Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 16, NWS Philadelphia/Mount Holly

April 9, 20205 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 9, 2020, 12:23 PM EDT for 5 counties in Pennsylvania. It was in force for 52 min. 14 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
Apr 9, 2020, 12:23 PM EDT (16:23 UTC)
Expired
Apr 9, 2020, 1:15 PM EDT
In force
52 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Berks County, PA, Bucks County, PA, Chester County, PA, Lehigh County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 121 km from the middle of the area, began a volume at 16:23 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
Apr 9, 12:24 PM EDTTSTM WND DMGReading, PAPHOTOS OF SEVERAL LARGE TREES DOWN IN THE AREA. TIME ESTIMATED FROM RADAR.
Apr 9, 12:29 PM EDTHAIL 0.25Exeter Twp, PA
Apr 9, 12:36 PM EDTHAIL 0.25Wyomissing, PA
Apr 9, 12:40 PM EDTHAIL 0.25Gilbertsville, PAPEA SIZE HAIL REPORTED IN GILBERTSVILLE.
Apr 9, 12:42 PM EDTTSTM WND DMGBoyertown, PAUTILITY POLE SNAPPED IN HALF IN BOYERTOWN. TIME ESTIMATED FROM RADAR.
Apr 9, 12:42 PM EDTHAIL 0.252 Wsw Red Hill, PA
Apr 9, 12:47 PM EDTHAIL 0.251 Ne East Vincent Twp, PABRIEF PERIOD OF PEA SIZED HAIL.
Apr 9, 12:48 PM EDTTSTM WND DMGPerkiomenville, PATREES AND WIRES DOWN. PEA SIZE HAIL ALSO REPORTED.
Apr 9, 12:50 PM EDTTSTM WND DMG2 W Phoenixville, PATREE DOWN NEAR TOWNSHIP LINE ROAD AND NUTT ROAD.
Apr 9, 12:50 PM EDTHAIL 0.25Trumbauersville, PA
Apr 9, 12:50 PM EDTHAIL 0.7Boyertown, PA
Apr 9, 12:54 PM EDTTSTM WND DMG1 Nw Sellersville, PASEVERAL REPORTS OF DOWNED TREES AND WIRES IN THE AREA. TIME ESTIMATED FROM RADAR.
Apr 9, 1:00 PM EDTTSTM WND DMG1 E Oaks, PATREE DOWN ON A HOUSE IN LOWER PROVIDENCE TOWNSHIP.
Apr 9, 1:05 PM EDTTSTM WND DMG1 N Reading, PAVIDEO POSTED TO SOCIAL MEDIA SHOWS NUMEROUS TREES UPROOTED AND DOWNED, AS WELL AS NUMEROUS DOWNED POWER LINES. TIME ESTIMATED.

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
Apr 9, 12:01 PM EDTSevere Thunderstorm WatchSPC4 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 4.4 hours before the alert went out and 192 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 2020-04-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 20 joules per kilogram.LCLLFCEL10008507005003002001001 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, Washington/Dulle, VA at 12:00Z on 2020-04-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 394 square meters per square second.1939587897117Sfc1 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
20 J/kg
Mixed-layer CIN
-589 J/kg
Mixed-layer LCL
1002 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
394 m²/s²
0-3 km storm-relative helicity
416 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

750 
WUUS51 KPHI 091623
SVRPHI
PAC011-017-029-077-091-091715-
/O.NEW.KPHI.SV.W.0016.200409T1623Z-200409T1715Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
1223 PM EDT Thu Apr 9 2020

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southeastern Berks County in eastern Pennsylvania...
  South central Lehigh County in eastern Pennsylvania...
  Montgomery County in southeastern Pennsylvania...
  Northwestern Bucks County in southeastern Pennsylvania...
  Chester County in southeastern Pennsylvania...

* Until 115 PM EDT.

