Alert archive / Pennsylvania / Flash Flood Warnings in 2023

Flash Flood Warning 60, NWS Philadelphia/Mount Holly

July 16, 2023Hunterdon County, Warren County, New Jersey; 6 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 16, 2023, 4:05 AM EDT for Hunterdon County, Warren County, New Jersey; 6 counties in Pennsylvania. It was in force for 6 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 16, 2023, 4:05 AM EDT (08:05 UTC)
Expired: Jul 16, 2023, 9:36 AM EDT
In force: 6 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Hunterdon County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Chester County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 103 km from the middle of the area, began a volume at 08:08 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, 8.1 hours before the alert went out and 221 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: 1061 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 624 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 63 m²/s²
0-3 km storm-relative helicity: 29 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.0

Open this sounding in Storm Lab

The text

As transmitted.

620 
WGUS51 KPHI 160805
FFWPHI
NJC019-041-PAC011-017-029-077-091-095-161215-
/O.NEW.KPHI.FF.W.0060.230716T0805Z-230716T1215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
405 AM EDT Sun Jul 16 2023

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northwestern Hunterdon County in northwestern New Jersey...
  Southwestern Warren County in northwestern New Jersey...
  East Central Berks County in eastern Pennsylvania...
  Southeastern Lehigh County in eastern Pennsylvania...
  Southeastern Northampton County in eastern Pennsylvania...
  Northwestern Bucks County in southeastern Pennsylvania...
  North Central Chester County in southeastern Pennsylvania...
  Northwestern Montgomery County in southeastern Pennsylvania...

* Until 815 AM EDT.

* At 405 AM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. The expected rainfall rate is 0.5 to 1 inch in 1 
  hour. Additional rainfall amounts of 1 to 1.5 inches are possible 
  in the warned area. 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 may experience flash flooding include...
  Easton, Bethlehem, Pottstown, Emmaus, Quakertown, Hellertown, 
  Royersford, Trappe, East Greenville, Alpha, Ferndale, and 
  Schwenksville.

This includes the following highways...
	Interstate 78 in Pennsylvania between mile markers 62 and 64...and
	between mile markers 66 and 74.
	Interstate 78 in New Jersey between mile markers 0 and 8.
	Northeast Extension between mile markers 35 and 51.

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 4028 7572 4049 7557 4058 7540 4065 7526
      4074 7497 4069 7501 4013 7555 4024 7568

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...0.5-1 INCH IN 1 HOUR

$$

SFJ

4 follow-up statements

909 
WGUS71 KPHI 160835
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
435 AM EDT Sun Jul 16 2023

PAC011-029-160845-
/O.CAN.KPHI.FF.W.0060.000000T0000Z-230716T1215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-Chester PA-
435 AM EDT Sun Jul 16 2023

...FLASH FLOOD WARNING IS CANCELLED FOR EAST CENTRAL BERKS AND NORTH 
CENTRAL CHESTER COUNTIES...

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

A Flood Watch remains in effect until 1200 AM EDT Monday for 
portions of northern Delaware...New Jersey...and Pennsylvania.

LAT...LON 4044 7552 4048 7555 4058 7540 4065 7526
      4074 7497 4069 7501 4020 7555 4021 7556
      4020 7556 4019 7557 4020 7558 4024 7560
      4024 7561 4023 7560 4022 7561 4023 7562

$$

NJC019-041-PAC017-077-091-095-161215-
/O.CON.KPHI.FF.W.0060.000000T0000Z-230716T1215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Warren NJ-Bucks PA-Lehigh PA-Montgomery PA-Northampton
PA-
435 AM EDT Sun Jul 16 2023

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 AM EDT THIS 
MORNING FOR NORTHWESTERN HUNTERDON, SOUTHWESTERN WARREN, 
SOUTHEASTERN LEHIGH, SOUTHEASTERN NORTHAMPTON, NORTHWESTERN BUCKS, 
AND NORTHWESTERN MONTGOMERY COUNTIES...

At 435 AM EDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain across the warned area. Between 1 
and 2.5 inches of rain have fallen. The expected rainfall rate is 1 
to 1.5 inches in 1 hour. Additional rainfall amounts of 1 to 1.5 
inches are possible in the warned area. Flash flooding is ongoing or 
expected to begin shortly.

HAZARD...Life threatening flash flooding caused by thunderstorms.

SOURCE...Radar and automated gauges.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets, and underpasses.

Some locations that may experience flash flooding include...
  Easton, Bethlehem, Pottstown, Quakertown, Hellertown, East 
  Greenville, Alpha, Bloomsbury, Riegelsville, Green Lane, Glendon, 
  and Pleasant Valley.

