Alert archive / Pennsylvania / Flash Flood Warnings in 2009
Flash Flood Warning 38, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 12, 2009, 5:18 PM EDT for Bucks County, Chester County, 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
- Aug 12, 2009, 5:18 PM EDT (21:18 UTC)
- Expired
- Aug 12, 2009, 7:37 PM EDT
- In force
- 2 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Bucks County, PA, Chester County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 92 km from the middle of the area, began a volume at 21:18 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
Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 9.3 hours before the alert went out and 121 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.
- Mixed-layer CAPE
- 402 J/kg
- Mixed-layer CIN
- -103 J/kg
- Mixed-layer LCL
- 1048 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 39 m²/s²
- 0-3 km storm-relative helicity
- 111 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 1.3
The text
As transmitted, in the capitals the NWS used until 2016.
000
WGUS51 KPHI 122118
FFWPHI
PAC017-029-091-130115-
/O.NEW.KPHI.FF.W.0038.090812T2118Z-090813T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
518 PM EDT WED AUG 12 2009
THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A
* FLASH FLOOD WARNING FOR...
NORTHWESTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
NORTHEASTERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
* UNTIL 915 PM EDT
* AT 514 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
SLOW MOVING THUNDERSTORMS WITH TORRENTIAL RAIN ACROSS PORTIONS OF
THE WARNED AREA. RAINFALL AMOUNTS OF ONE TO THREE INCHES ARE
POSSIBLE.
* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
SPRINGTOWN...REVERE...PLEASANT VALLEY...PIPERSVILLE...OTTSVILLE...
GERYVILLE...GARDENVILLE...ERWINNA...BEDMINSTER...FERNDALE...TINICUM
TOWNSHIP...ROBESONIA...RIEGELSVILLE...QUAKERTOWN...PERKASIE...GREEN
LANE...EAST GREENVILLE AND DUBLIN
PRECAUTIONARY/PREPAREDNESS ACTIONS...
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 4024 7570 4044 7552 4042 7549 4050 7541
4062 7520 4056 7519 4056 7511 4053 7507
4042 7506 4040 7502 4041 7500 4040 7497
3995 7564 4014 7588
$$
KRUZDLO1 follow-up statement
000
WGUS71 KPHI 122337
FFSPHI
FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
737 PM EDT WED AUG 12 2009
PAC017-029-091-122347-
/O.CAN.KPHI.FF.W.0038.000000T0000Z-090813T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CHESTER PA-MONTGOMERY PA-BUCKS PA-
737 PM EDT WED AUG 12 2009
...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR NORTHWESTERN
BUCKS...MONTGOMERY AND NORTHEASTERN CHESTER COUNTIES...
THE HEAVY RAIN HAS MOVED OUT OF THE AREA. THE FLASH FLOOD WARNING
HAS BEEN CANCELLED.
LAT...LON 4024 7570 4044 7552 4042 7549 4050 7541
4062 7520 4056 7519 4056 7511 4053 7507
4042 7506 4040 7502 4041 7500 4040 7497
3995 7564 4014 7588
$$
KRUZDLOThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 12, 6:03 PM EDT | Areal Flood Advisory | PHI | Monroe | 4 hr |
| Aug 12, 6:52 PM EDT | Areal Flood Advisory | PHI | Carbon, Monroe | 3 hr |
Nearby
Flash Flood Warnings in Pennsylvania, 2009Every flash flood warning in 2009
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.