Alert archive / Pennsylvania / Areal Flood Warnings in 2021
Areal Flood Warning 50, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this areal flood warning at Sep 23, 2021, 4:26 PM EDT for 4 counties in Pennsylvania. It was in force for 80 min. 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 23, 2021, 4:26 PM EDT (20:26 UTC)
- Expired
- Sep 23, 2021, 5:46 PM EDT
- In force
- 80 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 82 km from the middle of the area, began a volume at 20:27 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
Washington/Dulle, VA (KIAD), launched 12:00Z, 8.4 hours before the alert went out and 209 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
- 517 m above ground
- 0-6 km bulk shear
- 58 kt
- 0-1 km storm-relative helicity
- -71 m²/s²
- 0-3 km storm-relative helicity
- 88 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.0
The text
As transmitted.
246
WGUS41 KPHI 232026
FLWPHI
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
426 PM EDT Thu Sep 23 2021
PAC029-045-091-101-232230-
/O.NEW.KPHI.FA.W.0050.210923T2026Z-210923T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-Delaware PA-Montgomery PA-Philadelphia PA-
426 PM EDT Thu Sep 23 2021
The National Weather Service in Mount Holly has issued a
* Flood Warning for...
Northeastern Chester County in southeastern Pennsylvania...
Eastern Delaware County in southeastern Pennsylvania...
Central Montgomery County in southeastern Pennsylvania...
Western Philadelphia County in southeastern Pennsylvania...
* Until 630 PM EDT.
* At 426 PM EDT, Doppler radar indicated heavy rain due to
thunderstorms. Flooding is ongoing or expected to begin shortly in
Delaware county. Between 1.5 and 3 inches of rain have fallen.
* Some locations that may experience flooding include...
Philadelphia, Norristown, Chester, Phoenixville, West Norriton,
East Norriton, Yeadon, Conshohocken, Folcroft, Swarthmore,
Collegeville, and Royersford.
This includes the following highways...
Pennsylvania Turnpike between mile markers 317 and 336.
Interstate 95 in Pennsylvania between mile markers 7 and 16.
Interstate 76 in Pennsylvania between mile markers 327 and 350.
Interstate 676 in Pennsylvania near mile marker 0.
Interstate 476 in Pennsylvania between mile markers 0 and 19.
Northeast Extension between mile markers 21 and 30.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
Motorists should not attempt to drive around barricades or drive
cars through flooded areas.
&&
LAT...LON 4024 7560 4031 7553 4025 7533 4016 7524
3992 7515 3986 7521 3986 7522 3986 7523
3985 7529 3985 7531 3985 7532 3985 7533
3985 7534 3984 7535 3986 7535 4018 7571
4019 7565
$$
NC1 follow-up statement
039
WGUS81 KPHI 232146
FLSPHI
Flood Statement
National Weather Service Mount Holly NJ
546 PM EDT Thu Sep 23 2021
PAC029-045-091-101-232156-
/O.CAN.KPHI.FA.W.0050.000000T0000Z-210923T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-Delaware PA-Montgomery PA-Philadelphia PA-
546 PM EDT Thu Sep 23 2021
...FLOOD WARNING IS CANCELLED FOR NORTHEASTERN CHESTER, EASTERN
DELAWARE, CENTRAL MONTGOMERY, AND WESTERN PHILADELPHIA COUNTIES...
Flood waters have receded. The heavy rain has ended. Flooding is no
longer expected to pose a threat. Please continue to heed remaining
road closures.
LAT...LON 4024 7560 4031 7553 4025 7533 4016 7524
3992 7515 3986 7521 3986 7522 3986 7523
3985 7529 3985 7531 3985 7532 3985 7533
3985 7534 3984 7535 3986 7535 4018 7571
4019 7565
$$
NCThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 23, 9:12 AM EDT | Coastal Flood Advisory | PHI | Bucks, Delaware, Philadelphia | 10 hr |
| Sep 23, 10:52 AM EDT | Areal Flood Advisory | PHI | Chester | 3 hr |
| Sep 23, 11:33 AM EDT | Areal Flood Advisory | PHI | Berks, Chester, Delaware, Montgomery, Philadelphia | 3 hr |
| Sep 23, 11:40 AM EDT | Areal Flood Advisory | PHI | Berks, Bucks, Carbon, Lehigh, Montgomery, Northampton | 3 hr |
| Sep 23, 11:57 AM EDT | Flash Flood Warning | PHI | Chester, Delaware | 3 hr |
| Sep 23, 12:12 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 48 min |
| Sep 23, 12:28 PM EDT | Flash Flood Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 4 hr |
| Sep 23, 12:54 PM EDT | Special Weather Statement | PHI | Philadelphia | 51 min |
| Sep 23, 12:56 PM EDT | Areal Flood Advisory | PHI | Bucks, Carbon, Lehigh, Monroe, Montgomery, Northampton and 1 more | 3 hr |
| Sep 23, 12:57 PM EDT | Special Weather Statement | PHI | Bucks | 33 min |
| Sep 23, 1:13 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 47 min |
| Sep 23, 1:42 PM EDT | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 4 hr |
| Sep 23, 1:48 PM EDT | River Flood Warning | PHI | Chester | 5 hr |
| Sep 23, 1:58 PM EDT | Special Weather Statement | PHI | Bucks | 32 min |
| Sep 23, 2:37 PM EDT | Areal Flood Advisory | PHI | Bucks, Northampton | 3 hr |
| Sep 23, 3:26 PM EDT | Flash Flood Warning | PHI | Bucks | 2 hr |
| Sep 23, 7:18 PM EDT | Areal Flood Warning | PHI | Berks, Montgomery | 36 min |
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.