This includes the following highways...
	Interstate 78 in Pennsylvania between mile markers 62 and 74.
	Interstate 78 in New Jersey between mile markers 0 and 9.
	Northeast Extension between mile markers 38 and 50.

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 4044 7552 4048 7555 4058 7540 4065 7526
      4074 7497 4069 7501 4020 7555 4021 7556
      4020 7556 4019 7557 4020 7558 4024 7560
      4024 7561 4023 7560 4022 7561 4023 7562

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL RATE...1-1.5 INCHES IN 1 HOUR

$$

SFJ

294 
WGUS71 KPHI 161032
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
632 AM EDT Sun Jul 16 2023

PAC091-161042-
/O.CAN.KPHI.FF.W.0060.000000T0000Z-230716T1215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery PA-
632 AM EDT Sun Jul 16 2023

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHWESTERN MONTGOMERY 
COUNTY...

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

A Flood Watch remains in effect until 1200 AM EDT Monday for 
portions of northern Delaware...New Jersey...and Pennsylvania.

LAT...LON 4049 7549 4058 7540 4065 7526 4074 7497
      4069 7501 4044 7535 4043 7546

$$

NJC019-041-PAC017-077-095-161215-
/O.CON.KPHI.FF.W.0060.000000T0000Z-230716T1215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Warren NJ-Bucks PA-Lehigh PA-Northampton PA-
632 AM EDT Sun Jul 16 2023

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 AM EDT THIS 
MORNING FOR NORTHWESTERN HUNTERDON, SOUTHWESTERN WARREN, 
SOUTHEASTERN LEHIGH, SOUTHEASTERN NORTHAMPTON, AND NORTHWESTERN 
BUCKS COUNTIES...

At 632 AM EDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain had moved out of the warned area, 
but additional light rain is possible over the next hour. Between 1 
and 3 inches of rain have fallen. Additional rainfall amounts up to 
0.5 inches are possible in the warned area. Flash flooding is 
ongoing or expected to begin shortly.

HAZARD...Life threatening flash flooding caused by thunderstorms.

SOURCE...Radar and automated gauges.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets, and underpasses.

Some locations that may experience flash flooding include...
  Easton, Bethlehem, Quakertown, Hellertown, Alpha, Bloomsbury, 
  Riegelsville, Glendon, Pleasant Valley, Springtown, Phillipsburg, 
  and Coopersburg.

This includes the following highways...
	Interstate 78 in Pennsylvania between mile markers 63 and 74.
	Interstate 78 in New Jersey between mile markers 0 and 8.
	Northeast Extension between mile markers 44 and 49.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4049 7549 4058 7540 4065 7526 4074 7497
      4069 7501 4044 7535 4043 7546

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

SFJ

868 
WGUS51 KPHI 161211
FFWPHI
NJC019-041-PAC017-077-095-161345-
/O.EXT.KPHI.FF.W.0060.000000T0000Z-230716T1345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
811 AM EDT Sun Jul 16 2023

The National Weather Service in Mount Holly has extended the

* Flash Flood Warning for...
  Northwestern Hunterdon County in northwestern New Jersey...
  Southwestern Warren County in northwestern New Jersey...
  Southeastern Lehigh County in eastern Pennsylvania...
  Southeastern Northampton County in eastern Pennsylvania...
  Northwestern Bucks County in southeastern Pennsylvania...

* Until 945 AM EDT.

* At 811 AM EDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  1 and 3 inches of rain have fallen. Additional rainfall amounts up 
  to 0.5 inches are possible in the warned area. Flash flooding is 
  ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar and automated gauges.

  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 may experience flash flooding include...
  Easton, Bethlehem, Quakertown, Hellertown, Alpha, Bloomsbury, 
  Riegelsville, Glendon, Pleasant Valley, Springtown, Phillipsburg, 
  and Coopersburg.

This includes the following highways...
	Interstate 78 in Pennsylvania between mile markers 63 and 74.
	Interstate 78 in New Jersey between mile markers 0 and 8.
	Northeast Extension between mile markers 44 and 49.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 4049 7549 4058 7540 4065 7526 4074 7497
      4069 7501 4044 7535 4043 7546

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

MJL

891 
WGUS71 KPHI 161336
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
936 AM EDT Sun Jul 16 2023

NJC019-041-PAC017-077-095-161346-
/O.CAN.KPHI.FF.W.0060.000000T0000Z-230716T1345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Warren NJ-Bucks PA-Lehigh PA-Northampton PA-
936 AM EDT Sun Jul 16 2023

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHWESTERN HUNTERDON, 
SOUTHWESTERN WARREN, SOUTHEASTERN LEHIGH, SOUTHEASTERN NORTHAMPTON, 
AND NORTHWESTERN BUCKS COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat.

