Alert archive / Pennsylvania / Areal Flood Warnings in 2012

Areal Flood Warning 5, NWS Philadelphia/Mount Holly

May 16, 2012Delaware County, Pennsylvania

NWS Philadelphia/Mount Holly issued this areal flood warning at May 16, 2012, 4:27 AM EDT for Delaware 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: May 16, 2012, 4:27 AM EDT (08:27 UTC)
Expired: May 16, 2012, 7:01 AM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Delaware County, PA

The radar

The Philadelphia radar (KDIX), 87 km from the middle of the area, began a volume at 08:27 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, 8.5 hours before the alert went out and 204 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: 401 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 1311 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 5 m²/s²
0-3 km storm-relative helicity: 58 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

618 
WGUS41 KPHI 160827
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
427 AM EDT WED MAY 16 2012

PAC045-161130-
/O.NEW.KPHI.FA.W.0005.120516T0827Z-120516T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DELAWARE PA-
427 AM EDT WED MAY 16 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS IN...
  NORTHERN DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 730 AM EDT

* AT 425 AM EDT...THE CRUM CREEK REMAINS ABOVE FLOOD STAGE. WHILE 
THE HEAVIEST RAIN HAS EXITED THE AREA...RUNOFF FROM THE EARLIER 
HEAVY RAIN CONTINUES THE FLOODING THREAT IN THE WARNED AREA.

CREEKS AND STREAMS WILL CONTINUE TO FALL EARLY THIS MORNING...AND 
ALL FLOODING IS EXPECTED TO BE OVER BY 730 AM EDT.

A FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR HAS BEEN REPORTED.
STREAM RISES WILL BE SLOW AND FLASH FLOODING IS NOT EXPECTED.
HOWEVER...ALL INTERESTED PARTIES SHOULD TAKE NECESSARY PRECAUTIONS
IMMEDIATELY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

&&

LAT...LON 3997 7548 3999 7543 4000 7544 4006 7537
      3999 7530 3992 7544 3995 7550

$$

HAYES

1 follow-up statement

984 
WGUS81 KPHI 161101
FLSPHI

FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
701 AM EDT WED MAY 16 2012

PAC045-161111-
/O.CAN.KPHI.FA.W.0005.000000T0000Z-120516T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DELAWARE PA-
701 AM EDT WED MAY 16 2012

...THE FLOOD WARNING HAS BEEN CANCELLED FOR URBAN AREAS AND SMALL
STREAMS IN NORTHERN DELAWARE COUNTY...

LAT...LON 3997 7548 3999 7543 4000 7544 4006 7537
      3999 7530 3992 7544 3995 7550

$$

HAYES

The office that day

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

Issued	Product	Office	Counties	Lasted
May 15, 8:19 PM EDT	Special Weather Statement	PHI	Bucks	86 min
May 15, 8:46 PM EDT	Areal Flood Warning	PHI	Northampton	76 min
May 15, 9:00 PM EDT	Special Weather Statement	PHI	Berks	90 min
May 15, 9:49 PM EDT	Special Weather Statement	PHI	Berks, Bucks, Chester, Lehigh, Montgomery	86 min
May 15, 10:45 PM EDT	Areal Flood Advisory	PHI	Chester	57 min
May 15, 11:05 PM EDT	Special Weather Statement	PHI	Bucks, Chester, Delaware, Montgomery	55 min
May 15, 11:24 PM EDT	Areal Flood Advisory	PHI	Chester, Montgomery	116 min
May 15, 11:38 PM EDT	Areal Flood Warning	PHI	Chester, Montgomery	4 hr
May 16, 12:12 AM EDT	Areal Flood Advisory	PHI	Chester, Delaware, Montgomery	3 hr
May 16, 12:20 AM EDT	Special Weather Statement	PHI	Delaware, Philadelphia	55 min
May 16, 12:34 AM EDT	Flash Flood Warning	PHI	Chester, Delaware, Montgomery	4 hr
May 16, 2:37 AM EDT	Areal Flood Warning	PHI	Philadelphia	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.