Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 298, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 8, 2021, 11:27 PM EDT for Hunterdon County, Warren County, New Jersey; Bucks County, Lehigh County, Northampton County, Pennsylvania. It was in force for 48 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 8, 2021, 11:27 PM EDT (03:27 UTC)
- Expired
- Sep 9, 2021, 12:15 AM EDT
- In force
- 48 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Hunterdon County, NJ, Warren County, NJ, Bucks County, PA, Lehigh County, PA, Northampton County, PA
The radar
The Philadelphia radar (KDIX), 103 km from the middle of the area, began a volume at 03:31 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 watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Sep 8, 7:54 PM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
The nearest sounding before it
Brookhaven, NY (KOKX), launched 00:00Z, 3.5 hours before the alert went out and 196 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.
652
WUUS51 KPHI 090327
SVRPHI
NJC019-041-PAC017-077-095-090415-
/O.NEW.KPHI.SV.W.0298.210909T0327Z-210909T0415Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
1127 PM EDT Wed Sep 8 2021
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
Northwestern Hunterdon County in northwestern New Jersey...
Southwestern Warren County in northwestern New Jersey...
Southeastern Lehigh County in eastern Pennsylvania...
Northwestern Bucks County in southeastern Pennsylvania...
Southeastern Northampton County in eastern Pennsylvania...
* Until 1215 AM EDT.
* At 1127 PM EDT, severe thunderstorms were located along a line
extending from near Bath to near Zionsville, moving northeast at 35
mph.
HAZARD...60 mph wind gusts and penny size hail.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
* Locations impacted include...
Allentown, Easton, Bethlehem, Forks, Wilson, Hellertown, Nazareth,
Bath, Harmony, Oxford, Alpha, Ferndale, Frenchtown, West Easton,
Milford, Tatamy, Bloomsbury, Riegelsville, Steuben and Glendon.
This includes the following highways...
Northeast Extension between mile markers 45 and 47.
Interstate 78 in Pennsylvania between mile markers 61 and 76.
Interstate 78 in New Jersey between mile markers 0 and 10.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4081 7499 4051 7504 4043 7548 4075 7540
TIME...MOT...LOC 0327Z 247DEG 29KT 4070 7541 4046 7547
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
JEO2 follow-up statements
577
WWUS51 KPHI 090350
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
1150 PM EDT Wed Sep 8 2021
PAC077-090400-
/O.CAN.KPHI.SV.W.0298.000000T0000Z-210909T0415Z/
Lehigh PA-
1150 PM EDT Wed Sep 8 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN LEHIGH COUNTY IS
CANCELLED...
The storms which prompted the warning have moved out of the warned
area. Therefore, the warning has been cancelled.
A Severe Thunderstorm Watch remains in effect until midnight EDT for
northwestern New Jersey...and eastern and southeastern Pennsylvania.
LAT...LON 4051 7504 4044 7541 4052 7537 4054 7534
4055 7535 4060 7531 4070 7529 4076 7535
4081 7499
TIME...MOT...LOC 0350Z 247DEG 29KT 4077 7519 4053 7525
$$
NJC019-041-PAC017-095-090415-
/O.CON.KPHI.SV.W.0298.000000T0000Z-210909T0415Z/
Hunterdon NJ-Warren NJ-Bucks PA-Northampton PA-
1150 PM EDT Wed Sep 8 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1215 AM EDT
FOR NORTHWESTERN HUNTERDON...SOUTHWESTERN WARREN...NORTHWESTERN BUCKS
AND SOUTHEASTERN NORTHAMPTON COUNTIES...
At 1150 PM EDT, severe thunderstorms were located along a line
extending from near Harmony to near Pleasant Valley, moving northeast
at 35 mph.
HAZARD...60 mph wind gusts and penny size hail.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
Locations impacted include...
Easton, Forks, Wilson, Hellertown, Nazareth, Harmony, Oxford, Alpha,
Ferndale, Belfast, Frenchtown, West Easton, Milford, Tatamy,
Bloomsbury, Riegelsville, Glendon, Brass Castle, Revere and Pleasant
Valley.
This includes the following highways...
Interstate 78 in Pennsylvania between mile markers 70 and 76.
Interstate 78 in New Jersey between mile markers 0 and 10.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4051 7504 4044 7541 4052 7537 4054 7534
4055 7535 4060 7531 4070 7529 4076 7535
4081 7499
TIME...MOT...LOC 0350Z 247DEG 29KT 4077 7519 4053 7525
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
JEO014
WWUS51 KPHI 090406
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
1206 AM EDT Thu Sep 9 2021
NJC019-041-PAC017-095-090415-
/O.EXP.KPHI.SV.W.0298.000000T0000Z-210909T0415Z/
Hunterdon NJ-Warren NJ-Bucks PA-Northampton PA-
1206 AM EDT Thu Sep 9 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN HUNTERDON...
SOUTHWESTERN WARREN...NORTHWESTERN BUCKS AND SOUTHEASTERN NORTHAMPTON
COUNTIES WILL EXPIRE AT 1215 AM EDT...
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire. However gusty
winds are still possible with these thunderstorms.
LAT...LON 4051 7504 4044 7541 4052 7537 4054 7534
4055 7535 4060 7531 4070 7529 4076 7535
4081 7499
TIME...MOT...LOC 0405Z 247DEG 29KT 4082 7504 4058 7510
$$
SFJThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 8, 9:16 PM EDT | Areal Flood Advisory | PHI | Warren | 3 hr |
| Sep 8, 9:16 PM EDT | Special Weather Statement | PHI | Sussex, Warren | 29 min |
| Sep 8, 9:43 PM EDT | Special Weather Statement | PHI | Sussex, Warren | 47 min |
| Sep 8, 10:42 PM EDT | Flash Flood Warning | PHI | Warren | 6 hr |
| Sep 8, 10:56 PM EDT | Special Weather Statement | PHI | Warren | 34 min |
| Sep 8, 11:30 PM EDT | Areal Flood Advisory | PHI | Morris, Sussex | 4 hr |
| Sep 9, 12:07 AM EDT | Special Weather Statement | PHI | Hunterdon, Somerset, Warren | 23 min |
| Sep 9, 12:18 AM EDT | Special Marine Warning | PHI | 57 min | |
| Sep 9, 12:30 AM EDT | Special Weather Statement | PHI | Morris | 30 min |
| Sep 9, 12:41 AM EDT | Special Marine Warning | PHI | 52 min | |
| Sep 9, 2:17 AM EDT | Special Weather Statement | PHI | Ocean | 28 min |
| Sep 9, 2:46 AM EDT | Special Weather Statement | PHI | Atlantic | 29 min |
| Sep 9, 3:14 AM EDT | Special Weather Statement | PHI | Atlantic | 31 min |
| Sep 9, 3:30 AM EDT | Areal Flood Advisory | PHI | Atlantic, Burlington, Cape May, Cumberland | 112 min |
| Sep 9, 4:28 AM EDT | Areal Flood Warning | PHI | Warren | 4 hr |
| 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, 9:38 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, 10:47 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, 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 |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 2021Severe Thunderstorm Warnings in New Jersey, 2021Every severe thunderstorm 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.