Alert archive / Pennsylvania / Flash Flood Warnings in 2018

Flash Flood Warning 112, NWS Philadelphia/Mount Holly

November 2, 20186 counties in Pennsylvania; Hunterdon County, Warren County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Nov 2, 2018, 10:53 PM EDT for 6 counties in Pennsylvania; Hunterdon County, Warren County, New Jersey. It was in force for 4 hr. 12 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: Nov 2, 2018, 10:53 PM EDT (02:53 UTC)
Expired: Nov 3, 2018, 2:45 AM EDT
In force: 4 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), 119 km from the middle of the area, began a volume at 02:52 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
Nov 2, 11:04 PM EDT	FLASH FLOOD	Pottstown, PA	WATER RESCUE REPORTED IN POTTSTOWN AT HIGH ST. AND ARMAND HAMMER BLVD.
Nov 2, 11:14 PM EDT	FLASH FLOOD	Upper Pottsgrove Twp, PA	WATER RESCUE REPORTED ON WILLOW ST.
Nov 2, 11:22 PM EDT	FLASH FLOOD	1 S Amity Twp, PA	TWO BUSINESSES SUSTAINED FLOODING DAMAGE NEAR U.S. HIGHWAY 422 IN AMITY TWP. THE HIGHWAY WAS CLOSED FOR SEVERAL HOURS.
Nov 2, 11:29 PM EDT	FLASH FLOOD	South Pottstown, PA	WATER RESCUE AT INTERSECTION OF WASHINGTON STREET AND BRINGHURST ALLEY.
Nov 2, 11:39 PM EDT	FLASH FLOOD	2 Ssw Allentown, PA	INTERSTATE 78 CLOSED BETWEEN EXITS 57 AND 60 FROM FLASH FLOODING.
Nov 3, 12:15 AM EDT	FLASH FLOOD	Bethlehem Twp, PA	MULTIPLE WATER RESCUES REPORTED IN PALMER TWP, BETHLEHEM TWP, UPPER SAUCON TWP, AND EASTON CITY.
Nov 3, 12:28 AM EDT	FLASH FLOOD	Washington Twp, PA	WATER RESCUE REPORTED ON DALE ROAD.
Nov 3, 12:30 AM EDT	FLASH FLOOD	1 Se Fountain Hill, PA	LANDSLIDE ON SEIDERSVILLE ROAD NEAR FIRE LANE IN LOWER SAUCON TWP. CONSIDERABLE FLOODING IN MUCH OF THE TOWNSHIP, EXACERBATED BY CLOGGED DRAINS FROM FALLEN LEAVES. TIME ESTIMATED BASED ON SURROUNDING REPORTS OF FLOODING.
Nov 3, 12:33 AM EDT	FLASH FLOOD	Emmaus, PA	PORTIONS OF THE LOWER LEVEL OF EMMAUS HIGH SCHOOL WAS FLOODED.
Nov 3, 1:00 AM EDT	FLASH FLOOD	2 Ssw Milford Twp, PA	SEVERAL ROADS CLOSED FROM FLASH FLOODING IN MILFORD TWP...INCLUDING BROAD STREET, MAIN STREET, TRUMBAUERSVILLE ROAD, AND SWAMP CREEK ROAD BETWEEN FELS ROAD AND NURSERY ROAD. TIME ESTIMATED.
Nov 3, 1:03 AM EDT	FLASH FLOOD	1 Nw East Greenville, PA	WATER RESCUE AT INTERSECTION OF MILL HILL ROAD AND GRAVEL PIKE.
Nov 3, 1:14 AM EDT	HEAVY RAIN 2.12	Gilbertsville, PA

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 00:00Z, 2.9 hours before the alert went out and 194 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: 34 J/kg
Mixed-layer CIN: -22 J/kg
Mixed-layer LCL: 557 m above ground
0-6 km bulk shear: 70 kt
0-1 km storm-relative helicity: 381 m²/s²
0-3 km storm-relative helicity: 603 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

494 
WGUS51 KPHI 030253
FFWPHI
NJC019-041-PAC011-017-029-077-091-095-030645-
/O.NEW.KPHI.FF.W.0112.181103T0253Z-181103T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1053 PM EDT FRI NOV 2 2018

The National Weather Service in Mount Holly NJ has issued a

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

* Until 245 AM EDT.

