Alert archive / Pennsylvania / Flash Flood Warnings in 2013

Flash Flood Warning 60, NWS Philadelphia/Mount Holly

August 13, 2013Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 13, 2013, 9:50 AM EDT for Chester 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: Aug 13, 2013, 9:50 AM EDT (13:50 UTC)
Expired: Aug 13, 2013, 1:45 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Chester County, PA

The radar

The Philadelphia radar (KDIX), 129 km from the middle of the area, began a volume at 13:52 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

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 1.8 hours before the alert went out and 57 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: 1840 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 567 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 129 m²/s²
0-3 km storm-relative helicity: 135 m²/s²
Significant tornado parameter: 1.3
Supercell composite: 7.8

Open this sounding in Storm Lab

The text

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

729 
WGUS51 KPHI 131350
FFWPHI
PAC029-131745-
/O.NEW.KPHI.FF.W.0060.130813T1350Z-130813T1745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
950 AM EDT TUE AUG 13 2013

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 145 PM EDT...

* AT 943 AM EDT...DOPPLER RADAR INDICATED ADDITIONAL RAIN IS         
  POSSIBLE OVER THE AREA FOR THE NEXT SEVERAL HOURS. HOWEVER...THE   
  HEAVIEST RAIN HAS MOVED EAST. UNFORTUNATELY...FLOODING CONTINUES   
  FROM EARLIER RAIN...SO THE FLASH FLOOD WARNING HAS BEEN EXTENDED   
  FOR CENTRAL CHESTER COUNTY.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING. 
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!

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 3983 7603 3985 7603 3988 7599 3997 7600
      4004 7594 4011 7595 4012 7593 4015 7586
      4016 7554 3981 7570 3977 7606

$$

FORECASTER:JJM

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 13, 2:45 AM EDT	Flash Flood Watch	PHI	Berks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more	9 hr
Aug 13, 5:15 AM EDT	Areal Flood Advisory	PHI	Berks, Chester, Montgomery	4 hr
Aug 13, 5:47 AM EDT	Flash Flood Warning	PHI	Chester	4 hr
Aug 13, 6:07 AM EDT	Areal Flood Advisory	PHI	Bucks, Lehigh, Northampton	7 hr
Aug 13, 6:07 AM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	53 min
Aug 13, 6:20 AM EDT	Areal Flood Advisory	PHI	Bucks, Delaware, Philadelphia	4 hr
Aug 13, 6:23 AM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	67 min
Aug 13, 6:32 AM EDT	Tornado Warning	PHI	Chester	43 min
Aug 13, 6:36 AM EDT	Flash Flood Warning	PHI	Chester, Delaware, Montgomery	8 hr
Aug 13, 7:05 AM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	40 min
Aug 13, 7:14 AM EDT	Flash Flood Warning	PHI	Berks	4 hr
Aug 13, 7:42 AM EDT	Special Weather Statement	PHI	Philadelphia	48 min
Aug 13, 7:54 AM EDT	Flash Flood Warning	PHI	Delaware, Montgomery, Philadelphia	8 hr
Aug 13, 7:54 AM EDT	Special Weather Statement	PHI	Delaware, Philadelphia	66 min
Aug 13, 8:07 AM EDT	River Flood Warning	PHI	Chester	9 hr
Aug 13, 8:20 AM EDT	Flash Flood Warning	PHI	Bucks	8 hr
Aug 13, 11:22 AM EDT	River Flood Warning	PHI	Chester, Delaware	16 hr
Aug 13, 2:18 PM EDT	Areal Flood Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	9 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.