Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2018
Severe Thunderstorm Warning 70, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 11, 2018, 1:51 PM EDT for Burlington County, Camden County, New Jersey; 5 counties in Pennsylvania. It was in force for 39 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
- Aug 11, 2018, 1:51 PM EDT (17:51 UTC)
- Expired
- Aug 11, 2018, 2:30 PM EDT
- In force
- 39 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Burlington County, NJ, Camden County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 66 km from the middle of the area, began a volume at 17:52 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
Brookhaven, NY (KOKX), launched 12:00Z, 5.9 hours before the alert went out and 215 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
- 840 J/kg
- Mixed-layer CIN
- -19 J/kg
- Mixed-layer LCL
- 590 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 31 m²/s²
- 0-3 km storm-relative helicity
- 76 m²/s²
- Significant tornado parameter
- 0.3
- Supercell composite
- 1.9
The text
As transmitted.
691
WUUS51 KPHI 111751
SVRPHI
NJC005-007-PAC017-029-045-091-101-111830-
/O.NEW.KPHI.SV.W.0070.180811T1751Z-180811T1830Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
151 PM EDT SAT AUG 11 2018
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
Northwestern Camden County in southern New Jersey...
Northwestern Burlington County in southern New Jersey...
Southeastern Montgomery County in southeastern Pennsylvania...
South central Bucks County in southeastern Pennsylvania...
East central Chester County in southeastern Pennsylvania...
Philadelphia County in southeastern Pennsylvania...
Delaware County in southeastern Pennsylvania...
* Until 230 PM EDT.
* At 150 PM EDT, a severe thunderstorm was located over Broomall, or
11 miles west of Philadelphia, moving northeast at 25 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
* Locations impacted include...
Philadelphia, Camden, Gloucester City, Bensalem, Norristown,
Chester, Willingboro, Lansdale, West Norriton, East Norriton,
Yeadon, Burlington, Bristol, Riverside, Conshohocken, Palmyra,
Hatboro, Folcroft, Ambler and Swarthmore.
People attending Philly Free Streets should seek safe shelter
immediately!
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
In addition to damaging winds, frequent cloud to ground lightning is
occurring with this storm. Move indoors immediately. Remember, if
you can hear thunder, you are close enough to be struck by lightning.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 3984 7539 3996 7548 4014 7542 4023 7529
4029 7501 4023 7492 4004 7484 3995 7486
TIME...MOT...LOC 1750Z 242DEG 22KT 3997 7534
HAIL...<.75IN
WIND...60MPH
$$
JRK2 follow-up statements
072
WWUS51 KPHI 111809
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
209 PM EDT SAT AUG 11 2018
PAC029-111819-
/O.CAN.KPHI.SV.W.0070.000000T0000Z-180811T1830Z/
Chester PA-
209 PM EDT SAT AUG 11 2018
...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL CHESTER COUNTY IS
CANCELLED...
The storms which prompted the warning have moved out of the warned
area. Therefore, the warning has been cancelled.
LAT...LON 4010 7486 4007 7490 3994 7491 3984 7539
3993 7546 3999 7542 4011 7530 4024 7525
4029 7501 4023 7492
TIME...MOT...LOC 1809Z 232DEG 25KT 4022 7518 4004 7520 3990 7539
$$
NJC005-007-PAC017-045-091-101-111830-
/O.CON.KPHI.SV.W.0070.000000T0000Z-180811T1830Z/
Camden NJ-Burlington NJ-Montgomery PA-Bucks PA-Philadelphia PA-
Delaware PA-
209 PM EDT SAT AUG 11 2018
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 230 PM EDT
FOR NORTHWESTERN CAMDEN...NORTHWESTERN BURLINGTON...SOUTHEASTERN
MONTGOMERY...SOUTH CENTRAL BUCKS...PHILADELPHIA AND EASTERN DELAWARE
COUNTIES...
At 209 PM EDT, severe thunderstorms were located along a line
extending from near Ambler to Germantown to Nether Providence
Township, moving northeast at 30 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
Locations impacted include...
Philadelphia, Camden, Gloucester City, Bensalem, Chester, Yeadon,
Bristol, Riverside, Conshohocken, Palmyra, Hatboro, Folcroft, Ambler,
Swarthmore, Jenkintown, Narberth, East Lansdowne, Beverly, Rockledge
and Newtown.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
In addition to damaging winds, frequent cloud to ground lightning is
occurring with this storm. Move indoors immediately. Remember, if
you can hear thunder, you are close enough to be struck by lightning.
Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4010 7486 4007 7490 3994 7491 3984 7539
3993 7546 3999 7542 4011 7530 4024 7525
4029 7501 4023 7492
TIME...MOT...LOC 1809Z 232DEG 25KT 4022 7518 4004 7520 3990 7539
HAIL...<.75IN
WIND...60MPH
$$
JRK481
WWUS51 KPHI 111823
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
223 PM EDT SAT AUG 11 2018
NJC005-007-PAC017-045-091-101-111833-
/O.EXP.KPHI.SV.W.0070.000000T0000Z-180811T1830Z/
Camden NJ-Burlington NJ-Montgomery PA-Bucks PA-Philadelphia PA-
Delaware PA-
223 PM EDT SAT AUG 11 2018
...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN CAMDEN...
NORTHWESTERN BURLINGTON...SOUTHEASTERN MONTGOMERY...SOUTH CENTRAL
BUCKS...PHILADELPHIA AND EASTERN DELAWARE COUNTIES WILL EXPIRE AT 230
PM EDT...
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire. However gusty
winds and heavy rain are still occurring with these thunderstorms.
LAT...LON 4010 7486 4007 7490 3994 7491 3984 7539
3993 7546 3999 7542 4011 7530 4024 7525
4029 7501 4023 7492
TIME...MOT...LOC 1823Z 242DEG 22KT 4025 7509 4007 7511 3993 7531
$$
JRKThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 11, 3:24 AM EDT | Flash Flood Watch | PHI | Atlantic, Burlington, Camden, Cumberland, Gloucester, Hunterdon and 9 more | 20 hr |
| Aug 11, 4:26 AM EDT | Coastal Flood Advisory | PHI | Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 5 more | 24 hr |
| Aug 11, 5:27 AM EDT | Areal Flood Advisory | PHI | Hunterdon, Morris, Warren | 4 hr |
| Aug 11, 6:06 AM EDT | Areal Flood Advisory | PHI | Hunterdon, Warren | 6 hr |
| Aug 11, 6:31 AM EDT | Areal Flood Advisory | PHI | Hunterdon, Mercer, Middlesex, Morris, Somerset | 7 hr |
| Aug 11, 7:16 AM EDT | Flash Flood Warning | PHI | Middlesex, Somerset | 4 hr |
| Aug 11, 10:49 AM EDT | Areal Flood Advisory | PHI | Middlesex, Somerset | 3 hr |
| Aug 11, 11:29 AM EDT | Areal Flood Advisory | PHI | Atlantic | 4 hr |
| Aug 11, 11:46 AM EDT | Special Marine Warning | PHI | 119 min | |
| Aug 11, 11:55 AM EDT | Special Weather Statement | PHI | Burlington | 35 min |
| Aug 11, 12:27 PM EDT | Areal Flood Advisory | PHI | Burlington, Camden, Gloucester, Ocean | 4 hr |
| Aug 11, 12:39 PM EDT | Special Weather Statement | PHI | Ocean | 36 min |
| Aug 11, 12:55 PM EDT | Special Marine Warning | PHI | 65 min | |
| Aug 11, 1:07 PM EDT | Flash Flood Warning | PHI | Atlantic, Cape May | 4 hr |
| Aug 11, 1:26 PM EDT | Special Marine Warning | PHI | 2 hr | |
| Aug 11, 1:42 PM EDT | Special Marine Warning | PHI | 2 hr | |
| Aug 11, 2:00 PM EDT | Flash Flood Warning | PHI | Warren | 9 hr |
| Aug 11, 2:05 PM EDT | Special Weather Statement | PHI | Cape May | 25 min |
| Aug 11, 2:06 PM EDT | Areal Flood Advisory | PHI | Burlington, Camden, Gloucester | 3 hr |
| Aug 11, 2:19 PM EDT | Special Marine Warning | PHI | 86 min | |
| Aug 11, 2:20 PM EDT | Areal Flood Advisory | PHI | Cape May, Cumberland | 3 hr |
| Aug 11, 2:30 PM EDT | Flash Flood Warning | PHI | Hunterdon, Morris, Warren | 3 hr |
| Aug 11, 2:46 PM EDT | Flash Flood Warning | PHI | Hunterdon, Mercer, Middlesex, Morris, Somerset | 3 hr |
