Alert archive / Pennsylvania / Areal Flood Warnings in 2021
Areal Flood Warning 47, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this areal flood warning at Sep 9, 2021, 4:26 AM EDT for Lehigh County, Northampton 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
- Sep 9, 2021, 4:26 AM EDT (08:26 UTC)
- Expired
- Sep 9, 2021, 7:30 AM EDT
- In force
- 3 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Lehigh County, PA, Northampton County, PA
The radar
The Philadelphia radar (KDIX), 132 km from the middle of the area, began a volume at 08:28 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, 8.4 hours before the alert went out and 235 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
- 1652 J/kg
- Mixed-layer CIN
- -18 J/kg
- Mixed-layer LCL
- 1146 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km storm-relative helicity
- 115 m²/s²
- 0-3 km storm-relative helicity
- 136 m²/s²
- Significant tornado parameter
- 1.0
- Supercell composite
- 7.0
The text
As transmitted.
460
WGUS41 KPHI 090826
FLWPHI
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
426 AM EDT Thu Sep 9 2021
PAC077-095-091130-
/O.NEW.KPHI.FA.W.0047.210909T0826Z-210909T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lehigh PA-Northampton PA-
426 AM EDT Thu Sep 9 2021
The National Weather Service in Mount Holly has issued a
* Flood Warning for...
Central Lehigh County in eastern Pennsylvania...
West Central Northampton County in eastern Pennsylvania...
* Until 730 AM EDT.
* At 426 AM EDT, local law enforcement reported road flooding across
portions of Lehigh and Northampton Counties. Between 2 and 4
inches of rain fell with thunderstorms Wednesday evening.
* Some locations that may experience flooding include...
Allentown, Bethlehem, Northampton, Nazareth, Slatington, Bath,
Walnutport, Steuben, Coffeetown, Neffs, Schnecksville, and
Beersville.
This includes the following highways...
Interstate 78 in Pennsylvania between mile markers 45 and 55.
Northeast Extension between mile markers 56 and 67.
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 4065 7585 4083 7539 4070 7527 4052 7565
4053 7566 4054 7567 4055 7570 4058 7574
4059 7575 4060 7577 4061 7579 4062 7580
4062 7581 4064 7583
$$
SFJ1 follow-up statement
317
WGUS81 KPHI 091132
FLSPHI
Flood Statement
National Weather Service Mount Holly NJ
732 AM EDT Thu Sep 9 2021
PAC077-095-091142-
/O.EXP.KPHI.FA.W.0047.000000T0000Z-210909T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lehigh PA-Northampton PA-
732 AM EDT Thu Sep 9 2021
...FLOOD WARNING HAS EXPIRED FOR CENTRAL LEHIGH AND WEST CENTRAL
NORTHAMPTON COUNTIES...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
LAT...LON 4065 7585 4083 7539 4070 7527 4052 7565
4053 7566 4054 7567 4055 7570 4058 7574
4059 7575 4060 7577 4061 7579 4062 7580
4062 7581 4064 7583
$$
RobertsonThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 8, 8:47 PM EDT | Special Weather Statement | PHI | Northampton | 28 min |
| Sep 8, 9:12 PM EDT | Special Weather Statement | PHI | Lehigh | 48 min |
| Sep 8, 9:16 PM EDT | Areal Flood Advisory | PHI | Lehigh, Northampton | 3 hr |
| Sep 8, 9:16 PM EDT | Special Weather Statement | PHI | Northampton | 29 min |
| Sep 8, 9:38 PM EDT | Special Weather Statement | PHI | Berks | 52 min |
| Sep 8, 9:46 PM EDT | Special Weather Statement | PHI | Lehigh, Northampton | 44 min |
| Sep 8, 9:48 PM EDT | Flash Flood Warning | PHI | Lehigh, Northampton | 7 hr |
| Sep 8, 9:59 PM EDT | Areal Flood Advisory | PHI | Berks | 3 hr |
| Sep 8, 10:11 PM EDT | Severe Thunderstorm Warning | PHI | Berks | 49 min |
| Sep 8, 10:23 PM EDT | Tornado Warning | PHI | Berks | 22 min |
| Sep 8, 10:27 PM EDT | Special Weather Statement | PHI | Northampton | 33 min |
| Sep 8, 10:42 PM EDT | Flash Flood Warning | PHI | Northampton | 6 hr |
| Sep 8, 10:47 PM EDT | Areal Flood Advisory | PHI | Carbon, Monroe | 3 hr |
| Sep 8, 10:47 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Lehigh, Montgomery, Northampton | 58 min |
| Sep 8, 10:56 PM EDT | Special Weather Statement | PHI | Northampton | 34 min |
| Sep 8, 11:27 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Lehigh, Northampton | 48 min |
| Sep 8, 11:35 PM EDT | Special Weather Statement | PHI | Chester, Delaware, Montgomery | 40 min |
| Sep 9, 12:08 AM EDT | Special Weather Statement | PHI | Bucks, Delaware, Montgomery, Philadelphia | 37 min |
| Sep 9, 4:28 AM EDT | Areal Flood Warning | PHI | Northampton | 4 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.