A Flood Watch remains in effect until 1200 AM EDT Monday for 
portions of northern Delaware...New Jersey...and Pennsylvania.

LAT...LON 4049 7549 4058 7540 4065 7526 4074 7497
      4069 7501 4044 7535 4043 7546

$$

MJL

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 16, 2:22 AM EDT	Special Marine Warning	PHI		53 min
Jul 16, 2:47 AM EDT	Special Weather Statement	PHI	Gloucester, Salem	28 min
Jul 16, 3:08 AM EDT	Special Marine Warning	PHI		42 min
Jul 16, 3:40 AM EDT	Flash Flood Warning	PHI	Sussex, Warren	7 hr
Jul 16, 4:14 AM EDT	Special Weather Statement	PHI	Hunterdon	31 min
Jul 16, 4:38 AM EDT	Tornado Warning	PHI	Hunterdon, Somerset	37 min
Jul 16, 4:50 AM EDT	Special Weather Statement	PHI	Burlington, Ocean	25 min
Jul 16, 5:07 AM EDT	Tornado Warning	PHI	Hunterdon, Morris, Somerset	38 min
Jul 16, 5:13 AM EDT	Flash Flood Warning	PHI	Sussex, Warren	4 hr
Jul 16, 5:16 AM EDT	Special Weather Statement	PHI	Ocean	29 min
Jul 16, 5:26 AM EDT	Flash Flood Warning	PHI	Hunterdon, Morris, Sussex, Warren	4 hr
Jul 16, 5:31 AM EDT	Tornado Warning	PHI	Morris, Somerset, Sussex	29 min
Jul 16, 5:44 AM EDT	Special Marine Warning	PHI		61 min
Jul 16, 5:45 AM EDT	Special Weather Statement	PHI	Monmouth	30 min
Jul 16, 5:58 AM EDT	Tornado Warning	PHI	Morris	32 min
Jul 16, 7:52 AM EDT	Special Marine Warning	PHI		53 min
Jul 16, 8:40 AM EDT	Special Marine Warning	PHI		47 min
Jul 16, 10:54 AM EDT	Areal Flood Warning	PHI	Warren	5 hr
Jul 16, 11:08 AM EDT	Flash Flood Warning	PHI	Gloucester, Salem	3 hr
Jul 16, 11:36 AM EDT	Flash Flood Warning	PHI	Middlesex, Somerset	3 hr
Jul 16, 12:22 PM EDT	Areal Flood Advisory	PHI	Mercer	3 hr
Jul 16, 12:26 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden	3 hr
Jul 16, 1:47 PM EDT	Areal Flood Advisory	PHI	Gloucester, Salem	80 min
Jul 16, 1:50 PM EDT	Special Marine Warning	PHI		85 min
Jul 16, 2:20 PM EDT	Areal Flood Advisory	PHI	Middlesex, Somerset	72 min
Jul 16, 2:42 PM EDT	Special Weather Statement	PHI	Cape May	48 min
Jul 16, 3:09 PM EDT	Special Marine Warning	PHI		51 min
Jul 16, 6:17 PM EDT	Areal Flood Warning	PHI	Warren	10 hr
Jul 16, 6:19 PM EDT	Areal Flood Warning	PHI	Warren	10 hr
Jul 15, 8:37 PM EDT	Areal Flood Advisory	PHI	Carbon	19 min
Jul 15, 8:44 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	30 min
Jul 15, 8:56 PM EDT	Flash Flood Warning	PHI	Carbon	95 min
Jul 16, 12:50 AM EDT	Special Weather Statement	PHI	Berks	25 min
Jul 16, 1:41 AM EDT	Special Weather Statement	PHI	Carbon, Lehigh	34 min
Jul 16, 2:12 AM EDT	Special Weather Statement	PHI	Carbon, Lehigh, Monroe	33 min
Jul 16, 2:43 AM EDT	Flash Flood Warning	PHI	Carbon, Lehigh, Monroe, Northampton	4 hr
Jul 16, 9:12 AM EDT	Flash Flood Warning	PHI	Chester	2 hr
Jul 16, 9:40 AM EDT	Flash Flood Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	3 hr
Jul 16, 9:53 AM EDT	Tornado Warning	PHI	Montgomery, Philadelphia	37 min
Jul 16, 6:44 PM EDT	Areal Flood Advisory	PHI	Bucks	90 min

Nearby

Flash Flood Warnings in Pennsylvania, 2023 Flash Flood Warnings in New Jersey, 2023 Every flash flood warning in 2023

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.