Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 32, NWS Philadelphia/Mount Holly

May 26, 20216 counties in Pennsylvania; Hunterdon County, Mercer County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 26, 2021, 5:27 PM EDT for 6 counties in Pennsylvania; Hunterdon County, Mercer County, New Jersey. It was in force for 48 min. 6 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
May 26, 2021, 5:27 PM EDT (21:27 UTC)
Expired
May 26, 2021, 6:15 PM EDT
In force
48 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
70.0 mph

Counties Hunterdon County, NJ, Mercer County, NJ, Berks County, PA, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 99 km from the middle of the area, began a volume at 21:30 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
May 26, 5:27 PM EDTTSTM WND DMG2 Ssw East Nantmeal Twp, PADOWNED TREE ON BUCK DRIVE NEAR RABBIT RUN LANE. TIME ESTIMATED FROM RADAR.
May 26, 5:27 PM EDTTSTM WND DMGPaoli, PADOWNED WIRES ON WISTAR ROAD NEAR CHETWYND ROAD. TIME ESTIMATED FROM RADAR.
May 26, 5:30 PM EDTTSTM WND DMG1 Ssw Phoenixville, PADOWNED TREE LIMBS ON FOURTH AVENUE AND LINCOLN AVENUE. TIME ESTIMATED FROM RADAR.
May 26, 5:32 PM EDTTSTM WND DMG2 S East Nantmeal Twp, PADOWNED TREE ON STYER ROAD NEAR MEADOW CREEK LANE. TIME ESTIMATED FROM RADAR.
May 26, 5:35 PM EDTHAIL 0.88Bedminster, PATIME ESTIMATED FROM RADAR.
May 26, 5:39 PM EDTTSTM WND DMG1 Ese Hatboro, PADOWNED TREE LIMBS ON DAVISVILLE ROAD AND DANIELLE DRIVE. TIME ESTIMATED FROM RADAR.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 26, 2:48 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.5 hours before the alert went out and 217 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, Washington/Dulle, VA at 12:00Z on 2021-05-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 478 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2021-05-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 35 square meters per square second.193958Sfc1 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
478 J/kg
Mixed-layer CIN
-132 J/kg
Mixed-layer LCL
922 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
35 m²/s²
0-3 km storm-relative helicity
50 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

235 
WUUS51 KPHI 262127
SVRPHI
NJC019-021-PAC011-017-029-045-091-101-262230-
/O.NEW.KPHI.SV.W.0032.210526T2127Z-210526T2230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
527 PM EDT Wed May 26 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southern Hunterdon County in northwestern New Jersey...
  Northwestern Mercer County in central New Jersey...
  Southeastern Berks County in eastern Pennsylvania...
  Montgomery County in southeastern Pennsylvania...
  Bucks County in southeastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...
  Northwestern Philadelphia County in southeastern Pennsylvania...
  Northeastern Delaware County in southeastern Pennsylvania...

* Until 630 PM EDT.

* At 527 PM EDT, severe thunderstorms were located along a line
  extending from Milford to Dublin to Glenmoore, moving east at 30
  mph.

  HAZARD...70 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect considerable tree damage. Damage is likely to 
           mobile homes, roofs, and outbuildings.

* Locations impacted include...
  Philadelphia, Ewing, Norristown, Pottstown, Phoenixville, Lansdale,
  West Norriton, East Norriton, Quakertown, Perkasie, Doylestown,
  Byram, Downingtown, Conshohocken, Hatboro, Souderton, Bedminster,
  Ambler, Collegeville and Royersford.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 298 and 349.
 Northeast Extension between mile markers 21 and 42.
 Interstate 76 in Pennsylvania between mile markers 327 and 338.
 Interstate 295 in New Jersey between mile markers 73 and 76.
 Interstate 476 in Pennsylvania between mile markers 10 and 19.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

These storms have a history of producing widespread wind damage 
across region. SEEK SHELTER NOW inside a sturdy structure and stay 
away from windows!

&&

LAT...LON 4014 7588 4016 7590 4043 7541 4057 7528
      4056 7481 4034 7471 3998 7527 4003 7594
      4011 7594
TIME...MOT...LOC 2127Z 269DEG 28KT 4058 7511 4035 7520 4007 7577 

HAIL...0.75IN
WIND...70MPH
 
$$

Meola
2 follow-up statements
073 
WWUS51 KPHI 262156
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
556 PM EDT Wed May 26 2021

PAC011-262205-
/O.CAN.KPHI.SV.W.0032.000000T0000Z-210526T2230Z/
Berks PA-
556 PM EDT Wed May 26 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN BERKS 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 1000 PM EDT for
central, northern and northwestern New Jersey...and southeastern
Pennsylvania.