| Aug 11, 2:58 PM EDT | Special Weather Statement | PHI | Cumberland | 47 min |
| Aug 11, 3:06 PM EDT | Flash Flood Warning | PHI | Warren | 4 hr |
| Aug 11, 3:13 PM EDT | Special Weather Statement | PHI | Hunterdon | 47 min |
| Aug 11, 3:23 PM EDT | Areal Flood Advisory | PHI | Morris, Sussex | 3 hr |
| Aug 11, 3:24 PM EDT | Special Weather Statement | PHI | Atlantic, Cumberland | 51 min |
| Aug 11, 3:32 PM EDT | Flash Flood Warning | PHI | Atlantic | 3 hr |
| Aug 11, 3:47 PM EDT | Flash Flood Warning | PHI | Morris | 3 hr |
| Aug 11, 4:11 PM EDT | Special Marine Warning | PHI | 2 hr | |
| Aug 11, 4:28 PM EDT | Special Marine Warning | PHI | 2 hr | |
| Aug 11, 5:00 PM EDT | Areal Flood Advisory | PHI | Gloucester, Salem | 3 hr |
| Aug 11, 5:26 PM EDT | Areal Flood Advisory | PHI | Hunterdon, Morris, Warren | 4 hr |
| Aug 11, 5:36 PM EDT | Areal Flood Warning | PHI | Hunterdon, Mercer, Middlesex, Morris, Somerset | 4 hr |
| Aug 11, 6:11 PM EDT | Special Marine Warning | PHI | 2 hr | |
| Aug 11, 6:12 PM EDT | Flash Flood Warning | PHI | Salem | 3 hr |
| Aug 11, 7:35 PM EDT | Areal Flood Advisory | PHI | Atlantic, Cumberland | 3 hr |
| Aug 11, 7:46 PM EDT | River Flood Warning | PHI | Essex, Morris, Passaic | 4 days |
| Aug 11, 2:25 AM EDT | Special Weather Statement | PHI | Berks | 65 min |
| Aug 11, 3:26 AM EDT | Special Weather Statement | PHI | Berks | 64 min |
| Aug 11, 4:17 AM EDT | Areal Flood Advisory | PHI | Berks | 4 hr |
| Aug 11, 5:19 AM EDT | Flash Flood Warning | PHI | Berks | 3 hr |
| Aug 11, 12:16 PM EDT | Special Weather Statement | PHI | Chester | 29 min |
| Aug 11, 12:48 PM EDT | Areal Flood Advisory | PHI | Chester | 3 hr |
| Aug 11, 1:20 PM EDT | Areal Flood Advisory | PHI | Chester, Montgomery | 3 hr |
| Aug 11, 1:33 PM EDT | Flash Flood Warning | PHI | Chester, Montgomery | 4 hr |
| Aug 11, 1:40 PM EDT | Flash Flood Warning | PHI | Chester | 4 hr |
| Aug 11, 1:48 PM EDT | Flash Flood Warning | PHI | Delaware, Philadelphia | 4 hr |
| Aug 11, 2:14 PM EDT | Flash Flood Warning | PHI | Bucks | 3 hr |
| Aug 11, 2:26 PM EDT | Special Weather Statement | PHI | Bucks, Philadelphia | 34 min |
| Aug 11, 2:42 PM EDT | Special Weather Statement | PHI | Bucks | 33 min |
| Aug 11, 3:50 PM EDT | Areal Flood Advisory | PHI | Berks, Montgomery | 115 min |
| Aug 11, 4:19 PM EDT | Areal Flood Advisory | PHI | Chester | 3 hr |
| Aug 11, 4:19 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 29 min |
| Aug 11, 4:47 PM EDT | Special Weather Statement | PHI | Montgomery | 28 min |
| Aug 11, 4:52 PM EDT | Areal Flood Advisory | PHI | Carbon, Lehigh | 2 hr |
| Aug 11, 5:58 PM EDT | Areal Flood Advisory | PHI | Chester, Delaware, Montgomery, Philadelphia | 5 hr |
| Aug 11, 6:13 PM EDT | Special Weather Statement | PHI | Chester | 32 min |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 2018Severe Thunderstorm Warnings in New Jersey, 2018Every severe thunderstorm warning in 2018
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.