Alert archive / Pennsylvania / Areal Flood Advisories in 2021
Areal Flood Advisory 93, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this areal flood advisory at Jul 17, 2021, 9:15 PM EDT for Delaware County, Montgomery County, Philadelphia County, Pennsylvania. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 17, 2021, 9:15 PM EDT (01:15 UTC)
- Expired
- Jul 17, 2021, 11:39 PM EDT
- In force
- 2 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
Counties Delaware County, PA, Montgomery County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 80 km from the middle of the area, began a volume at 01:18 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 00:00Z, 1.3 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
- 933 J/kg
- Mixed-layer CIN
- -83 J/kg
- Mixed-layer LCL
- 1286 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 163 m²/s²
- 0-3 km storm-relative helicity
- 172 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 1.3
The text
As transmitted.
623
WGUS81 KPHI 180115
FLSPHI
Flood Advisory
National Weather Service Mount Holly NJ
915 PM EDT Sat Jul 17 2021
PAC045-091-101-180400-
/O.NEW.KPHI.FA.Y.0093.210718T0115Z-210718T0400Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Delaware PA-Montgomery PA-Philadelphia PA-
915 PM EDT Sat Jul 17 2021
The National Weather Service in Mount Holly has issued a
* Flood Advisory for...
Delaware County in southeastern Pennsylvania...
Southeastern Montgomery County in southeastern Pennsylvania...
Philadelphia County in southeastern Pennsylvania...
* Until midnight EDT.
* At 915 PM EDT, Doppler radar indicated heavy rain due to
thunderstorms. Minor flooding is ongoing or expected to begin
shortly in the advisory area. Between 0.5 and 1 inch of rain has
already fallen in spots with another 1.0 to 1.5 inches possible.
* Some locations that may experience flooding include...
Philadelphia, Chester, Yeadon, Conshohocken, Palmyra, Hatboro,
Folcroft, Ambler, Swarthmore, Jenkintown, and Narberth.
This includes the following highways...
Pennsylvania Turnpike between mile markers 332 and 346.
Interstate 95 in Pennsylvania between mile markers 0 and 33.
Interstate 76 in Pennsylvania between mile markers 330 and 351.
Interstate 676 in Pennsylvania between mile markers 0 and 1.
Interstate 476 in Pennsylvania between mile markers 0 and 19.
Northeast Extension between mile markers 21 and 22.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Be aware of your surroundings and do not drive on flooded roads.
&&
LAT...LON 4007 7536 4024 7519 4012 7496 4005 7497
3996 7513 3991 7513 3988 7515 3985 7534
3980 7542 3983 7550 3984 7560 3987 7560
3993 7554 3992 7552 3994 7552 3999 7544
3999 7545 4003 7540 4004 7541
$$
Iovino1 follow-up statement
277
WGUS81 KPHI 180339
FLSPHI
Flood Advisory
National Weather Service Mount Holly NJ
1139 PM EDT Sat Jul 17 2021
PAC045-091-101-180349-
/O.CAN.KPHI.FA.Y.0093.000000T0000Z-210718T0400Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Delaware PA-Montgomery PA-Philadelphia PA-
1139 PM EDT Sat Jul 17 2021
...FLOOD ADVISORY IS CANCELLED FOR DELAWARE, SOUTHEASTERN
MONTGOMERY, AND PHILADELPHIA COUNTIES...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
LAT...LON 4007 7536 4024 7519 4012 7496 4005 7497
3996 7513 3991 7513 3988 7515 3985 7534
3980 7542 3983 7550 3984 7560 3987 7560
3993 7554 3992 7552 3994 7552 3999 7544
3999 7545 4003 7540 4004 7541
$$
IovinoThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 17, 8:00 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery, Philadelphia | 45 min |
| Jul 17, 8:09 PM EDT | Flash Flood Warning | PHI | Bucks | 4 hr |
| Jul 17, 8:44 PM EDT | Areal Flood Advisory | PHI | Chester, Montgomery | 82 min |
| Jul 17, 8:57 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 48 min |
| Jul 17, 9:27 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 48 min |
| Jul 17, 9:36 PM EDT | Flash Flood Warning | PHI | Delaware, Montgomery, Philadelphia | 2 hr |
| Jul 17, 9:48 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 42 min |
| Jul 17, 10:21 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 54 min |
Nearby
Areal Flood Advisories in Pennsylvania, 2021Every areal flood advisory 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.