Alert archive / Pennsylvania / Flash Flood Warnings in 2006

Flash Flood Warning 9, NWS Philadelphia/Mount Holly

June 3, 2006Chester County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 3, 2006, 1:20 AM EDT for Chester County, Philadelphia County, Pennsylvania. It was in force for 3 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jun 3, 2006, 1:20 AM EDT (05:20 UTC)
Expired: Jun 3, 2006, 4:15 AM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Counties, with a storm outline in the text

Counties Chester County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 93 km from the middle of the area, began a volume at 05:22 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.

What was reported inside it

Time	Report	Where	Remark
Jun 3, 1:20 AM EDT	FLASH FLOOD	West Grove, PA	FLASH FLOODING OCCURRING WITH SOME WATER RESCUES BEING CONDUCTED IN THE WEST GROVE AREA.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 5.3 hours before the alert went out and 197 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: 1897 J/kg
Mixed-layer CIN: -22 J/kg
Mixed-layer LCL: 789 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 162 m²/s²
0-3 km storm-relative helicity: 199 m²/s²
Significant tornado parameter: 1.2
Supercell composite: 7.2

Open this sounding in Storm Lab

The text

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

000 
WGUS51 KPHI 030522
FFWPHI
PAC029-101-030815-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
120 AM EDT SAT JUN 3 2006

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA
  THIS INCLUDES THE CITIES OF...WEST GOSHEN...WEST CHESTER...PAOLI...
  OXFORD...KENNETT SQUARE...DOWNINGTOWN...DEVON-BERWYN...CHESTERBROOK
  PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA
   
* UNTIL 415 AM EDT

* AT 113 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  THAT MORE SHOWERS AND THUNDERSTORMS ARE MOVING OVER THE WARNED
  AREA. CREEKS ARE RUNNING HIGH FROM THE PREVIOUS HEAVY RAIN AND
  COULD FLOOD WITH MUCH LESS RAIN. THIS INCLUDES THE HEADWATERS OF
  THE WHITE CLAY CREEK AND THE VALLEY CREEK IN CHESTER COUNTY AND
  THE FRANKFORD CREEK IN PHILADELPHIA.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO MALVERN AND
  EXTON

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.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

LAT...LON 3981 7605 3989 7593 4011 7548 4010 7543
      4006 7538 3994 7553 3993 7553 4001 7524
      4009 7523 4005 7513 4010 7507 4010 7497
      3988 7518 3993 7525 4000 7527 3991 7558
      3985 7561 3983 7569 3973 7580 3973 7607

$$
 
TFG

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 2, 8:28 PM EDT	Severe Thunderstorm Warning	PHI	Chester	62 min
Jun 2, 10:06 PM EDT	Flash Flood Warning	PHI	Delaware, Philadelphia	3 hr
Jun 3, 12:44 AM EDT	Flash Flood Warning	PHI	Delaware	3 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2006 Every flash flood warning in 2006

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.