Alert archive / Pennsylvania / Flash Flood Warnings in 2022

Flash Flood Warning 20, NWS Philadelphia/Mount Holly

October 13, 20224 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Oct 13, 2022, 7:21 PM EDT for 4 counties in Pennsylvania. 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
Oct 13, 2022, 7:21 PM EDT (23:21 UTC)
Expired
Oct 13, 2022, 11:30 PM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Bucks County, PA, Chester County, PA, Lehigh County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 110 km from the middle of the area, began a volume at 23:24 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.4 hours before the alert went out and 214 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, Washington/Dulle, VA at 12:00Z on 2022-10-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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, Washington/Dulle, VA at 12:00Z on 2022-10-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 272 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
502 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
272 m²/s²
0-3 km storm-relative helicity
283 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

802 
WGUS51 KPHI 132321
FFWPHI
PAC017-029-077-091-140330-
/O.NEW.KPHI.FF.W.0020.221013T2321Z-221014T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
721 PM EDT Thu Oct 13 2022

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Southern Lehigh County in eastern Pennsylvania...
  Western Bucks County in southeastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...
  Northwestern Montgomery County in southeastern Pennsylvania...

* Until 1130 PM EDT.

* At 721 PM EDT, Doppler radar and automated rain gauges indicated 
  heavy rain falling and flooding occurring at Perkiomen Creek at 
  East Greenville. Between 1 and 2 inches of rain have fallen. 
  Additional rainfall amounts of 0.5 to 1 inch are possible in the 
  warned area. Flash flooding is already occurring.

  HAZARD...Flash flooding caused by heavy rain.

  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...
  Pottstown, Phoenixville, Royersford, Trappe, East Greenville, 
  Schwenksville, Green Lane, Gilbertsville, Spring Mount, 
  Cedarville, Pughtown, and Geryville.

This includes the following highways...
	Pennsylvania Turnpike between mile markers 317 and 318.
	Northeast Extension between mile markers 37 and 44.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4024 7570 4026 7568 4027 7567 4028 7567
      4033 7563 4036 7560 4038 7559 4040 7557
      4042 7555 4049 7549 4039 7534 4006 7557
      4016 7577 4023 7571

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

SFJ
2 follow-up statements
521 
WGUS71 KPHI 140021
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
821 PM EDT Thu Oct 13 2022

PAC017-029-077-091-140330-
/O.CON.KPHI.FF.W.0020.000000T0000Z-221014T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-Chester PA-Lehigh PA-Montgomery PA-
821 PM EDT Thu Oct 13 2022

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1130 PM EDT THIS 
EVENING FOR SOUTHERN LEHIGH, WESTERN BUCKS, NORTHEASTERN CHESTER, 
AND NORTHWESTERN MONTGOMERY COUNTIES...

At 821 PM EDT, gauge reports indicated that flash flooding was 
occurring on the Perkiomen Creek at East Greenville. Between 1.5 and 
3 inches of rain have fallen. Although the heaviest rain has left 
the warned area, it will take time for runoff to subside. 
Additionally, light rain with  amounts up to 0.5 inches are possible 
over the next hour. Flash flooding is already occurring.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Gauges reported.

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...
  Pottstown, Phoenixville, Royersford, Trappe, East Greenville, 
  Schwenksville, Green Lane, Gilbertsville, Spring Mount, 
  Cedarville, Pughtown, and Geryville.

This includes the following highways...
	Pennsylvania Turnpike near mile marker 317.
	Northeast Extension between mile markers 37 and 45.

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 4024 7570 4026 7568 4027 7567 4028 7567
      4033 7563 4036 7560 4038 7559 4040 7557
      4042 7555 4049 7549 4039 7534 4006 7557
      4016 7577 4023 7571

FLASH FLOOD...GAUGE INDICATED

$$

SFJ
240 
WGUS71 KPHI 140331
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1131 PM EDT Thu Oct 13 2022

PAC017-029-077-091-140341-
/O.EXP.KPHI.FF.W.0020.000000T0000Z-221014T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-Chester PA-Lehigh PA-Montgomery PA-
1131 PM EDT Thu Oct 13 2022

...FLASH FLOOD WARNING HAS EXPIRED FOR SOUTHERN LEHIGH, WESTERN 
BUCKS, NORTHEASTERN CHESTER, AND NORTHWESTERN MONTGOMERY COUNTIES...

Flood waters have receded. Flooding is no longer expected to pose a 
threat.

LAT...LON 4024 7570 4026 7568 4027 7567 4028 7567
      4033 7563 4036 7560 4038 7559 4040 7557
      4042 7555 4049 7549 4039 7534 4006 7557
      4016 7577 4023 7571

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 13, 5:18 PM EDTAreal Flood AdvisoryPHIChester38 min
Oct 13, 5:55 PM EDTSpecial Weather StatementPHILehigh35 min
Oct 13, 6:25 PM EDTSpecial Weather StatementPHINorthampton35 min
Oct 13, 7:34 PM EDTAreal Flood AdvisoryPHIBucks, Lehigh, Northampton3 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2022Every flash flood warning in 2022

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.