Alert archive / Pennsylvania / Flash Flood Warnings in 2006

Flash Flood Warning 52, NWS Philadelphia/Mount Holly

July 21, 2006Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 21, 2006, 10:14 PM EDT for Montgomery County, Pennsylvania. It was in force for 2 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 21, 2006, 10:14 PM EDT (02:14 UTC)
Expired: Jul 22, 2006, 12:30 AM EDT
In force: 2 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Counties, with a storm outline in the text

County Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 94 km from the middle of the area, began a volume at 02:14 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, 2.2 hours before the alert went out and 219 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: 1388 J/kg
Mixed-layer CIN: -49 J/kg
Mixed-layer LCL: 999 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: -2 m²/s²
0-3 km storm-relative helicity: 54 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 220216
FFWPHI
PAC091-220430-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1014 PM EDT FRI JUL 21 2006

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 1230 AM EDT

* AT 1009 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR 
  INDICATED VERY HEAVY RAINFALL FROM THUNDERSTORMS OVER THE WARNED 
  AREA. ADDITIONAL HEAVY RAIN IS EXPECTED FOR NEXT HOUR OR TWO.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO SPRING
  MOUNT...GILBERTSVILLE AND EAST GREENVILLE

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW
LYING AREAS ARE SUBJECT TO FLOODING.

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 4014 7548 4018 7511 4043 7553 4026 7567

$$

AMC

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 9:32 PM EDT	Flash Flood Warning	PHI	Berks, Bucks, Lehigh, Northampton	3 hr
Jul 22, 12:11 AM EDT	Flash Flood Warning	PHI	Berks, Bucks, Lehigh	4 hr
Jul 22, 3:25 PM EDT	Flash Flood Warning	PHI	Montgomery	3 hr
Jul 22, 3:37 PM EDT	Severe Thunderstorm Warning	PHI	Delaware	53 min
Jul 22, 3:42 PM EDT	Severe Thunderstorm Warning	PHI	Philadelphia	57 min

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.