Alert archive / Pennsylvania / Flash Flood Warnings in 2021

Flash Flood Warning 60, NWS Philadelphia/Mount Holly

August 28, 2021Berks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 28, 2021, 4:06 AM EDT for Berks County, Pennsylvania. It was in force for 3 hr. 8 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
Aug 28, 2021, 4:06 AM EDT (08:06 UTC)
Expired
Aug 28, 2021, 7:00 AM EDT
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

County Berks County, PA

The radar

The Philadelphia radar (KDIX), 150 km from the middle of the area, began a volume at 08:05 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

TimeReportWhereRemark
Aug 28, 4:09 AM EDTFLOOD1 Ese Leesport, PAMPING REPORT OF FLOODING ON ONTELAUNEE DRIVE.
Aug 28, 4:10 AM EDTFLASH FLOOD1 S Muhlenberg Twp, PAMULTIPLE VEHICLES STUCK IN WATER WITH WATER RESCUES REQUIRED NEAR THE INTERSECTION OF ROUTE 12 AND STATE HIGHWAY 61. TIME BASED ON DISPATCH REPORT.
Aug 28, 4:20 AM EDTFLASH FLOODSouth Heidelberg Twp, PAFLASH FLOODING ON FRITZTOWN ROAD RESULTING IN CLOSURES. TIME BASED ON DISPATCH REPORT.
Aug 28, 4:25 AM EDTFLASH FLOOD1 Ene South Heidelberg, PACHAPEL HILL ROAD FLOODED AND IMPASSABLE. TIME BASED ON DISPATCH REPORT.
Aug 28, 4:30 AM EDTFLASH FLOODTemple, PAMOUNT LAUREL ROAD CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT.
Aug 28, 4:32 AM EDTFLASH FLOOD2 E South Heidelberg Tw, PAGELSINGER ROAD AND WHEATFIELD ROAD CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT.
Aug 28, 5:00 AM EDTFLASH FLOOD1 Ene South Heidelberg, PAPORTIONS OF FRITZTOWN ROAD WASHED OUT FROM FLASH FLOODING. TIME BASED ON DISPATCH REPORT.
Aug 28, 5:30 AM EDTFLASH FLOOD1 W Sinking Spring, PAFLASH FLOODING FORCED THE CLOSURE OF PARK AVENUE AT PENN AVENUE. TIME BASED ON DISPATCH REPORT.

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, 8.1 hours before the alert went out and 197 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 00:00Z on 2021-08-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 711 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 00:00Z on 2021-08-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 76 square meters per square second.1939Sfc1 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
711 J/kg
Mixed-layer CIN
-55 J/kg
Mixed-layer LCL
1370 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
76 m²/s²
0-3 km storm-relative helicity
99 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

518 
WGUS51 KPHI 280806
FFWPHI
PAC011-281100-
/O.NEW.KPHI.FF.W.0060.210828T0806Z-210828T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
406 AM EDT Sat Aug 28 2021

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Central Berks County in eastern Pennsylvania...

* Until 700 AM EDT.

* At 406 AM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 4 inches of rain 
  have fallen since last evening. 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...
  Reading, Wyomissing, Fleetwood, Sinking Spring, Laureldale, 
  Womelsdorf, Wernersville, Robesonia, Leesport, Shoemakersville, 
  Bernville, and Lyons.

This includes the following highways...
	Interstate 176 in Pennsylvania between mile markers 6 and 11.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4036 7622 4038 7624 4053 7601 4055 7591
      4047 7573 4019 7594 4034 7618 4036 7621

FLASH FLOOD...RADAR INDICATED

$$

CMS
3 follow-up statements
631 
WGUS71 KPHI 280836
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
436 AM EDT Sat Aug 28 2021

PAC011-281100-
/O.CON.KPHI.FF.W.0060.000000T0000Z-210828T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-
436 AM EDT Sat Aug 28 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 AM EDT THIS MORNING 
FOR CENTRAL BERKS COUNTY...

At 436 AM EDT, local law enforcement reported flash flooding in 
Spring Township and in the Laureldale area. Several roads are 
closed. Flash flooding is already occurring.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Law enforcement 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...
  Reading, Wyomissing, Fleetwood, Sinking Spring, Laureldale, 
  Womelsdorf, Wernersville, Robesonia, Leesport, Shoemakersville, 
  Bernville, and Lyons.

This includes the following highways...
	Interstate 176 in Pennsylvania between mile markers 6 and 11.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4036 7622 4038 7624 4053 7601 4055 7591
      4047 7573 4019 7594 4034 7618 4036 7621

FLASH FLOOD...OBSERVED

$$

CMS
559 
WGUS71 KPHI 281008
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
608 AM EDT Sat Aug 28 2021

PAC011-281100-
/O.CON.KPHI.FF.W.0060.000000T0000Z-210828T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-
608 AM EDT Sat Aug 28 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 AM EDT THIS MORNING 
FOR CENTRAL BERKS COUNTY...

At 608 AM EDT, local law enforcement reported flash flooding in 
portions of Sinking Spring and South Heidelberg Township. Several 
roads remain closed. Though the heavy rainfall has ended, runoff 
will continue to cause flooding in the warned area.

HAZARD...Flash flooding caused by heavy rain.

SOURCE...Law enforcement 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...
  Reading, Wyomissing, Fleetwood, Sinking Spring, Laureldale, 
  Womelsdorf, Wernersville, Robesonia, Leesport, Shoemakersville, 
  Bernville, and Lyons.

This includes the following highways...
	Interstate 176 in Pennsylvania between mile markers 6 and 11.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4036 7622 4038 7624 4053 7601 4055 7591
      4047 7573 4019 7594 4034 7618 4036 7621

FLASH FLOOD...OBSERVED

$$

CMS
512 
WGUS71 KPHI 281053
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
653 AM EDT Sat Aug 28 2021

PAC011-281103-
/O.EXP.KPHI.FF.W.0060.000000T0000Z-210828T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-
653 AM EDT Sat Aug 28 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 7 AM EDT THIS MORNING FOR 
CENTRAL BERKS COUNTY...

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

LAT...LON 4036 7622 4038 7624 4053 7601 4055 7591
      4047 7573 4019 7594 4034 7618 4036 7621

$$

CMS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 28, 2:47 AM EDTAreal Flood AdvisoryPHIBerks2 hr
Aug 28, 3:06 AM EDTAreal Flood AdvisoryPHIChester, Delaware, Montgomery, Philadelphia2 hr
Aug 28, 8:07 AM EDTAreal Flood AdvisoryPHIBucks, Montgomery, Northampton3 hr
Aug 28, 9:06 AM EDTFlash Flood WarningPHIBucks, Montgomery, Northampton3 hr
Aug 28, 11:57 AM EDTFlash Flood WarningPHIDelaware, Montgomery, Philadelphia3 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2021Every flash 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.