Alert archive / Pennsylvania / Flash Flood Warnings in 2011
Flash Flood Warning 64, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 11, 2011, 9:56 PM EDT for 5 counties in Pennsylvania. It was in force for 4 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
- Sep 11, 2011, 9:56 PM EDT (01:56 UTC)
- Expired
- Sep 12, 2011, 2:00 AM EDT
- In force
- 4 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 71 km from the middle of the area, began a volume at 01:56 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
Brookhaven, NY (KOKX), launched 00:00Z, 1.9 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.
- Mixed-layer CAPE
- 30 J/kg
- Mixed-layer CIN
- -70 J/kg
- Mixed-layer LCL
- 549 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 84 m²/s²
- 0-3 km storm-relative helicity
- 122 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
The text
As transmitted, in the capitals the NWS used until 2016.
758
WGUS51 KPHI 120156
FFWPHI
PAC017-029-045-091-101-120600-
/O.NEW.KPHI.FF.W.0064.110912T0156Z-110912T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
956 PM EDT SUN SEP 11 2011
THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A
* FLASH FLOOD WARNING FOR...
DELAWARE COUNTY...
PHILADELPHIA COUNTY...
EASTERN CHESTER COUNTY...
MONTGOMERY COUNTY...
SOUTHERN BUCKS COUNTY...
* UNTIL 200 AM EDT...
* AT 950 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
VERY HEAVY RAIN FROM THUNDERSTORMS APPROACHING THE AREA FROM BOTH
THE WEST AND THE SOUTH.
* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO AMBLER...
CHESTER...DOWNINGTOWN...DOYLESTOWN...KING OF PRUSSIA...LANGHORNE...
LEVITTOWN...NORRISTOWN...PHILADELPHIA...WEST CHESTER AND WILLOW
GROVE.
ADDITIONAL RAINFALL AMOUNTS OF AN INCH OR TWO ARE POSSIBLE IN THE
WARNED AREA.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
PLEASE REPORT FLOODING...HAIL OR WIND DAMAGE TO THE NATIONAL WEATHER
SERVICE BY CALLING TOLL FREE...1-877-633-6772.
FLOODING IS OCCURRING OR IS IMMINENT. MOST FLOOD RELATED DEATHS OCCUR
IN AUTOMOBILES. DO NOT ATTEMPT TO CROSS WATER COVERED BRIDGES...
DIPS...OR LOW WATER CROSSINGS. TURN AROUND...DON'T DROWN! NEVER TRY
TO CROSS A FLOWING STREAM...EVEN A SMALL ONE...ON FOOT. TO ESCAPE
RISING WATER MOVE UP TO HIGHER GROUND.
&&
LAT...LON 4007 7490 4006 7495 3995 7514 3989 7514
3985 7523 3985 7535 3983 7539 3985 7582
4044 7553 4042 7549 4050 7542 4020 7477
$$
IOVINO2 follow-up statements
506
WGUS71 KPHI 120345
FFSPHI
FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1145 PM EDT SUN SEP 11 2011
PAC017-029-045-091-101-120600-
/O.CON.KPHI.FF.W.0064.000000T0000Z-110912T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DELAWARE PA-PHILADELPHIA PA-CHESTER PA-MONTGOMERY PA-BUCKS PA-
1145 PM EDT SUN SEP 11 2011
...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 200 AM EDT FOR
SOUTHERN BUCKS...SOUTHEASTERN MONTGOMERY...EAST CENTRAL CHESTER...
PHILADELPHIA AND DELAWARE COUNTIES...
AT 1140 PM EDT...DOPPLER RADAR CONTINUED TO INDICATE THUNDERSTORMS
PRODUCING HEAVY RAIN OVER EXTREME SOUTHEASTERN PENNSYLVANIA.
LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO CHESTER...
MEDIA...PHILADELPHIA...LEVITTOWN AND NEWTOWN.
ADDITIONAL RAINFALL AMOUNTS OF UP TO AN INCH ARE POSSIBLE IN THE
WARNED AREA.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
IF YOU WILL BE DRIVING IN THE AREA...BE PREPARED FOR REDUCED
VISIBILITY DUE TO THE HEAVY RAIN. DO NOT DRIVE YOUR VEHICLE THROUGH
FLOOD WATERS. THE WATER MAY BE DEEPER THAN YOU THINK IT IS. YOU WILL
BE PUTTING YOURSELF IN DANGER AND YOU MAY DAMAGE YOUR VEHICLE.
