Alert archive / Pennsylvania / Areal Flood Warnings in 2011
Areal Flood Warning 21, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this areal flood warning at Apr 17, 2011, 3:56 AM EDT for 5 counties in Pennsylvania. It was in force for 6 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
- Apr 17, 2011, 3:56 AM EDT (07:56 UTC)
- Expired
- Apr 17, 2011, 10:00 AM EDT
- In force
- 6 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), 54 km from the middle of the area, began a volume at 07:55 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, 7.9 hours before the alert went out and 205 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
- 470 m above ground
- 0-6 km bulk shear
- 50 kt
- 0-1 km storm-relative helicity
- 857 m²/s²
- 0-3 km storm-relative helicity
- 1017 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
026
WGUS41 KPHI 170756
FLWPHI
BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
356 AM EDT SUN APR 17 2011
PAC017-029-045-091-101-171400-
/O.NEW.KPHI.FA.W.0021.110417T0756Z-110417T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
DELAWARE PA-PHILADELPHIA PA-CHESTER PA-MONTGOMERY PA-BUCKS PA-
356 AM EDT SUN APR 17 2011
THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A
* FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS IN...
NORTHEASTERN DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
EXTREME EAST CENTRAL CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
SOUTHEASTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
SOUTHEASTERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
* UNTIL 1000 AM EDT
* SMALL CREEKS AND STREAMS CONTINUE TO RUN HIGH FROM YESTERDAYS
HEAVY RAINFALL. THE HEAVY RAINS HAVE ENDED SO THE RIVER LEVELS
WILL CONTINUE TO FALL THIS MORNING.
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.
LAT...LON 4012 7483 4007 7491 4006 7495 4003 7498
4001 7504 3998 7508 3998 7511 3995 7514
3990 7515 3984 7525 4004 7547 4023 7490
4013 7477
$$The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 16, 8:08 PM EDT | Areal Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 8 hr |
| Apr 16, 9:11 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 64 min |
| Apr 16, 9:18 PM EDT | River Flood Warning | PHI | Chester | 11 hr |
| Apr 16, 9:32 PM EDT | River Flood Warning | PHI | Delaware | 6 hr |
| Apr 16, 9:49 PM EDT | Special Weather Statement | PHI | Berks, Lehigh | 56 min |
| Apr 16, 11:09 PM EDT | River Flood Warning | PHI | Bucks | 13 hr |
| Apr 16, 11:11 PM EDT | River Flood Warning | PHI | Montgomery | 6 hr |
| Apr 17, 1:05 AM EDT | Areal Flood Warning | PHI | Berks | 5 hr |
| Apr 17, 6:07 AM EDT | Areal Flood Warning | PHI | Chester | 3 hr |
| Apr 17, 6:37 AM EDT | River Flood Warning | PHI | Chester, Delaware | 7 hr |
| Apr 17, 9:51 AM EDT | Coastal Flood Warning | PHI | Delaware, Philadelphia | 4 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.