/O.EXP.KPHI.FA.W.0003.000000T0000Z-210325T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Mercer NJ-Somerset NJ-
1207 AM EDT Thu Mar 25 2021

...FLOOD WARNING WILL EXPIRE AT 1215 AM EDT EARLY THIS MORNING FOR 
NORTHWESTERN MERCER, SOUTHWESTERN SOMERSET, AND SOUTHEASTERN 
HUNTERDON COUNTIES...

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

LAT...LON 4050 7491 4050 7479 4043 7464 4031 7470
      4028 7481 4032 7488

$$

CMS

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 25, 3:13 AM EDTSmall Craft AdvisoryPHI48 hr
Mar 25, 11:00 AM EDTWind AdvisoryPHIAtlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 10 more32 hr
Mar 25, 6:25 PM EDTMarine Dense Fog AdvisoryPHI10 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.