Alert archive / Pennsylvania / Flash Flood Warnings in 2013

Flash Flood Warning 36, NWS Philadelphia/Mount Holly

July 12, 2013Delaware County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 12, 2013, 10:01 AM EDT for Delaware 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 12, 2013, 10:01 AM EDT (14:01 UTC)
Expired: Jul 12, 2013, 2:00 PM EDT
In force: 4 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 14:04 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, 2.0 hours before the alert went out and 200 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: 892 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: -59 m²/s²
0-3 km storm-relative helicity: 194 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.

427 
WGUS51 KPHI 121401
FFWPHI
PAC045-121800-
/O.NEW.KPHI.FF.W.0036.130712T1401Z-130712T1800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1001 AM EDT FRI JUL 12 2013

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL DELAWARE COUNTY...

* UNTIL 200 PM EDT...

* AT 951 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM OVER CENTRAL DELAWARE COUNTY. 
  OVER TWO INCHES HAVE FALLEN DURING THE LAST HOUR. 

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO RURAL AREAS
  OF CENTRAL DELAWARE COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS 
IMMINENT. MOST FLOOD RELATED DEATHS OCCUR IN AUTOMOBILES. DO NOT 
ATTEMPT TO CROSS WATER COVERED BRIDGES...DIPS...OR LOW WATER 
CROSSINGS. TURN AROUND...DON'T DROWN! NEVER TRY TO CROSS A FLOWING 
STREAM...EVEN A SMALL ONE...ON FOOT. TO ESCAPE RISING WATER MOVE UP 
TO HIGHER GROUND.

&&

LAT...LON 3992 7551 3999 7534 3991 7533 3987 7548

$$

KRUZDLO

1 follow-up statement

284 
WGUS71 KPHI 121702
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
102 PM EDT FRI JUL 12 2013

PAC045-121713-
/O.CAN.KPHI.FF.W.0036.000000T0000Z-130712T1800Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DELAWARE PA-
102 PM EDT FRI JUL 12 2013

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR CENTRAL DELAWARE
COUNTY...

COUNTY OFFICIALS INDICATED THAT THE FLOODING HAS SUBSIDED AND ALL 
ROADS HAVE REOPENED.

LAT...LON 3992 7551 3999 7534 3991 7533 3987 7548

$$

KRUZDLO

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 4:08 AM EDT	Flash Flood Watch	PHI	Chester, Delaware, Montgomery, Philadelphia	17 hr
Jul 12, 9:13 AM EDT	Areal Flood Advisory	PHI	Chester, Delaware, Montgomery	4 hr
Jul 12, 10:49 AM EDT	Areal Flood Advisory	PHI	Chester	4 hr
Jul 12, 4:04 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	4 hr
Jul 12, 4:47 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Chester, Lehigh, Montgomery, Northampton	4 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2013 Every flash flood warning in 2013

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.