Alert archive / Pennsylvania / Flash Flood Warnings in 2005

Flash Flood Warning 15, NWS Philadelphia/Mount Holly

July 17, 2005Montgomery County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 17, 2005, 6:58 PM EDT for Montgomery 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: Jul 17, 2005, 6:58 PM EDT (22:58 UTC)
Expired: Jul 17, 2005, 10:00 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Counties, with a storm outline in the text

Counties Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 68 km from the middle of the area, began a volume at 23:00 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
Jul 17, 7:15 PM EDT	FLASH FLOOD	Philadelphia, PA	SMALL STREAMS APPROACHING BANKFULL IN THE ROXBOROUGH SECTION OF THE CITY. 2.53 INCHES OF RAIN SINCE 630 AM.

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 11.0 hours before the alert went out and 214 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: 418 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 438 m above ground
0-6 km bulk shear: 9 kt
0-1 km storm-relative helicity: 44 m²/s²
0-3 km storm-relative helicity: 72 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 172300
FFWPHI
PAC091-101-180200-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
658 PM EDT SUN JUL 17 2005

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA
  NORTHWESTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA
  THIS INCLUDES THE CITY OF PHILADELPHIA

* UNTIL 1000 PM EDT

* AT 656 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 2 
  TO 3 INCHES OF RAIN HAD ALREADY FALLEN IN THE WARNED AREA...WITH   
  LOCALLY HIGHER AMOUNTS.

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

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 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. TURN AROUND, DONT DROWN.

LAT...LON 4009 7526 3997 7527 4000 7511 4014 7502
      4024 7518

$$

NIERENBERG

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 17, 4:01 PM EDT	Flash Flood Warning	PHI	Chester	3 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2005 Every flash flood warning in 2005

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.