LAT...LON 4029 7522 4057 7506 4056 7481 4034 7471
      3998 7527 4002 7582
TIME...MOT...LOC 2155Z 269DEG 28KT 4058 7483 4035 7492 4007 7549 

$$

NJC019-021-PAC017-029-045-091-101-262230-
/O.CON.KPHI.SV.W.0032.000000T0000Z-210526T2230Z/
Hunterdon NJ-Mercer NJ-Montgomery PA-Bucks PA-Chester PA-
Philadelphia PA-Delaware PA-
556 PM EDT Wed May 26 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM EDT
FOR SOUTHEASTERN HUNTERDON...NORTHWESTERN MERCER...SOUTHEASTERN
MONTGOMERY...CENTRAL BUCKS...NORTHEASTERN CHESTER...NORTHWESTERN
PHILADELPHIA AND NORTHEASTERN DELAWARE COUNTIES...

At 555 PM EDT, severe thunderstorms were located along a line
extending from near White House Station to near New Hope to Valley
Forge, moving east at 30 mph.

HAZARD...70 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings.

Locations impacted include...
Philadelphia, Ewing, Norristown, Phoenixville, Lansdale, West
Norriton, East Norriton, Doylestown, Byram, Downingtown,
Conshohocken, Hatboro, Ambler, Collegeville, Flemington, Jenkintown,
Narberth, Chalfont, Tinicum and Pennington.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 311 and 349.
 Northeast Extension between mile markers 21 and 29.
 Interstate 76 in Pennsylvania between mile markers 327 and 338.
 Interstate 295 in New Jersey between mile markers 73 and 76.
 Interstate 476 in Pennsylvania between mile markers 10 and 19.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

These storms are producing widespread wind damage across southeast 
Pennsylvania. SEEK SHELTER NOW inside a sturdy structure and stay 
away from windows.
 
&&

LAT...LON 4029 7522 4057 7506 4056 7481 4034 7471
      3998 7527 4002 7582
TIME...MOT...LOC 2155Z 269DEG 28KT 4058 7483 4035 7492 4007 7549 

HAIL...0.75IN
WIND...70MPH
 
$$

Meola
118 
WWUS51 KPHI 262215
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
615 PM EDT Wed May 26 2021

NJC019-021-PAC017-029-045-091-101-262222-
/O.CAN.KPHI.SV.W.0032.000000T0000Z-210526T2230Z/
Hunterdon NJ-Mercer NJ-Montgomery PA-Bucks PA-Chester PA-
Philadelphia PA-Delaware PA-
615 PM EDT Wed May 26 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN HUNTERDON...
NORTHWESTERN MERCER...SOUTHEASTERN MONTGOMERY...CENTRAL BUCKS...
NORTHEASTERN CHESTER...NORTHWESTERN PHILADELPHIA AND NORTHEASTERN
DELAWARE COUNTIES IS CANCELLED...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 1000 PM EDT for
central, northern and northwestern New Jersey...and southeastern
Pennsylvania.

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

LAT...LON 4029 7522 4057 7506 4056 7481 4034 7471
      3998 7527 4002 7582
TIME...MOT...LOC 2211Z 269DEG 28KT 4058 7466 4035 7475 4007 7532 

$$

Deal

The office that day

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

IssuedProductOfficeCountiesLasted
May 26, 3:39 PM EDTSevere Thunderstorm WarningPHIBerks56 min
May 26, 4:10 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh65 min
May 26, 4:46 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery, Northampton44 min
May 26, 4:52 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery38 min
May 26, 5:34 PM EDTSevere Thunderstorm WarningPHINorthampton41 min
May 26, 5:37 PM EDTSevere Thunderstorm WarningPHIChester53 min
May 26, 5:53 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia67 min
May 26, 6:52 PM EDTSevere Thunderstorm WarningPHIBerks38 min
May 26, 6:08 PM EDTSevere Thunderstorm WarningPHIHunterdon, Middlesex, Morris, Somerset31 min
May 26, 6:49 PM EDTSpecial Marine WarningPHI56 min
May 26, 7:04 PM EDTSpecial Marine WarningPHI26 min
May 26, 7:23 PM EDTSpecial Marine WarningPHI97 min
May 26, 7:56 PM EDTSpecial Marine WarningPHI71 min

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.