Alert archive / Pennsylvania / Areal Flood Warnings in 2021

Areal Flood Warning 48, NWS Philadelphia/Mount Holly

September 9, 2021Northampton County, Pennsylvania; Warren County, New Jersey

NWS Philadelphia/Mount Holly issued this areal flood warning at Sep 9, 2021, 4:28 AM EDT for Northampton County, Pennsylvania; Warren County, New Jersey. It was in force for 4 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: Sep 9, 2021, 4:28 AM EDT (08:28 UTC)
Expired: Sep 9, 2021, 8:30 AM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Warren County, NJ, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 112 km from the middle of the area, began a volume at 08:28 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, 8.5 hours before the alert went out and 188 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: 619 J/kg
Mixed-layer CIN: -36 J/kg
Mixed-layer LCL: 807 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 211 m²/s²
0-3 km storm-relative helicity: 225 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 3.4

Open this sounding in Storm Lab

The text

As transmitted.

934 
WGUS41 KPHI 090828
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
428 AM EDT Thu Sep 9 2021

NJC041-PAC095-091230-
/O.NEW.KPHI.FA.W.0048.210909T0828Z-210909T1230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Warren NJ-Northampton PA-
428 AM EDT Thu Sep 9 2021

The National Weather Service in Mount Holly has issued a

* Flood Warning for...
  Warren County in northwestern New Jersey...
  Eastern Northampton County in eastern Pennsylvania...

* Until 830 AM EDT.

* At 428 AM EDT, local law enforcement reported flooding in the 
  warned area. Flooding is already occurring. Between 2 and 4 inches 
  of rain fell with thunderstorms Wednesday evening.

* Some locations that may experience flooding include...
  Easton, Bethlehem, Forks, Hackettstown, Wilson, Washington, 
  Blairstown, Nazareth, Bangor, Pen Argyl, Wind Gap, and Belvidere.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4060 7522 4064 7540 4070 7528 4083 7539
      4086 7529 4090 7523 4093 7521 4096 7513
      4099 7513 4103 7504 4109 7497 4091 7477
      4088 7481 4086 7480 4084 7482 4078 7490
      4071 7497 4063 7515 4059 7518 4061 7520

$$

SFJ

1 follow-up statement

715 
WGUS81 KPHI 091227
FLSPHI

Flood Statement
National Weather Service Mount Holly NJ
827 AM EDT Thu Sep 9 2021

NJC041-PAC095-091237-
/O.EXP.KPHI.FA.W.0048.000000T0000Z-210909T1230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Warren NJ-Northampton PA-
827 AM EDT Thu Sep 9 2021

...FLOOD WARNING WILL EXPIRE AT 830 AM EDT THIS MORNING FOR WARREN 
AND EASTERN NORTHAMPTON COUNTIES...

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

LAT...LON 4060 7522 4064 7540 4070 7528 4083 7539
      4086 7529 4090 7523 4093 7521 4096 7513
      4099 7513 4103 7504 4109 7497 4091 7477
      4088 7481 4086 7480 4084 7482 4078 7490
      4071 7497 4063 7515 4059 7518 4061 7520

$$

Robertson

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 8, 8:47 PM EDT	Special Weather Statement	PHI	Northampton	28 min
Sep 8, 9:12 PM EDT	Special Weather Statement	PHI	Lehigh	48 min
Sep 8, 9:16 PM EDT	Areal Flood Advisory	PHI	Lehigh, Northampton	3 hr
Sep 8, 9:16 PM EDT	Special Weather Statement	PHI	Northampton	29 min
Sep 8, 9:38 PM EDT	Special Weather Statement	PHI	Berks	52 min
Sep 8, 9:46 PM EDT	Special Weather Statement	PHI	Lehigh, Northampton	44 min
Sep 8, 9:48 PM EDT	Flash Flood Warning	PHI	Lehigh, Northampton	7 hr
Sep 8, 9:59 PM EDT	Areal Flood Advisory	PHI	Berks	3 hr
Sep 8, 10:11 PM EDT	Severe Thunderstorm Warning	PHI	Berks	49 min
Sep 8, 10:23 PM EDT	Tornado Warning	PHI	Berks	22 min
Sep 8, 10:27 PM EDT	Special Weather Statement	PHI	Northampton	33 min
Sep 8, 10:42 PM EDT	Flash Flood Warning	PHI	Northampton	6 hr
Sep 8, 10:47 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	3 hr
Sep 8, 10:47 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh, Montgomery, Northampton	58 min
Sep 8, 10:56 PM EDT	Special Weather Statement	PHI	Northampton	34 min
Sep 8, 11:27 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Northampton	48 min
Sep 8, 11:35 PM EDT	Special Weather Statement	PHI	Chester, Delaware, Montgomery	40 min
Sep 9, 12:08 AM EDT	Special Weather Statement	PHI	Bucks, Delaware, Montgomery, Philadelphia	37 min
Sep 9, 4:26 AM EDT	Areal Flood Warning	PHI	Lehigh, Northampton	3 hr
Sep 8, 9:43 PM EDT	Special Weather Statement	PHI	Sussex, Warren	47 min
Sep 8, 11:30 PM EDT	Areal Flood Advisory	PHI	Morris, Sussex	4 hr
Sep 9, 12:07 AM EDT	Special Weather Statement	PHI	Hunterdon, Somerset, Warren	23 min
Sep 9, 12:18 AM EDT	Special Marine Warning	PHI		57 min
Sep 9, 12:30 AM EDT	Special Weather Statement	PHI	Morris	30 min
Sep 9, 12:41 AM EDT	Special Marine Warning	PHI		52 min
Sep 9, 2:17 AM EDT	Special Weather Statement	PHI	Ocean	28 min
Sep 9, 2:46 AM EDT	Special Weather Statement	PHI	Atlantic	29 min
Sep 9, 3:14 AM EDT	Special Weather Statement	PHI	Atlantic	31 min
Sep 9, 3:30 AM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Cape May, Cumberland	112 min

Nearby

Areal Flood Warnings in Pennsylvania, 2021 Areal Flood Warnings in New Jersey, 2021 Every 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.