Alert archive / Pennsylvania / Flash Flood Warnings in 2010

Flash Flood Warning 7, NWS Philadelphia/Mount Holly

July 14, 2010Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 14, 2010, 2:32 AM EDT for Chester 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: Jul 14, 2010, 2:32 AM EDT (06:32 UTC)
Expired: Jul 14, 2010, 5:30 AM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Chester County, PA

The radar

The Philadelphia radar (KDIX), 127 km from the middle of the area, began a volume at 06:34 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, 6.5 hours before the alert went out and 169 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: 260 J/kg
Mixed-layer CIN: -84 J/kg
Mixed-layer LCL: 1054 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 86 m²/s²
0-3 km storm-relative helicity: 124 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

Open this sounding in Storm Lab

The text

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

877 
WGUS51 KPHI 140632
FFWPHI
PAC029-140930-
/O.NEW.KPHI.FF.W.0007.100714T0632Z-100714T0930Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
232 AM EDT WED JUL 14 2010

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF WEST CHESTER...

* UNTIL 530 AM EDT

* AT 225 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  HEAVY RAIN FALLING OVER THE COUNTY. MORE SHOWERS AND THUNDERSTORMS
  WITH VERY HEAVY RAIN WILL MOVE INTO THE AREA THIS MORNING... 
  PRODUCING AN ADDITIONAL 1 TO 2 INCHES OF RAIN. 
  
  VERY HEAVY RAIN FELL IN THESE LOCATIONS TUESDAY...AND THE 
  ADDITIONAL HEAVY RAIN WILL RESULT IN FLASH FLOODING. 

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO PUGHTOWN...
  MOUNT VERNON...LADENBERG...HOMEVILLE...GLENMOORE...COCHRANVILLE...
  CHESTER SPRINGS...WEST GROVE...PARKESBURG...PAOLI...OXFORD...
  MARSHALLTON...LIONVILLE...KENNETT SQUARE...HONEY BROOK...
  ELVERSON...DOWNINGTOWN AND COATESVILLE

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES
AS WELL AS OTHER DRAINAGE AREAS AND LOW LYING SPOTS.

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 3985 7603 3987 7601 3991 7602 4012 7592
      4023 7571 4005 7543 3973 7579 3972 7611

$$

HAYES

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 14, 1:29 AM EDT	Areal Flood Advisory	PHI	Berks	3 hr
Jul 14, 1:44 AM EDT	Special Weather Statement	PHI	Chester	61 min
Jul 14, 2:52 AM EDT	Flash Flood Warning	PHI	Delaware	3 hr
Jul 14, 3:27 AM EDT	Areal Flood Advisory	PHI	Carbon, Lehigh, Monroe, Northampton	3 hr
Jul 14, 3:46 AM EDT	Flash Flood Warning	PHI	Philadelphia	3 hr
Jul 14, 3:52 AM EDT	Special Weather Statement	PHI	Carbon	53 min
Jul 14, 3:58 AM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery	3 hr
Jul 14, 3:59 AM EDT	Areal Flood Advisory	PHI	Bucks	3 hr
Jul 14, 6:06 AM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	4 hr
Jul 14, 10:04 AM EDT	Areal Flood Advisory	PHI	Berks	3 hr
Jul 14, 10:15 AM EDT	Flash Flood Watch	PHI	Berks, Delaware, Lehigh, Northampton, Philadelphia	9 hr
Jul 14, 11:11 AM EDT	Flash Flood Warning	PHI	Berks	3 hr
Jul 14, 12:52 PM EDT	Areal Flood Advisory	PHI	Chester, Delaware	3 hr
Jul 14, 1:35 PM EDT	Areal Flood Advisory	PHI	Bucks, Delaware, Montgomery, Philadelphia	115 min
Jul 14, 2:11 PM EDT	Flash Flood Warning	PHI	Delaware, Montgomery, Philadelphia	109 min
Jul 14, 2:36 PM EDT	Areal Flood Advisory	PHI	Bucks	3 hr
Jul 14, 3:12 PM EDT	Flash Flood Warning	PHI	Bucks	63 min
Jul 14, 4:03 PM EDT	Areal Flood Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	79 min

Nearby

Flash Flood Warnings in Pennsylvania, 2010 Every flash flood warning in 2010

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.