Alert archive / Pennsylvania / Areal Flood Advisories in 2021
Areal Flood Advisory 98, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this areal flood advisory at Jul 29, 2021, 4:46 PM EDT for Berks County, Lehigh County, Northampton County, Pennsylvania. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 29, 2021, 4:46 PM EDT (20:46 UTC)
- Expired
- Jul 29, 2021, 7:32 PM EDT
- In force
- 3 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
Counties Berks County, PA, Lehigh County, PA, Northampton County, PA
The radar
The Philadelphia radar (KDIX), 139 km from the middle of the area, began a volume at 20:45 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, 8.8 hours before the alert went out and 241 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
- 269 J/kg
- Mixed-layer CIN
- -91 J/kg
- Mixed-layer LCL
- 893 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 62 m²/s²
- 0-3 km storm-relative helicity
- 62 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
The text
As transmitted.
742
WGUS81 KPHI 292046
FLSPHI
Flood Advisory
National Weather Service Mount Holly NJ
446 PM EDT Thu Jul 29 2021
PAC011-077-095-292345-
/O.NEW.KPHI.FA.Y.0098.210729T2046Z-210729T2345Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-Lehigh PA-Northampton PA-
446 PM EDT Thu Jul 29 2021
The National Weather Service in Mount Holly has issued a
* Flood Advisory for...
North Central Berks County in eastern Pennsylvania...
Lehigh County in eastern Pennsylvania...
Southwestern Northampton County in eastern Pennsylvania...
* Until 745 PM EDT.
* At 446 PM EDT, Doppler radar indicated heavy rain due to
thunderstorms. Minor flooding is ongoing or expected to begin
shortly in the advisory area. Between 1 and 2 inches of rain have
fallen.
* Some locations that will experience flooding include...
Allentown, Bethlehem, Northampton, Slatington, Walnutport,
Schnecksville, Neffs, Coffeetown, Emerald, Claussville,
Berlinsville, and Jordan Valley.
This includes the following highways...
Northeast Extension between mile markers 58 and 70.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Be aware of your surroundings and do not drive on flooded roads.
Flooding is occurring or is imminent. It is important to know where
you are relative to streams, rivers, or creeks which can become
killers in heavy rains. Campers and hikers should avoid streams or
creeks.
Please report observed flooding to local emergency services or law
enforcement and request they pass this information to the National
Weather Service when you can do so safely.
&&
LAT...LON 4068 7589 4071 7581 4073 7578 4076 7571
4082 7546 4059 7536 4059 7588
$$
MPS2 follow-up statements
357
WGUS81 KPHI 292200
FLSPHI
Flood Advisory
National Weather Service Mount Holly NJ
600 PM EDT Thu Jul 29 2021
PAC011-077-095-292345-
/O.CON.KPHI.FA.Y.0098.000000T0000Z-210729T2345Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-Lehigh PA-Northampton PA-
600 PM EDT Thu Jul 29 2021
...FLOOD ADVISORY REMAINS IN EFFECT UNTIL 745 PM EDT THIS EVENING
FOR NORTH CENTRAL BERKS, LEHIGH, AND SOUTHWESTERN NORTHAMPTON
COUNTIES...
At 600 PM EDT, Doppler radar indicated heavy rain due to
thunderstorms has moved out of the advisory area. Between 1 and 2
inches of rain have fallen. Minor flooding is ongoing in the
advisory area.
Some locations that will experience flooding include...
Allentown, Bethlehem, Northampton, Slatington, Walnutport,
Schnecksville, Neffs, Coffeetown, Emerald, Claussville,
Berlinsville, and Jordan Valley.
This includes the following highways...
Interstate 78 in Pennsylvania near mile marker 66.
Northeast Extension between mile markers 58 and 70.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Be aware of your surroundings and do not drive on flooded roads.
Please report observed flooding to local emergency services or law
enforcement and request they pass this information to the National
Weather Service when you can do so safely.
&&
LAT...LON 4068 7589 4071 7581 4073 7578 4076 7571
4082 7546 4059 7536 4059 7588
$$
MPS351
WGUS81 KPHI 292332
FLSPHI
Flood Advisory
National Weather Service Mount Holly NJ
732 PM EDT Thu Jul 29 2021
PAC011-077-095-292342-
/O.CAN.KPHI.FA.Y.0098.000000T0000Z-210729T2345Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-Lehigh PA-Northampton PA-
732 PM EDT Thu Jul 29 2021
...FLOOD ADVISORY IS CANCELLED FOR NORTH CENTRAL BERKS, LEHIGH, AND
SOUTHWESTERN NORTHAMPTON 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 4068 7589 4071 7581 4073 7578 4076 7571
4082 7546 4059 7536 4059 7588
$$
MPSThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 29, 3:48 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Lehigh, Northampton | 42 min |
| Jul 29, 4:03 PM EDT | Tornado Warning | PHI | Berks, Lehigh, Northampton | 27 min |
| Jul 29, 4:27 PM EDT | Tornado Warning | PHI | Lehigh, Northampton | 16 min |
| Jul 29, 4:30 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Bucks, Carbon, Lehigh, Monroe, Northampton | 45 min |
| Jul 29, 4:56 PM EDT | Tornado Warning | PHI | Bucks, Lehigh, Northampton | 34 min |
| Jul 29, 4:57 PM EDT | Areal Flood Advisory | PHI | Bucks, Monroe, Northampton | 3 hr |
| Jul 29, 5:03 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Lehigh, Monroe, Northampton | 42 min |
| Jul 29, 5:08 PM EDT | Tornado Warning | PHI | Bucks | 37 min |
| Jul 29, 5:27 PM EDT | Areal Flood Advisory | PHI | Bucks | 3 hr |
| Jul 29, 5:32 PM EDT | Flash Flood Warning | PHI | Northampton | 2 hr |
| Jul 29, 5:32 PM EDT | Tornado Warning | PHI | Bucks | 28 min |
| Jul 29, 5:51 PM EDT | Tornado Warning | PHI | Bucks | 24 min |
| Jul 29, 5:58 PM EDT | Flash Flood Warning | PHI | Bucks | 3 hr |
| Jul 29, 6:06 PM EDT | Tornado Warning | PHI | Bucks | 39 min |
| Jul 29, 6:21 PM EDT | Special Weather Statement | PHI | Bucks | 24 min |
| Jul 29, 6:45 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery, Philadelphia | 45 min |
| Jul 29, 7:07 PM EDT | Tornado Warning | PHI | Bucks, Philadelphia | 23 min |
| Jul 29, 7:12 PM EDT | Flash Flood Warning | PHI | Bucks, Philadelphia | 4 hr |
| Jul 29, 7:25 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 50 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.