Alert archive / Pennsylvania / Flash Flood Warnings in 2012

Flash Flood Warning 47, NWS Philadelphia/Mount Holly

September 3, 2012Delaware County, Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 3, 2012, 8:23 AM EDT for Delaware County, Pennsylvania; New Castle County, Delaware. It was in force for 82 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: Sep 3, 2012, 8:23 AM EDT (12:23 UTC)
Expired: Sep 3, 2012, 9:45 AM EDT
In force: 82 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties New Castle County, DE, Delaware County, PA

The radar

The Philadelphia radar (KDIX), 100 km from the middle of the area, began a volume at 12:22 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, 0.4 hours before the alert went out and 182 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: 383 J/kg
Mixed-layer CIN: -34 J/kg
Mixed-layer LCL: 718 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: 77 m²/s²
0-3 km storm-relative helicity: 86 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.

912 
WGUS51 KPHI 031223
FFWPHI
DEC003-PAC045-031345-
/O.NEW.KPHI.FF.W.0047.120903T1223Z-120903T1345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
823 AM EDT MON SEP 3 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  DELAWARE COUNTY...
  NORTHERN NEW CASTLE COUNTY...

* UNTIL 945 AM EDT...

* AT 816 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  VERY HEAVY RAIN OVER DELAWARE AND NORTHERN NEW CASTLE COUNTIES.    
  RAINFALL ESTIMATES OF AROUND 2 INCHES HAS FALLEN WITHIN THE LAST   
  HOUR.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO ARDEN...
  DELAWARE CITY...ELSMERE...NEW CASTLE...NEWARK...NEWPORT...PIKE
  CREEK...STANTON...TALLEYVILLE...WILMINGTON...WILMINGTON MANOR...
  CHESTER...LIMA...NETHER PROVIDENCE TOWNSHIP...SWARTHMORE...
  ASHLAND...BEAR...GLASGOW...HOCKESSIN...MOUNT PLEASANT...NORTH
  STAR...PORT PENN...SAINT GEORGES...CHELSEA...CONCORDVILLE...ELAM...
  GRADYVILLE AND NEWTOWN SQUARE.

ADDITIONAL RAINFALL AMOUNTS OF AN INCH TO TWO ARE POSSIBLE IN THE 
WARNED AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY.
RESIDENTS LIVING ALONG STREAMS AND CREEKS SHOULD TAKE IMMEDIATE
PRECAUTIONS TO PROTECT LIFE AND PROPERTY. NEVER ATTEMPT TO CROSS
SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT OR IN AN
AUTOMOBILE. TURN AROUND DON'T DROWN!

PLEASE REPORT FLOODING...HAIL OR WIND DAMAGE TO THE NATIONAL WEATHER
SERVICE BY CALLING TOLL FREE...1-877-633-6772.

&&

LAT...LON 3983 7564 3984 7559 3986 7560 4000 7542
      3992 7529 3985 7533 3976 7546 3972 7548
      3971 7551 3962 7560 3960 7560 3963 7557
      3951 7556 3948 7576 3973 7577

$$

ROBERTSON

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 3, 12:24 AM EDT	Areal Flood Advisory	PHI	Chester, Delaware	3 hr
Sep 3, 12:58 AM EDT	Flash Flood Warning	PHI	Chester, Delaware	5 hr
Sep 3, 4:19 AM EDT	River Flood Warning	PHI	Delaware	91 min
Sep 3, 4:44 AM EDT	Areal Flood Advisory	PHI	Chester, Montgomery	3 hr
Sep 3, 6:24 AM EDT	Areal Flood Warning	PHI	Chester	4 hr
Sep 3, 8:05 AM EDT	Areal Flood Advisory	PHI	Chester, Delaware, Montgomery, Philadelphia	3 hr
Sep 3, 9:15 AM EDT	Flash Flood Warning	PHI	Chester, Delaware, Montgomery	3 hr
Sep 3, 10:28 AM EDT	Special Weather Statement	PHI	Philadelphia	62 min
Sep 3, 11:14 AM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery, Philadelphia	2 hr
Sep 3, 12:04 PM EDT	Areal Flood Warning	PHI	Chester	4 hr
Sep 3, 2:44 PM EDT	Areal Flood Advisory	PHI	Chester	119 min
Sep 3, 3:00 PM EDT	Flash Flood Watch	PHI	Delaware, Philadelphia	49 hr
Sep 3, 5:27 PM EDT	Areal Flood Warning	PHI	Delaware	3 hr
Sep 3, 6:41 PM EDT	River Flood Warning	PHI	Delaware	2 hr
Sep 3, 6:05 AM EDT	Areal Flood Advisory	PHI	New Castle	3 hr
Sep 3, 7:31 AM EDT	Flash Flood Warning	PHI	New Castle	2 hr
Sep 3, 1:42 PM EDT	Special Weather Statement	PHI	Sussex	93 min
Sep 3, 1:48 PM EDT	Areal Flood Advisory	PHI	Kent, New Castle	3 hr
Sep 3, 1:53 PM EDT	Areal Flood Advisory	PHI	Kent, New Castle	3 hr
Sep 3, 2:19 PM EDT	Areal Flood Advisory	PHI	Sussex	114 min
Sep 3, 2:39 PM EDT	Special Weather Statement	PHI	New Castle	66 min
Sep 3, 3:14 PM EDT	Flash Flood Warning	PHI	Kent, New Castle	4 hr
Sep 3, 3:25 PM EDT	Tornado Warning	PHI	Kent	20 min
Sep 3, 3:58 PM EDT	Areal Flood Advisory	PHI	New Castle	3 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2012 Flash Flood Warnings in Delaware, 2012 Every flash 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.