Alert archive / Pennsylvania / Areal Flood Warnings in 2011
Areal Flood Warning 73, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this areal flood warning at Sep 6, 2011, 6:44 PM EDT for Chester County, Delaware County, Pennsylvania. It was in force for 15 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 6, 2011, 6:44 PM EDT (22:44 UTC)
- Expired
- Sep 7, 2011, 9:45 AM EDT
- In force
- 15 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Chester County, PA, Delaware County, PA
The radar
The Philadelphia radar (KDIX), 99 km from the middle of the area, began a volume at 22:45 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, 10.7 hours before the alert went out and 78 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 739 m above ground
- 0-6 km bulk shear
- 63 kt
- 0-1 km storm-relative helicity
- 63 m²/s²
- 0-3 km storm-relative helicity
- 555 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
549
WGUS41 KPHI 062244
FLWPHI
BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
644 PM EDT TUE SEP 6 2011
PAC029-045-070445-
/O.NEW.KPHI.FA.W.0073.110906T2244Z-110907T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DELAWARE PA-CHESTER PA-
644 PM EDT TUE SEP 6 2011
THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A
* FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS IN...
DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
NORTHERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
* UNTIL 1245 AM EDT
* AT 642 PM EDT...THE CRUM CREEK AT NEWTOWN SQUARE WAS AT 5.3 FEET.
FLOOD STAGE IS 6.0 FEET. ADDITIONAL RAINFALL WILL PUSH THE CREEK
OVER FLOOD STAGE LATER THIS EVENING.
* THE VALLEY CREEK AT VALLEY FORGE WAS 6.2 FEET. FLOOD STAGE IS 7.0
FEET. ADDITIONAL RAIN FALL WILL RESULT IN THE CREEK GOING INTO
FLOOD LATE THIS EVENING.
A FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR HAS BEEN REPORTED.
STREAM RISES WILL BE SLOW AND FLASH FLOODING IS NOT EXPECTED.
HOWEVER...ALL INTERESTED PARTIES SHOULD TAKE NECESSARY PRECAUTIONS
IMMEDIATELY.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF 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.
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 4014 7589 4025 7566 4016 7553 4015 7553
4014 7551 4013 7552 4012 7548 3995 7527
3986 7528 3985 7535 3982 7541 3984 7561
4003 7594
$$
HAYES2 follow-up statements
542
WGUS41 KPHI 070442
FLWPHI
BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1242 AM EDT WED SEP 7 2011
PAC029-045-070745-
/O.EXT.KPHI.FA.W.0073.000000T0000Z-110907T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DELAWARE PA-CHESTER PA-
1242 AM EDT WED SEP 7 2011
THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS EXTENDED THE
* FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS IN...
DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
NORTHERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
* UNTIL 345 AM EDT
* AT 1240 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
MOST OF THE HEAVY RAIN HAS MOVED OUT OF THE AREA.
HOWEVER...ADDITIONAL RAIN WILL BE MOVING IN OVER THE NEXT HOUR OR
SO. ALSO...SMALL STREAMS ARE STILL RUNNING HIGH FROM EARLIER RAIN.
THE AREAL FLOOD WARNING HAS THEREFORE BEEN EXTENDED UNTIL 345 AM
EDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLOODING IS OBSERVED ACT QUICKLY. DO NOT
STAY IN AREAS SUBJECT TO FLOODING WHEN WATER BEGINS RISING.
DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.
&&
LAT...LON 4014 7589 4025 7566 4016 7553 4015 7553
4014 7551 4013 7552 4012 7548 3995 7527
3986 7528 3985 7535 3982 7541 3984 7561
4003 7594
$$
JJM630
WGUS41 KPHI 070719
FLWPHI
BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
319 AM EDT WED SEP 7 2011
PAC029-045-071345-
/O.EXT.KPHI.FA.W.0073.000000T0000Z-110907T1345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DELAWARE PA-CHESTER PA-
319 AM EDT WED SEP 7 2011
THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS EXTENDED THE
* FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS IN...
DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
NORTHERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
* UNTIL 945 AM EDT
* AT 318 AM EDT SMALL STREAMS IN THE AREA WERE STILL RUNNING
HIGH FROM EARLIER RAIN. DOPPLER RADAR INDICATED ANOTHER LINE OF
SHOWERS MOVING IN FROM THE SOUTH. THE AREAL FLOOD WARNING HAS
THEREFORE BEEN EXTENDED UNTIL 945 AM EDT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF 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.
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 4014 7589 4025 7566 4016 7553 4015 7553
4014 7551 4013 7552 4012 7548 3995 7527
3986 7528 3985 7535 3982 7541 3984 7561
4003 7594
$$
JJMThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 5, 8:19 PM EDT | Areal Flood Advisory | PHI | Berks, Bucks, Lehigh, Montgomery, Northampton | 116 min |
| Sep 5, 9:32 PM EDT | Areal Flood Warning | PHI | Montgomery | 9 hr |
| Sep 5, 10:18 PM EDT | Flash Flood Warning | PHI | Lehigh, Northampton | 4 hr |
| Sep 5, 10:53 PM EDT | Areal Flood Advisory | PHI | Chester, Montgomery | 3 hr |
| Sep 5, 11:04 PM EDT | Areal Flood Advisory | PHI | Bucks | 6 hr |
| Sep 5, 11:25 PM EDT | Flash Flood Warning | PHI | Berks | 4 hr |
| Sep 6, 12:22 AM EDT | Areal Flood Advisory | PHI | Delaware, Philadelphia | 3 hr |
| Sep 6, 1:42 AM EDT | Areal Flood Advisory | PHI | Chester, Montgomery | 3 hr |
| Sep 6, 2:09 AM EDT | Areal Flood Advisory | PHI | Lehigh, Northampton | 3 hr |
| Sep 6, 3:40 AM EDT | Areal Flood Warning | PHI | Berks | 3 hr |
| Sep 6, 5:43 PM EDT | Areal Flood Advisory | PHI | Bucks, Chester, Delaware, Montgomery, Philadelphia | 3 hr |
| Sep 6, 5:49 PM EDT | Areal Flood Warning | PHI | Philadelphia | 20 hr |
| Sep 6, 6:10 PM EDT | Areal Flood Warning | PHI | Bucks, Monroe, Northampton | 71 hr |
| Sep 6, 6:32 PM EDT | Areal Flood Warning | PHI | Montgomery | 26 hr |
| Sep 6, 6:38 PM EDT | Areal Flood Warning | PHI | Montgomery, Philadelphia | 23 hr |
| Sep 6, 6:48 PM EDT | Areal Flood Warning | PHI | Bucks | 31 hr |
| Sep 6, 7:03 PM EDT | River Flood Warning | PHI | Chester | 16 hr |
| Sep 6, 7:41 PM EDT | River Flood Warning | PHI | Delaware | 5 hr |
| Sep 6, 7:52 PM EDT | River Flood Warning | PHI | Bucks | 52 hr |
Nearby
Areal Flood Warnings in Pennsylvania, 2011Every areal 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.