Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 40, NWS Philadelphia/Mount Holly

June 24, 20184 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 24, 2018, 7:32 PM EDT for 4 counties in Pennsylvania. It was in force for 28 min. 4 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
Jun 24, 2018, 7:32 PM EDT (23:32 UTC)
Expired
Jun 24, 2018, 8:00 PM EDT
In force
28 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Bucks County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 71 km from the middle of the area, began a volume at 23:34 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

TimeReportWhereRemark
Jun 24, 7:32 PM EDTTSTM WND DMGWhitemarsh Twp, PATREES DOWN. TIME ESTIMATED FROM RADAR.
Jun 24, 7:34 PM EDTTSTM WND DMGPlymouth Meeting, PALARGE TREE LIMBS NEAR OR GREATER THAN A FOOT IN DIAMETER DOWNED IN A RESIDENTIAL AREA. NO SIGNIFICANT DAMAGE APPEARS TO HAVE BEEN CAUSED BY THEM. TIME ESTIMATED FROM RADAR.
Jun 24, 7:45 PM EDTTSTM WND DMGCheltenham, PATREES DOWN IN THE JOHNS ROAD AREA. TIME ESTIMATED FROM RADAR.
Jun 24, 7:52 PM EDTTSTM WND DMGFox Chase, PATREES DOWN IN SEVERAL AREAS OF NORTHEAST PHILADELPHIA. TIME ESTIMATED FROM RADAR.

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 12:00Z, 11.5 hours before the alert went out and 220 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.

Skew-T log-pSkew-T log-p diagram, Brookhaven, NY at 12:00Z on 2018-06-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2018-06-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
538 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
123 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

104 
WUUS51 KPHI 242332
SVRPHI
PAC017-045-091-101-250000-
/O.NEW.KPHI.SV.W.0040.180624T2332Z-180625T0000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
732 PM EDT SUN JUN 24 2018

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southeastern Montgomery County in southeastern Pennsylvania...
  South central Bucks County in southeastern Pennsylvania...
  Philadelphia County in southeastern Pennsylvania...
  Northeastern Delaware County in southeastern Pennsylvania...

* Until 800 PM EDT.

* At 731 PM EDT, a severe thunderstorm was located over Conshohocken,
  or 11 miles northwest of Philadelphia, moving east 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, Bensalem, Norristown, West Norriton, East Norriton,
  Yeadon, Conshohocken, Palmyra, Ambler, Jenkintown, Narberth, East
  Lansdowne, Rockledge, Abington, Bryn Athyn, Wissinoming, Morris
  Park, Bryn Mawr, Trout Lake and Tacony.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4012 7487 3997 7510 3996 7513 3995 7514
      3991 7519 4001 7543 4003 7540 4004 7541
      4007 7536 4006 7539 4008 7541 4020 7532
TIME...MOT...LOC 2331Z 291DEG 27KT 4008 7532 

HAIL...<.75IN
WIND...60MPH
 
$$

MPS
2 follow-up statements
275 
WWUS51 KPHI 242349
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
749 PM EDT SUN JUN 24 2018

PAC045-242358-
/O.CAN.KPHI.SV.W.0040.000000T0000Z-180625T0000Z/
Delaware PA-
749 PM EDT SUN JUN 24 2018

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN DELAWARE COUNTY
IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4012 7487 3997 7510 3996 7513 3995 7514
      3991 7519 4003 7530 4016 7512
TIME...MOT...LOC 2348Z 291DEG 27KT 4003 7516 

$$

PAC017-091-101-250000-
/O.CON.KPHI.SV.W.0040.000000T0000Z-180625T0000Z/
Montgomery PA-Bucks PA-Philadelphia PA-
749 PM EDT SUN JUN 24 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM EDT
FOR SOUTHEASTERN MONTGOMERY...SOUTH CENTRAL BUCKS AND PHILADELPHIA
COUNTIES...

At 748 PM EDT, a severe thunderstorm was located over Germantown, or
over Philadelphia, moving east 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, Bensalem, Palmyra, Jenkintown, Narberth, Rockledge,
Abington, Bryn Athyn, Wissinoming, Willow Grove, Germantown,
Northeast Philadelphia, Center City, Tacony, Andalusia, Holmesburg,
Kensington, Roxborough, Chestnut Hill and Pennsauken.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4012 7487 3997 7510 3996 7513 3995 7514
      3991 7519 4003 7530 4016 7512
TIME...MOT...LOC 2348Z 291DEG 27KT 4003 7516 

HAIL...<.75IN
WIND...60MPH
 
$$

MPS
218 
WWUS51 KPHI 242359
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
759 PM EDT SUN JUN 24 2018

PAC017-091-101-250008-
/O.EXP.KPHI.SV.W.0040.000000T0000Z-180625T0000Z/
Montgomery PA-Bucks PA-Philadelphia PA-
759 PM EDT SUN JUN 24 2018

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN MONTGOMERY...
SOUTH CENTRAL BUCKS AND PHILADELPHIA COUNTIES WILL EXPIRE AT 800 PM
EDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.  However gusty winds and heavy rain are still
possible with this thunderstorm.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
in Mount Holly NJ.

LAT...LON 4012 7487 3997 7510 3996 7513 3995 7514
      3991 7519 4003 7530 4016 7512
TIME...MOT...LOC 2358Z 291DEG 27KT 4001 7508 

$$

MPS

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 24, 5:30 PM EDTSpecial Weather StatementPHIMonroe30 min
Jun 24, 5:59 PM EDTSpecial Weather StatementPHIBerks31 min
Jun 24, 6:04 PM EDTSpecial Weather StatementPHIBerks26 min
Jun 24, 6:14 PM EDTSpecial Weather StatementPHICarbon, Monroe46 min
Jun 24, 6:36 PM EDTSpecial Weather StatementPHIChester, Montgomery39 min
Jun 24, 6:50 PM EDTSpecial Weather StatementPHILehigh, Northampton25 min
Jun 24, 6:52 PM EDTSpecial Weather StatementPHIBerks38 min
Jun 24, 7:08 PM EDTAreal Flood AdvisoryPHIBucks, Chester, Montgomery114 min
Jun 24, 7:10 PM EDTSpecial Weather StatementPHIChester, Delaware, Montgomery50 min
Jun 24, 7:22 PM EDTSpecial Weather StatementPHINorthampton23 min
Jun 24, 7:56 PM EDTSpecial Weather StatementPHIPhiladelphia34 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.