* At 1050 PM EDT, Doppler radar indicated heavy rain across the 
  warned area. Up to two inches of rain have already fallen within 
  the last hour in addition to heavy rainfall from earlier. Flash 
  flooding is expected to begin shortly in the areas of heaviest 
  rain.

* Some locations that could experience flooding include...
  Allentown, Easton, Bethlehem, Pottstown, Phoenixville, Forks,
  Coatesville, Emmaus, Northampton, Quakertown, Perkasie, Wilson,
  Downingtown, Souderton, Washington, Hellertown, Nazareth, Bangor,
  Birdsboro and Collegeville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 3976 7606 3983 7604 3987 7599 3995 7600
      4004 7593 4011 7594 4014 7588 4021 7599
      4084 7536 4086 7529 4091 7524 4079 7489
      3972 7587 3972 7612

$$

Robertson

2 follow-up statements

466 
WGUS71 KPHI 030402
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1202 AM EDT SAT NOV 3 2018

NJC019-041-PAC011-017-029-077-091-095-030645-
/O.CON.KPHI.FF.W.0112.000000T0000Z-181103T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Warren NJ-Berks PA-Montgomery PA-Lehigh PA-Bucks PA-
Chester PA-Northampton PA-
1202 AM EDT SAT NOV 3 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 245 AM EDT FOR
NORTHWESTERN HUNTERDON...SOUTHWESTERN WARREN...SOUTHEASTERN BERKS...
NORTHWESTERN MONTGOMERY...SOUTHEASTERN LEHIGH...NORTHWESTERN BUCKS...
CHESTER AND NORTHAMPTON COUNTIES...

At 1159 PM EDT, Doppler radar indicated moderate to heavy rain 
continuing across the warned area. Up to three to four inches of 
rain have already fallen across the area. Flash flooding is 
occurring with water rescues already being performed. Additionally, 
Monocacy River near Bethlehem is flooding as well as Perkiomen Creek 
near East Greenville. Many other creeks and streams are rising.

Some locations that could experience flooding include...
Allentown, Easton, Bethlehem, Pottstown, Phoenixville, Forks,
Coatesville, Emmaus, Northampton, Quakertown, Perkasie, Wilson,
Downingtown, Souderton, Washington, Hellertown, Nazareth, Bangor,
Birdsboro and Collegeville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Stay away or be swept away. River banks and culverts can become
unstable and unsafe.

In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.

&&

LAT...LON 3976 7606 3983 7604 3987 7599 3995 7600
      4004 7593 4011 7594 4014 7588 4021 7599
      4084 7536 4086 7529 4091 7524 4079 7489
      3972 7587 3972 7612

$$

Robertson

783 
WGUS71 KPHI 030645
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
245 AM EDT SAT NOV 3 2018

NJC019-041-PAC011-017-029-077-091-095-030653-
/O.EXP.KPHI.FF.W.0112.000000T0000Z-181103T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Warren NJ-Berks PA-Montgomery PA-Lehigh PA-Bucks PA-
Chester PA-Northampton PA-
245 AM EDT SAT NOV 3 2018

...THE FLASH FLOOD WARNING FOR NORTHWESTERN HUNTERDON...SOUTHWESTERN
WARREN...SOUTHEASTERN BERKS...NORTHWESTERN MONTGOMERY...SOUTHEASTERN
LEHIGH...NORTHWESTERN BUCKS...CHESTER AND NORTHAMPTON COUNTIES WILL
EXPIRE AT 245 AM EDT...

The heavy rain has ended. However, numerous rivers, creeks, and 
streams remain above their flood stages. An area flood warning 
remains in effect for these rivers. 

