Alert archive / Pennsylvania / Flash Flood Warnings in 2023

Flash Flood Warning 42, NWS Philadelphia/Mount Holly

July 9, 2023Berks County, Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 9, 2023, 2:46 PM EDT for Berks County, Lehigh County, Northampton County, Pennsylvania. It was in force for 6 hr. 3 reports 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: Jul 9, 2023, 2:46 PM EDT (18:46 UTC)
Expired: Jul 9, 2023, 8:45 PM EDT
In force: 6 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Berks County, PA, Lehigh County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 138 km from the middle of the area, began a volume at 18:49 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

Time	Report	Where	Remark
Jul 9, 3:40 PM EDT	FLOOD	Kutztown, PA	Trained Spotter reports street flooding on Willow Street in Kutztown. Road is still passable at this time.
Jul 9, 6:25 PM EDT	FLOOD	1 Wsw Allentown, PA	Report of street flooding along the 1900 block of Union Street in Allentown.
Jul 9, 6:25 PM EDT	FLOOD	3 Wsw Allentown, PA	Report of street flooding on Cedar Crest Blvd and Hamilton Blvd in Allentown.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.8 hours before the alert went out and 234 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: 952 J/kg
Mixed-layer CIN: -58 J/kg
Mixed-layer LCL: 686 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 12 m²/s²
0-3 km storm-relative helicity: 37 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

107 
WGUS51 KPHI 091846
FFWPHI
PAC011-077-095-100045-
/O.NEW.KPHI.FF.W.0042.230709T1846Z-230710T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
246 PM EDT Sun Jul 9 2023

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northeastern Berks County in eastern Pennsylvania...
  Lehigh County in eastern Pennsylvania...
  West Central Northampton County in eastern Pennsylvania...

* Until 845 PM EDT.

* At 246 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Additional rainfall amounts of 1 to 3 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...
  Allentown, Northampton, Kutztown, Hamburg, Slatington, Walnutport, 
  Topton, Lyons, Lenhartsville, Claussville, New Tripoli, and Jordan 
  Valley.

This includes the following highways...
	Interstate 78 in Pennsylvania between mile markers 32 and 57.
	Northeast Extension between mile markers 54 and 68.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4069 7584 4076 7571 4072 7546 4057 7547
      4047 7576 4057 7601 4064 7599

FLASH FLOOD...RADAR INDICATED

$$

Hoeflich

1 follow-up statement

754 
WGUS71 KPHI 100035
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
835 PM EDT Sun Jul 9 2023

PAC011-077-095-100045-
/O.EXP.KPHI.FF.W.0042.000000T0000Z-230710T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-Lehigh PA-Northampton PA-
835 PM EDT Sun Jul 9 2023

...FLASH FLOOD WARNING WILL EXPIRE AT 845 PM EDT THIS EVENING FOR 
NORTHEASTERN BERKS, LEHIGH, AND WEST CENTRAL NORTHAMPTON COUNTIES...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat.

A Flood Watch remains in effect until 1200 AM EDT for portions of 
east central Pennsylvania...northeast Pennsylvania...and southeast 
Pennsylvania.

LAT...LON 4069 7584 4076 7571 4072 7546 4057 7547
      4047 7576 4057 7601 4064 7599

$$

Hoeflich

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 9, 11:00 AM EDT	Special Weather Statement	PHI	Carbon	30 min
Jul 9, 11:33 AM EDT	Flash Flood Warning	PHI	Chester, Delaware, Montgomery	8 hr
Jul 9, 11:47 AM EDT	Special Weather Statement	PHI	Monroe	43 min
Jul 9, 11:49 AM EDT	Special Weather Statement	PHI	Montgomery	41 min
Jul 9, 11:54 AM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Lehigh, Montgomery	33 min
Jul 9, 12:14 PM EDT	Special Weather Statement	PHI	Bucks	46 min
Jul 9, 12:15 PM EDT	Special Weather Statement	PHI	Monroe	30 min
Jul 9, 12:22 PM EDT	Special Weather Statement	PHI	Lebanon	38 min
Jul 9, 12:27 PM EDT	Flash Flood Warning	PHI	Berks, Bucks, Lehigh, Montgomery	8 hr
Jul 9, 12:37 PM EDT	Areal Flood Advisory	PHI	Bucks, Lehigh, Northampton	2 hr
Jul 9, 12:43 PM EDT	Areal Flood Advisory	PHI	Berks	33 min
Jul 9, 12:51 PM EDT	Special Weather Statement	PHI	Northampton	24 min
Jul 9, 12:57 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	6 hr
Jul 9, 1:02 PM EDT	Flash Flood Warning	PHI	Bucks, Lehigh, Northampton	8 hr
Jul 9, 1:16 PM EDT	Flash Flood Warning	PHI	Berks	6 hr
Jul 9, 1:17 PM EDT	Special Weather Statement	PHI	Berks	28 min
Jul 9, 1:32 PM EDT	Areal Flood Advisory	PHI	Carbon, Lehigh, Monroe, Northampton	4 hr
Jul 9, 2:16 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh	30 min
Jul 9, 2:41 PM EDT	Flash Flood Warning	PHI	Berks	4 hr
Jul 9, 3:01 PM EDT	Special Weather Statement	PHI	Berks	29 min
Jul 9, 3:03 PM EDT	Special Weather Statement	PHI	Chester	27 min
Jul 9, 3:15 PM EDT	Severe Thunderstorm Warning	PHI	Berks	30 min
Jul 9, 3:20 PM EDT	Special Weather Statement	PHI	Berks	25 min
Jul 9, 3:27 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester	33 min
Jul 9, 3:41 PM EDT	Special Weather Statement	PHI	Berks	34 min
Jul 9, 3:51 PM EDT	Flash Flood Warning Considerable damage threat	PHI	Berks, Chester, Lehigh, Montgomery	6 hr
Jul 9, 3:59 PM EDT	Special Weather Statement	PHI	Chester	31 min
Jul 9, 4:03 PM EDT	Severe Thunderstorm Warning	PHI	Montgomery	27 min
Jul 9, 4:19 PM EDT	Special Weather Statement	PHI	Chester	26 min
Jul 9, 4:31 PM EDT	Flash Flood Warning	PHI	Chester, Montgomery	4 hr
Jul 9, 5:10 PM EDT	Severe Thunderstorm Warning	PHI	Delaware	50 min
Jul 9, 5:12 PM EDT	Flash Flood Warning	PHI	Bucks, Montgomery	5 hr
Jul 9, 5:15 PM EDT	Special Weather Statement	PHI	Bucks, Delaware, Philadelphia	30 min
Jul 9, 5:31 PM EDT	Flash Flood Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	4 hr
Jul 9, 5:35 PM EDT	Severe Thunderstorm Warning	PHI	Philadelphia	25 min
Jul 9, 5:59 PM EDT	Flash Flood Warning	PHI	Bucks, Montgomery	4 hr
Jul 9, 6:05 PM EDT	Special Weather Statement	PHI	Bucks	25 min
Jul 9, 7:04 PM EDT	Areal Flood Warning	PHI	Berks	9 hr
Jul 9, 7:11 PM EDT	Areal Flood Advisory	PHI	Bucks	3 hr
Jul 9, 7:27 PM EDT	River Flood Warning	PHI	Chester	4 hr

Nearby

Flash Flood Warnings in Pennsylvania, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.