Alert archive / Pennsylvania / Flash Flood Warnings in 2007

Flash Flood Warning 20, NWS Philadelphia/Mount Holly

June 12, 2007Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 12, 2007, 4:00 PM EDT for Montgomery County, Pennsylvania. It was in force for 3 hr. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: Jun 12, 2007, 4:00 PM EDT (20:00 UTC)
Expired: Jun 12, 2007, 7:00 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Whole counties

County Montgomery County, PA

What was reported inside it

Time	Report	Where	Remark
Jun 12, 5:20 PM EDT	FLASH FLOOD	Fort Washington, PA	FLOODING ON THE PA TURNPIKE IN FORT WASHINGTON

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

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 8.0 hours before the alert went out and 103 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: 186 J/kg
Mixed-layer CIN: -92 J/kg
Mixed-layer LCL: 1120 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 25 m²/s²
0-3 km storm-relative helicity: 34 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.

000 
WGUS51 KPHI 122002
FFWPHI
PAC091-122300-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
400 PM EDT TUE JUN 12 2007

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 700 PM EDT

* AT 355 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM PERSISTENT THUNDERSTORMS OVER THE WARNED AREA.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO WILLOW
  GROVE AND AMBLER

THUNDERSTORMS HAVE DEPOSITED 2 TO 3 INCHES OF RAIN IS SOME PARTS OF 
LOWER MONTGOMERY COUNTY THIS AFTERNOON, ACCORDING TO RADAR ESTIMATES.

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.

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

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. 

LAT...LON 4005 7527 4009 7522 4007 7507 4017 7506
      4023 7523

$$

JRP

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 12, 12:56 PM EDT	Severe Thunderstorm Warning	PHI	Monroe	64 min
Jun 12, 1:12 PM EDT	Severe Thunderstorm Warning	PHI	Lehigh	26 min
Jun 12, 1:18 PM EDT	Severe Thunderstorm Warning	PHI	Berks	42 min
Jun 12, 2:00 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Lehigh, Northampton	30 min
Jun 12, 2:15 PM EDT	Severe Thunderstorm Warning	PHI	Montgomery, Philadelphia	30 min
Jun 12, 2:25 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	35 min
Jun 12, 2:48 PM EDT	Severe Thunderstorm Warning	PHI	Philadelphia	42 min
Jun 12, 3:20 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	40 min
Jun 12, 4:08 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	37 min
Jun 12, 5:46 PM EDT	Flash Flood Warning	PHI	Bucks	119 min

Nearby

Flash Flood Warnings in Pennsylvania, 2007 Every flash flood warning in 2007

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.