Alert archive / Pennsylvania / Areal Flood Warnings in 2021
Areal Flood Warning 17, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this areal flood warning at Aug 19, 2021, 8:50 AM EDT for Montgomery County, Philadelphia County, Pennsylvania. It was in force for 3 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 19, 2021, 8:50 AM EDT (12:50 UTC)
- Expired
- Aug 19, 2021, 11:45 AM EDT
- In force
- 3 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Montgomery County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 69 km from the middle of the area, began a volume at 12:53 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 12:00Z, 0.8 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
- 1927 J/kg
- Mixed-layer CIN
- 0 J/kg
- Mixed-layer LCL
- 459 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 113 m²/s²
- 0-3 km storm-relative helicity
- 137 m²/s²
- Significant tornado parameter
- 1.0
- Supercell composite
- 5.5
The text
As transmitted.
262
WGUS41 KPHI 191250
FLWPHI
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
850 AM EDT Thu Aug 19 2021
PAC091-101-191445-
/O.NEW.KPHI.FA.W.0017.210819T1250Z-210819T1445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery PA-Philadelphia PA-
850 AM EDT Thu Aug 19 2021
The National Weather Service in Mount Holly has issued a
* Flood Warning for Small stream in...
South Central Montgomery County in southeastern Pennsylvania...
West Central Philadelphia County in southeastern Pennsylvania...
* Until 1045 AM EDT.
* At 850 AM EDT, The Wissahickon Creek at Wissahickon is approaching
flood stage. Flooding is expected to begin shortly.
* For Wissahickon Creek at Wissahickon:
At 8:00am the stage was 4.99 feet.
Flood Stage is 5 feet.
This includes the following streams and drainages...
Schuylkill and Lower Delaware.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 4008 7522 4006 7521 4005 7521 4004 7520
4003 7519 4001 7519 4000 7518 3998 7519
3999 7521 4000 7524 4003 7527
$$
BAH2 follow-up statements
789
WGUS41 KPHI 191437
FLWPHI
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
1037 AM EDT Thu Aug 19 2021
PAC091-101-191545-
/O.EXT.KPHI.FA.W.0017.000000T0000Z-210819T1545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery PA-Philadelphia PA-
1037 AM EDT Thu Aug 19 2021
The National Weather Service in Mount Holly has extended the
* Flood Warning for Small stream in...
South Central Montgomery County in southeastern Pennsylvania...
West Central Philadelphia County in southeastern Pennsylvania...
* Until 1145 AM EDT.
* At 1037 AM EDT, The Wissahickon Creek at Wissahickon is currently
in minor flood.
* For Wissahickon Creek at Wissahickon:
At 10:00am the stage was 5.04 feet.
Flood Stage is 5 feet.
This includes the following streams and drainages...
Schuylkill and Lower Delaware.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 4008 7522 4006 7521 4005 7521 4004 7520
4003 7519 4001 7519 4000 7518 3998 7519
3999 7521 4000 7524 4003 7527
$$
BAH494
WGUS81 KPHI 191544
FLSPHI
Flood Statement
National Weather Service Mount Holly NJ
1144 AM EDT Thu Aug 19 2021
PAC091-101-191554-
/O.EXP.KPHI.FA.W.0017.000000T0000Z-210819T1545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery PA-Philadelphia PA-
1144 AM EDT Thu Aug 19 2021
...THE SMALL STREAM FLOOD WARNING WILL EXPIRE AT 1145 AM EDT THIS
MORNING FOR SOUTH CENTRAL MONTGOMERY AND WEST CENTRAL PHILADELPHIA
COUNTIES...
The Wissahickon Creek at Wissahickon has fallen below flood stage.
Therefore, the flood warning has been allowed to expire.
LAT...LON 4008 7522 4006 7521 4005 7521 4004 7520
4003 7519 4001 7519 4000 7518 3998 7519
3999 7521 4000 7524 4003 7527
$$
BAHThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 18, 8:53 PM EDT | Areal Flood Advisory | PHI | Berks | 3 hr |
| Aug 18, 9:10 PM EDT | Areal Flood Advisory | PHI | Lehigh, Monroe, Northampton | 3 hr |
| Aug 18, 9:30 PM EDT | Flash Flood Warning | PHI | Berks | 2 hr |
| Aug 18, 9:35 PM EDT | Areal Flood Advisory | PHI | Berks, Lehigh | 3 hr |
| Aug 18, 9:45 PM EDT | Areal Flood Advisory | PHI | Berks | 3 hr |
| Aug 18, 9:47 PM EDT | Special Weather Statement | PHI | Berks | 58 min |
| Aug 18, 10:16 PM EDT | Flash Flood Warning | PHI | Berks, Lehigh | 3 hr |
| Aug 18, 10:44 PM EDT | Flash Flood Warning | PHI | Lehigh, Monroe, Northampton | 4 hr |
| Aug 18, 10:50 PM EDT | Flash Flood Warning | PHI | Bucks, Chester, Montgomery | 4 hr |
| Aug 18, 11:19 PM EDT | Areal Flood Advisory | PHI | Bucks, Lehigh, Northampton | 3 hr |
| Aug 18, 11:19 PM EDT | Special Weather Statement | PHI | Bucks, Chester, Montgomery | 41 min |
| Aug 18, 11:47 PM EDT | Flash Flood Warning | PHI | Chester | 2 hr |
| Aug 19, 12:04 AM EDT | Special Weather Statement | PHI | Bucks, Delaware, Montgomery | 71 min |
| Aug 19, 12:26 AM EDT | Tornado Warning | PHI | Bucks, Montgomery | 34 min |
| Aug 19, 12:31 AM EDT | Flash Flood Warning | PHI | Bucks, Chester, Delaware, Montgomery | 4 hr |
| Aug 19, 12:44 AM EDT | River Flood Warning | PHI | Chester | 5 hr |
| Aug 19, 12:47 AM EDT | Tornado Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 28 min |
| Aug 19, 12:48 AM EDT | Tornado Warning | PHI | Bucks | 27 min |
| Aug 19, 1:14 AM EDT | Special Weather Statement | PHI | Bucks, Delaware, Philadelphia | 91 min |
| Aug 19, 1:30 AM EDT | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 4 hr |
| Aug 19, 2:05 AM EDT | Areal Flood Advisory | PHI | Bucks | 3 hr |
| Aug 19, 2:13 AM EDT | Flash Flood Warning | PHI | Bucks, Philadelphia | 4 hr |
| Aug 19, 4:33 AM EDT | Areal Flood Warning | PHI | Chester, Delaware | 4 hr |
| Aug 19, 6:09 AM EDT | Areal Flood Warning | PHI | Bucks, Philadelphia | 3 hr |
| Aug 19, 10:40 AM EDT | Areal Flood Warning | PHI | Delaware | 3 hr |
Nearby
Areal Flood Warnings in Pennsylvania, 2021Every areal flood warning in 2021
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.