Alert archive / Pennsylvania / Areal Flood Warnings in 2020

Areal Flood Warning 39, NWS Philadelphia/Mount Holly

August 12, 2020Berks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this areal flood warning at Aug 12, 2020, 5:09 PM EDT for Berks County, Pennsylvania. It was in force for 51 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 12, 2020, 5:09 PM EDT (21:09 UTC)
Expired: Aug 12, 2020, 6:00 PM EDT
In force: 51 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Berks County, PA

The radar

The Philadelphia radar (KDIX), 134 km from the middle of the area, began a volume at 21:11 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, 9.2 hours before the alert went out and 196 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: 127 J/kg
Mixed-layer CIN: -149 J/kg
Mixed-layer LCL: 1202 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 0 m²/s²
0-3 km storm-relative helicity: 48 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

672 
WGUS41 KPHI 122109
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
509 PM EDT Wed Aug 12 2020

PAC011-122315-
/O.NEW.KPHI.FA.W.0039.200812T2109Z-200812T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-
509 PM EDT Wed Aug 12 2020

The National Weather Service in Mount Holly NJ has issued a

* Flood Warning for...
  Southeastern Berks County in eastern Pennsylvania...

* Until 715 PM EDT.

* At 508 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain which may cause flooding in the southern portions of 
  Berks County. 

* Some locations that could experience flooding 
  include... Reading, Wyomissing, Birdsboro, Laureldale, New Morgan, 
  Spring Ridge, Shillington, West Reading, Mount Penn, Mohnton, 
  Kenhorst, St. Lawrence, Wyomissing Hills, West Lawn, Lorane, 
  Reiffton, West Wyomissing, Flying Hills and Whitfield.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

A Flood Warning means that flooding is imminent or occurring. All
interested parties should take necessary precautions immediately.

&&

LAT...LON 4041 7598 4037 7571 4014 7587 4017 7593
      4023 7603

$$

JJM

1 follow-up statement

785 
WGUS81 KPHI 122200
FLSPHI

Flood Statement
National Weather Service Mount Holly NJ
600 PM EDT Wed Aug 12 2020

PAC011-122209-
/O.CAN.KPHI.FA.W.0039.000000T0000Z-200812T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-
600 PM EDT Wed Aug 12 2020

...THE FLOOD WARNING HAS BEEN CANCELLED FOR SOUTHEASTERN BERKS
COUNTY...

Heavy rain has moved out of the area, so the threat of flooding has 
diminished. The flood warning has therefore been cancelled.

LAT...LON 4041 7598 4037 7571 4014 7587 4017 7593
      4023 7603

$$

JJM

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 12, 11:48 AM EDT	Special Weather Statement	PHI	Philadelphia	27 min
Aug 12, 12:43 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	3 hr
Aug 12, 1:12 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	48 min
Aug 12, 1:47 PM EDT	Flash Flood Warning	PHI	Chester, Delaware	2 hr
Aug 12, 1:54 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	51 min
Aug 12, 2:04 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	21 min
Aug 12, 2:40 PM EDT	Flash Flood Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	3 hr
Aug 12, 2:44 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	46 min
Aug 12, 3:20 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	29 min
Aug 12, 3:36 PM EDT	Flash Flood Warning	PHI	Chester	108 min
Aug 12, 5:04 PM EDT	Areal Flood Advisory	PHI	Lehigh, Northampton	56 min

Nearby

Areal Flood Warnings in Pennsylvania, 2020 Every areal flood warning in 2020

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.