LAT...LON 3976 7606 3983 7604 3987 7599 3995 7600
      4004 7593 4011 7594 4014 7588 4021 7599
      4084 7536 4086 7529 4091 7524 4079 7489
      3972 7587 3972 7612

$$

Robertson

The office that day

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

Issued	Product	Office	Counties	Lasted
Nov 2, 8:22 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh, Northampton	4 hr
Nov 2, 9:28 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Chester, Lehigh, Montgomery, Northampton	4 hr
Nov 2, 9:48 PM EDT	Special Weather Statement	PHI	Berks, Chester	27 min
Nov 2, 10:09 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery	51 min
Nov 2, 10:32 PM EDT	Tornado Warning	PHI	Berks, Chester, Montgomery	28 min
Nov 2, 10:36 PM EDT	Special Weather Statement	PHI	Northampton	24 min
Nov 2, 10:45 PM EDT	Areal Flood Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery, Northampton	13 hr
Nov 2, 10:47 PM EDT	Tornado Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery, Northampton	43 min
Nov 2, 10:53 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 1 more	67 min
Nov 2, 11:23 PM EDT	Tornado Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	24 min
Nov 2, 11:25 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	4 hr
Nov 2, 11:49 PM EDT	Tornado Warning	PHI	Bucks	26 min
Nov 2, 11:53 PM EDT	Areal Flood Advisory	PHI	Bucks	4 hr
Nov 2, 11:53 PM EDT	Special Weather Statement	PHI	Delaware, Philadelphia	37 min
Nov 3, 12:20 AM EDT	Areal Flood Advisory	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	4 hr
Nov 3, 1:03 AM EDT	River Flood Warning	PHI	Lehigh	5 hr
Nov 3, 1:29 AM EDT	Areal Flood Advisory	PHI	Monroe, Northampton	4 hr
Nov 3, 1:41 AM EDT	Areal Flood Advisory	PHI	Bucks	4 hr
Nov 3, 2:03 AM EDT	River Flood Warning	PHI	Chester	6 hr
Nov 3, 2:34 AM EDT	Areal Flood Warning	PHI	Bucks, Northampton	15 hr
Nov 3, 2:40 AM EDT	River Flood Warning	PHI	Montgomery	10 hr
Nov 3, 2:40 AM EDT	River Flood Warning	PHI	Chester, Montgomery, Philadelphia	15 hr
Nov 3, 3:21 AM EDT	Areal Flood Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	4 hr
Nov 3, 5:00 AM EDT	River Flood Warning	PHI	Chester, Delaware	6 hr
Nov 3, 7:01 AM EDT	Areal Flood Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	5 hr
Nov 3, 11:44 AM EDT	Areal Flood Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery, Northampton	8 hr
Nov 3, 5:19 PM EDT	Areal Flood Warning	PHI	Northampton	22 hr
Nov 2, 9:26 PM EDT	Areal Flood Advisory	PHI	Morris, Sussex, Warren	4 hr
Nov 2, 11:13 PM EDT	Special Marine Warning	PHI		62 min
Nov 2, 11:43 PM EDT	Special Weather Statement	PHI	Cumberland	32 min
Nov 3, 12:09 AM EDT	Special Marine Warning	PHI		66 min
Nov 3, 12:13 AM EDT	Special Weather Statement	PHI	Camden, Gloucester, Salem	62 min
Nov 3, 12:18 AM EDT	Special Weather Statement	PHI	Hunterdon, Morris, Somerset, Warren	27 min
Nov 3, 1:00 AM EDT	Special Weather Statement	PHI	Camden, Hunterdon, Mercer, Middlesex, Morris, Somerset	60 min
Nov 3, 1:06 AM EDT	Special Marine Warning	PHI		54 min
Nov 3, 1:29 AM EDT	Special Marine Warning	PHI		91 min
Nov 3, 2:00 AM EDT	River Flood Warning	PHI	Morris, Passaic	37 hr
Nov 3, 3:15 AM EDT	River Flood Warning	PHI	Hunterdon, Somerset	4 hr
Nov 3, 5:54 PM EDT	Small Craft Advisory	PHI		12 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2018 Flash Flood Warnings in New Jersey, 2018 Every flash flood warning in 2018

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.