Alert archive / Pennsylvania / Flash Flood Warnings in 2017

Flash Flood Warning 33, NWS Philadelphia/Mount Holly

July 28, 2017Berks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 28, 2017, 9:25 PM EDT for Berks County, 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: Jul 28, 2017, 9:25 PM EDT (01:25 UTC)
Expired: Jul 29, 2017, 1:30 AM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Berks County, PA

The radar

The Philadelphia radar (KDIX), 131 km from the middle of the area, began a volume at 01:28 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 00:00Z, 1.4 hours before the alert went out and 206 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: 83 J/kg
Mixed-layer CIN: -56 J/kg
Mixed-layer LCL: 676 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 50 m²/s²
0-3 km storm-relative helicity: 43 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

718 
WGUS51 KPHI 290125
FFWPHI
PAC011-290530-
/O.NEW.KPHI.FF.W.0033.170729T0125Z-170729T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
925 PM EDT FRI JUL 28 2017

The National Weather Service in Mount Holly NJ has issued a

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

* Until 130 AM EDT

* At 924 PM EDT...Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. One to one and a half inches of 
  rain have fallen in less than an hour with additional rainfall 
  expected. Flash flooding is expected to begin shortly in the areas 
  of heaviest rain.

* Some locations that could experience flooding include...
  Reading, Wyomissing, Birdsboro, Fleetwood, Sinking Spring,
  Laureldale, Womelsdorf, Wernersville, Newmanstown, Leesport,
  Adamstown, Bally, Bernville, Bechtelsville, Spring Ridge, Fairview
  Hgts, Shillington, West Reading, Boyertown and Mount Penn.

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.

&&

LAT...LON 4045 7555 4024 7570 4022 7601 4049 7642

$$

Robertson

2 follow-up statements

477 
WGUS71 KPHI 290232
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1032 PM EDT FRI JUL 28 2017

PAC011-290530-
/O.CON.KPHI.FF.W.0033.000000T0000Z-170729T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-
1032 PM EDT FRI JUL 28 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 130 AM EDT FOR
CENTRAL BERKS COUNTY...

At 1027 PM EDT...Doppler radar indicated that the heaviest rain was 
moving out of the warned area. Up to two inches of rain have fallen. 
With runoff expected, the Flash Flood Warning will remain in effect 
until 130 am.

Some locations that could experience flooding include...
Reading, Wyomissing, Birdsboro, Fleetwood, Sinking Spring,
Laureldale, Womelsdorf, Wernersville, Newmanstown, Leesport,
Adamstown, Bally, Bernville, Bechtelsville, Spring Ridge, Fairview
Hgts, Shillington, West Reading, Boyertown and Mount Penn.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4045 7555 4024 7570 4022 7601 4049 7642

$$

Kruzdlo

398 
WGUS71 KPHI 290332
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1132 PM EDT FRI JUL 28 2017

PAC011-290341-
/O.CAN.KPHI.FF.W.0033.000000T0000Z-170729T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-
1132 PM EDT FRI JUL 28 2017

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

The heaviest rain has ended. Flash flooding is no longer expected to 
pose a threat. Please continue to heed any remaining road closures.

LAT...LON 4045 7555 4024 7570 4022 7601 4049 7642

$$

Kruzdlo

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 28, 8:29 PM EDT	Special Weather Statement	PHI	Berks	46 min
Jul 28, 8:48 PM EDT	Areal Flood Advisory	PHI	Berks	4 hr
Jul 29, 3:03 AM EDT	Areal Flood Advisory	PHI	Chester	4 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2017 Every flash flood warning in 2017

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.