Alert archive / Pennsylvania / Areal Flood Warnings in 2012

Areal Flood Warning 34, NWS Philadelphia/Mount Holly

October 30, 2012Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this areal flood warning at Oct 30, 2012, 5:42 AM EDT for Chester County, Pennsylvania. It was in force for 5 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 30, 2012, 5:42 AM EDT (09:42 UTC)
Expired: Oct 30, 2012, 10:18 AM EDT
In force: 5 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Chester County, PA

The radar

The Philadelphia radar (KDIX), 114 km from the middle of the area, began a volume at 09:43 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, 9.7 hours before the alert went out and 181 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 569 m above ground
0-6 km bulk shear: 5 kt
0-1 km storm-relative helicity: 504 m²/s²
0-3 km storm-relative helicity: 1823 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

263 
WGUS41 KPHI 300942
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
542 AM EDT TUE OCT 30 2012

PAC029-310345-
/O.NEW.KPHI.FA.W.0034.121030T0942Z-121031T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CHESTER PA-
542 AM EDT TUE OCT 30 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLOOD WARNING FOR...
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 1145 PM EDT TUESDAY

* AT 535 AM EDT, FLOODING CONTINUED ALONG STREAMS AND CREEKS, AND IN
  AREAS OF POOR DRAINAGE IN CHESTER COUNTY. AMONG THE WATERWAYS
  AFFECTED ARE THE BRANDYWINE CREEK AND IT TRIBUTARIES AND THE
  FRENCH CREEK.

* FROM THREE TO FIVE INCHES OF RAIN HAVE FALLEN IN MUCH OF THE
  COUNTY. AN ADDITIONAL QUARTER TO HALF INCH OF RAIN IS POSSIBLE AT
  MANY LOCATIONS TODAY. FLOODING IS EXPECTED TO CONTINUE IN PARTS OF
  THE COUNTY INTO TONIGHT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DRIVING INTO FLOOD WATERS COULD PUT YOUR LIFE AT RISK AND COST YOU
THOUSANDS OF DOLLARS IN VEHICLE REPAIRS. FLOOD WATERS MAY BE DEEPER
THAN YOU THINK. TURN AROUND AND FIND AN ALTERNATE ROUTE.

LAT...LON 3974 7609 3987 7599 3996 7599 4003 7594
      4011 7594 4024 7571 4022 7561 4023 7559
      4015 7553 4006 7538 3999 7544 3999 7543
      3987 7560 3984 7558 3981 7570 3972 7578
      3972 7613

$$

IOVINO

1 follow-up statement

142 
WGUS81 KPHI 301418
FLSPHI

FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1018 AM EDT TUE OCT 30 2012

PAC029-301425-
/O.CAN.KPHI.FA.W.0034.000000T0000Z-121031T0345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CHESTER PA-
1018 AM EDT TUE OCT 30 2012

...THE FLOOD WARNING HAS BEEN CANCELLED FOR CHESTER COUNTY...

CREEK AND STREAM LEVELS CONTINUE TO FALL. AS A RESULT, THE FLOOD 
WARNING FOR CHESTER COUNTY HAS BEEN CANCELLED. HOWEVER, A FLOOD 
WARNING REMAINS IN EFFECT FOR THE MAIN STEM OF THE BRANDYWINE CREEK 
INTO THIS AFTERNOON.

LAT...LON 3974 7609 3987 7599 3996 7599 4003 7594
      4011 7594 4024 7571 4022 7561 4023 7559
      4015 7553 4006 7538 3999 7544 3999 7543
      3987 7560 3984 7558 3981 7570 3972 7578
      3972 7613

$$

IOVINO

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 30, 12:48 AM EDT	Areal Flood Advisory	PHI	Bucks, Carbon, Lehigh, Monroe, Northampton, Philadelphia	6 hr
Oct 30, 4:51 AM EDT	River Flood Warning	PHI	Montgomery	5 hr
Oct 30, 4:51 AM EDT	River Flood Warning	PHI	Chester, Montgomery, Philadelphia	5 hr
Oct 30, 6:03 AM EDT	Coastal Flood Advisory	PHI	Delaware, Philadelphia	20 hr
Oct 30, 8:48 AM EDT	Wind Advisory	PHI	Berks, Carbon, Delaware, Lehigh, Monroe, Northampton and 1 more	3 hr

Nearby

Areal Flood Warnings in Pennsylvania, 2012 Every areal flood warning in 2012

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.