Alert archive / Pennsylvania / Flash Flood Warnings in 2021

Flash Flood Warning 59, NWS Philadelphia/Mount Holly

August 27, 2021Berks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 27, 2021, 7:17 PM EDT for Berks County, Pennsylvania. It was in force for 3 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: Aug 27, 2021, 7:17 PM EDT (23:17 UTC)
Expired: Aug 27, 2021, 9:56 PM 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), 156 km from the middle of the area, began a volume at 23:18 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, 11.3 hours before the alert went out and 199 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: 780 J/kg
Mixed-layer CIN: -92 J/kg
Mixed-layer LCL: 983 m above ground
0-6 km bulk shear: 8 kt
0-1 km storm-relative helicity: 13 m²/s²
0-3 km storm-relative helicity: 41 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

703 
WGUS51 KPHI 272317
FFWPHI
PAC011-280315-
/O.NEW.KPHI.FF.W.0059.210827T2317Z-210828T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
717 PM EDT Fri Aug 27 2021

The National Weather Service in Mount Holly has issued a

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

* Until 1115 PM EDT.

* At 717 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 3 inches of rain 
  have fallen. Additional rainfall amounts of 0.5 to 1 inch 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...
  Wernersville, Leesport, Bernville, Strausstown, and Fairview Hgts.

This includes the following highways...
	Interstate 78 in Pennsylvania between mile markers 14 and 21.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4051 7616 4044 7591 4031 7606 4048 7632

FLASH FLOOD...RADAR INDICATED

$$

Kruzdlo

1 follow-up statement

474 
WGUS71 KPHI 280156
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
956 PM EDT Fri Aug 27 2021

PAC011-280206-
/O.CAN.KPHI.FF.W.0059.000000T0000Z-210828T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-
956 PM EDT Fri Aug 27 2021

...FLASH FLOOD WARNING IS CANCELLED FOR WEST CENTRAL BERKS COUNTY...

The heavy rain is coming to an end. The Flash Flood Warning is 
cancelled.

A Flash Flood Watch remains in effect until 200 AM EDT Sunday for 
portions of northern Delaware...New Jersey...and Pennsylvania.

LAT...LON 4051 7616 4044 7591 4031 7606 4048 7632

$$

Kruzdlo

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 27, 1:20 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	2 hr
Aug 27, 1:33 PM EDT	Areal Flood Advisory	PHI	Bucks, Delaware, Philadelphia	83 min
Aug 27, 1:36 PM EDT	Special Weather Statement	PHI	Monroe	24 min
Aug 27, 1:52 PM EDT	Severe Thunderstorm Warning	PHI	Chester	53 min
Aug 27, 2:12 PM EDT	Special Weather Statement	PHI	Northampton	33 min
Aug 27, 2:18 PM EDT	Areal Flood Advisory	PHI	Chester	93 min
Aug 27, 2:32 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe, Northampton	28 min
Aug 27, 2:33 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe, Northampton	109 min
Aug 27, 2:42 PM EDT	Severe Thunderstorm Warning	PHI	Chester	14 min
Aug 27, 3:07 PM EDT	Severe Thunderstorm Warning	PHI	Northampton	24 min
Aug 27, 3:44 PM EDT	Special Weather Statement	PHI	Delaware	31 min
Aug 27, 5:29 PM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery	3 hr
Aug 27, 6:29 PM EDT	Areal Flood Advisory	PHI	Berks	3 hr
Aug 27, 6:41 PM EDT	Special Weather Statement	PHI	Berks	34 min

Nearby

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