PLEASE REPORT FLOODING...HAIL OR WIND DAMAGE BY CALLING YOUR LOCAL
LAW ENFORCEMENT OFFICIALS OR BY CALLING THE NATIONAL WEATHER SERVICE
TOLL FREE AT...1-877-633-6772.
&&
LAT...LON 4007 7490 4006 7495 3995 7514 3989 7514
3985 7523 3985 7535 3983 7539 3985 7573
4039 7518 4020 7477
$$
IOVINO809
WGUS71 KPHI 120421
FFSPHI
FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1221 AM EDT MON SEP 12 2011
PAC017-029-045-091-120430-
/O.CAN.KPHI.FF.W.0064.000000T0000Z-110912T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DELAWARE PA-CHESTER PA-MONTGOMERY PA-BUCKS PA-
1221 AM EDT MON SEP 12 2011
...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR SOUTHERN BUCKS...
SOUTHEASTERN MONTGOMERY...EAST CENTRAL CHESTER AND DELAWARE
COUNTIES...
THE WATER FROM THIS EVENING'S HEAVY RAINFALL WAS RECEDING AND IT NO
LONGER POSES A THREAT TO LIFE OR PROPERTY. THEREFORE...THE FLASH
FLOOD WARNING HAS BEEN CANCELLED.
LAT...LON 4004 7499 3995 7514 3989 7514 3985 7524
3988 7527 3994 7525 3998 7528 4002 7522
4006 7527 4009 7522 4005 7512 4013 7504
4013 7499 4011 7497
$$
PAC101-120600-
/O.CON.KPHI.FF.W.0064.000000T0000Z-110912T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
PHILADELPHIA PA-
1221 AM EDT MON SEP 12 2011
...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 200 AM EDT FOR
PHILADELPHIA COUNTY...
AT 1215 AM EDT...THERE WAS A THUNDERSTORM PRODUCING HEAVY RAIN OVER
PARTS OF PHILADELPHIA.
ADDITIONAL RAINFALL AMOUNTS OF UP TO AN INCH ARE POSSIBLE IN THE
WARNED AREA.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
IF YOU WILL BE DRIVING IN THE AREA...BE PREPARED FOR REDUCED
VISIBILITY DUE TO THE HEAVY RAIN. DO NOT DRIVE YOUR VEHICLE THROUGH
FLOOD WATERS. THE WATER MAY BE DEEPER THAN YOU THINK IT IS. YOU WILL
BE PUTTING YOURSELF IN DANGER AND YOU MAY DAMAGE YOUR VEHICLE.
PLEASE REPORT FLOODING...HAIL OR WIND DAMAGE BY CALLING YOUR LOCAL
LAW ENFORCEMENT OFFICIALS OR BY CALLING THE NATIONAL WEATHER SERVICE
TOLL FREE AT...1-877-633-6772.
&&
LAT...LON 4004 7499 3995 7514 3989 7514 3985 7524
3988 7527 3994 7525 3998 7528 4002 7522
4006 7527 4009 7522 4005 7512 4013 7504
4013 7499 4011 7497
$$
IOVINOThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 11, 8:19 PM EDT | Flash Flood Warning | PHI | Berks | 3 hr |
| Sep 11, 8:46 PM EDT | Areal Flood Advisory | PHI | Chester | 3 hr |
| Sep 11, 9:00 PM EDT | Flash Flood Warning | PHI | Chester | 3 hr |
| Sep 11, 9:14 PM EDT | Flash Flood Warning | PHI | Berks, Chester, Montgomery | 110 min |
| Sep 11, 9:14 PM EDT | Special Weather Statement | PHI | Berks, Chester, Lehigh, Montgomery | 61 min |
| Sep 11, 9:24 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 51 min |
| Sep 11, 9:34 PM EDT | Special Weather Statement | PHI | Philadelphia | 41 min |
| Sep 11, 9:54 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery | 51 min |
| Sep 11, 10:25 PM EDT | Special Weather Statement | PHI | Philadelphia | 65 min |
| Sep 11, 10:29 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware | 46 min |
| Sep 11, 10:44 PM EDT | Areal Flood Advisory | PHI | Chester | 107 min |
| Sep 11, 10:52 PM EDT | Special Weather Statement | PHI | Bucks, Delaware, Montgomery, Philadelphia | 83 min |
| Sep 11, 11:10 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Philadelphia | 65 min |
| Sep 12, 11:05 AM EDT | Coastal Flood Statement | PHI | Delaware, Philadelphia | 6 hr |
Nearby
Flash Flood Warnings in Pennsylvania, 2011Every flash flood warning in 2011
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.