Alert archive / Pennsylvania / Flash Flood Warnings in 2021
Flash Flood Warning 80, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 8, 2021, 9:48 PM EDT for Lehigh County, Northampton County, Pennsylvania. It was in force for 7 hr. 2 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Sep 8, 2021, 9:48 PM EDT (01:48 UTC)
- Expired
- Sep 9, 2021, 4:30 AM EDT
- In force
- 7 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), 129 km from the middle of the area, began a volume at 01:49 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Sep 8, 10:20 PM EDT | FLASH FLOOD | Laurys Station, PA | PA ROUTE 145 CLOSED SOUTH OF LAURYS STATION DUE TO FLOODING. |
| Sep 9, 1:00 AM EDT | FLASH FLOOD | 1 Ese Lehigh Valley Int, PA | WATER RESCUE AFTER A CAR STALLED OUT WITH 10 INCHES OF WATER OVER THE ROADWAY. TIME ESTIMATED. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Brookhaven, NY (KOKX), launched 00:00Z, 1.8 hours before the alert went out and 232 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
- 619 J/kg
- Mixed-layer CIN
- -36 J/kg
- Mixed-layer LCL
- 807 m above ground
- 0-6 km bulk shear
- 33 kt
- 0-1 km storm-relative helicity
- 211 m²/s²
- 0-3 km storm-relative helicity
- 225 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 3.4
The text
As transmitted.
931
WGUS51 KPHI 090148
FFWPHI
PAC077-095-090545-
/O.NEW.KPHI.FF.W.0080.210909T0148Z-210909T0545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
948 PM EDT Wed Sep 8 2021
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Central Lehigh County in eastern Pennsylvania...
West Central Northampton County in eastern Pennsylvania...
* Until 145 AM EDT.
* At 948 PM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 2 inches of rain
have fallen. Additional rainfall amounts of 1 to 2 inches are
possible in the warned area. Flash flooding is ongoing or expected
to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets, and underpasses as well as other
drainage and low lying areas.
* Some locations that may experience flash 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 68.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 4065 7585 4083 7539 4070 7527 4052 7565
FLASH FLOOD...RADAR INDICATED
$$
Kruzdlo3 follow-up statements
536
WGUS51 KPHI 090429
FFWPHI
PAC077-095-090830-
/O.EXT.KPHI.FF.W.0080.000000T0000Z-210909T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1229 AM EDT Thu Sep 9 2021
The National Weather Service in Mount Holly has extended the
* Flash Flood Warning for...
Central Lehigh County in eastern Pennsylvania...
West Central Northampton County in eastern Pennsylvania...
* Until 430 AM EDT.
* At 1229 AM EDT, Doppler radar indicated that thunderstorms
produced heavy rain across the warned area. Between 2 and 4 inches
of rain have fallen. Additional rainfall amounts up to 0.5 inches
are possible. Flash flooding is ongoing or expected to begin
shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets, and underpasses as well as other
drainage and low lying areas.
* Some locations that may experience flash flooding include...
Allentown, Bethlehem, Northampton, Nazareth, Slatington, Bath,
Walnutport, Steuben, Coffeetown, Neffs, Schnecksville, and
Beersville.
This includes the following highways...
Interstate 78 in Pennsylvania between mile markers 45 and 55.
Northeast Extension between mile markers 56 and 67.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Motorists should not attempt to drive around barricades or drive
cars through flooded areas.
&&
LAT...LON 4065 7585 4083 7539 4070 7527 4052 7565
FLASH FLOOD...RADAR INDICATED
$$
Iovino571
WGUS71 KPHI 090609
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
209 AM EDT Thu Sep 9 2021
PAC077-095-090830-
/O.CON.KPHI.FF.W.0080.000000T0000Z-210909T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lehigh PA-Northampton PA-
209 AM EDT Thu Sep 9 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 430 AM EDT EARLY THIS
MORNING FOR CENTRAL LEHIGH AND WEST CENTRAL NORTHAMPTON COUNTIES...
At 209 AM EDT, trained weather spotters flash flooding at the Jordan
Creek in North Catasauqua. Between 2 and 4 inches of rain have
fallen. Additional rainfall amounts up to 0.5 inches are possible in
the warned area. Flash flooding is already occurring.
HAZARD...Flash flooding caused by heavy rain.
SOURCE...Trained spotters reported.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets, and underpasses as well as other
drainage and low lying areas.
Some locations that may experience flash 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.
Although the heaviest rain has moved out of the warned area, it will
take time for runoff to recede and any additional rain, even light
rain, will exacerbate flooding that is already ongoing.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 4065 7585 4083 7539 4070 7527 4052 7565
FLASH FLOOD...OBSERVED
$$
SFJ461 WGUS71 KPHI 090826 FFSPHI Flash Flood Statement National Weather Service Mount Holly NJ 426 AM EDT Thu Sep 9 2021 PAC077-095-090836- /O.EXP.KPHI.FF.W.0080.000000T0000Z-210909T0830Z/ /00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/ Lehigh PA-Northampton PA- 426 AM EDT Thu Sep 9 2021 ...FLASH FLOOD WARNING AT 430 AM EDT EARLY THIS MORNING FOR CENTRAL LEHIGH AND WEST CENTRAL NORTHAMPTON COUNTIES HAS BEEN REPLACED WITH A FLOOD WARNING... LAT...LON 4065 7585 4083 7539 4070 7527 4052 7565 $$ SFJ
The 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, 9:59 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, 4:26 AM EDT | Areal Flood Warning | PHI | Lehigh, Northampton | 3 hr |
| Sep 9, 4:28 AM EDT | Areal Flood Warning | PHI | Northampton | 4 hr |
Nearby
Flash Flood Warnings in Pennsylvania, 2021Every flash 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.