* At 1222 PM EDT, severe thunderstorms were located along a line
  extending from Laureldale to near Adamstown to near Strasburg,
  moving east at 55 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...
  Reading, West Chester, Norristown, Pottstown, Phoenixville,
  Lansdale, West Norriton, East Norriton, Coatesville, Wyomissing,
  Quakertown, Perkasie, Downingtown, Souderton, Bedminster,
  Birdsboro, Collegeville, Royersford, Fleetwood and Chalfont.

This includes the following highways...
 Pennsylvania Turnpike between exits 298 and 326.
 Northeast Extension between exits A31 and A44.
 Interstate 176 in Pennsylvania between mile markers 1 and 11.
 Interstate 76 in Pennsylvania near mile marker 327.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4044 7597 4050 7510 4021 7526 3991 7558
      3994 7598 3994 7599 3995 7600 4004 7593
      4011 7594 4014 7588 4026 7607
TIME...MOT...LOC 1622Z 266DEG 49KT 4039 7592 4023 7601 4003 7621 

HAIL...0.75IN
WIND...60MPH
 
$$

MPS
2 follow-up statements
223 
WWUS51 KPHI 091652
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1252 PM EDT Thu Apr 9 2020

PAC011-077-091701-
/O.CAN.KPHI.SV.W.0016.000000T0000Z-200409T1715Z/
Berks PA-Lehigh PA-
1252 PM EDT Thu Apr 9 2020

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN BERKS AND SOUTH
CENTRAL LEHIGH COUNTIES 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 400 PM EDT for
southeastern Pennsylvania.

LAT...LON 4020 7565 4048 7542 4050 7510 4020 7526
      3993 7556 3994 7595
TIME...MOT...LOC 1651Z 265DEG 46KT 4046 7534 4020 7552 3999 7577 

$$

PAC017-029-091-091715-
/O.CON.KPHI.SV.W.0016.000000T0000Z-200409T1715Z/
Montgomery PA-Bucks PA-Chester PA-
1252 PM EDT Thu Apr 9 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 115 PM EDT
FOR CENTRAL MONTGOMERY...NORTHWESTERN BUCKS AND CENTRAL CHESTER
COUNTIES...

At 1251 PM EDT, severe thunderstorms were located along a line
extending from Quakertown to Royersford to near Coatesville, moving
east at 50 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...
West Chester, Norristown, Pottstown, Phoenixville, Lansdale, West
Norriton, East Norriton, Coatesville, Quakertown, Perkasie,
Downingtown, Souderton, Bedminster, Collegeville, Royersford,
Chalfont, Parkesburg, Trappe, Hatfield and Dublin.

This includes the following highways...
 Pennsylvania Turnpike between exits 312 and 326.
 Northeast Extension between exits A31 and A44.
 Interstate 76 in Pennsylvania near mile marker 327.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4020 7565 4048 7542 4050 7510 4020 7526
      3993 7556 3994 7595
TIME...MOT...LOC 1651Z 265DEG 46KT 4046 7534 4020 7552 3999 7577 

HAIL...0.75IN
WIND...60MPH
 
$$

MPS
587 
WWUS51 KPHI 091705
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
105 PM EDT Thu Apr 9 2020

PAC017-029-091-091715-
/O.EXP.KPHI.SV.W.0016.000000T0000Z-200409T1715Z/
Montgomery PA-Bucks PA-Chester PA-
105 PM EDT Thu Apr 9 2020

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL MONTGOMERY...
NORTHWESTERN BUCKS AND CENTRAL CHESTER COUNTIES WILL EXPIRE AT 115 PM
EDT...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning will be allowed to expire.  However, gusty 
winds are still possible with these thunderstorms.

A Severe Thunderstorm Watch remains in effect until 400 PM EDT for
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 4020 7565 4048 7542 4050 7510 4020 7526
      3993 7556 3994 7595
TIME...MOT...LOC 1705Z 266DEG 49KT 4047 7513 4021 7531 4000 7556 

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 9, 12:05 PM EDTSpecial Weather StatementPHIBerks, Carbon, Lehigh, Monroe, Northampton40 min
Apr 9, 1:00 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia45 min
Apr 9, 1:12 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Philadelphia48 min
Apr 9, 1:23 PM EDTSevere Thunderstorm WarningPHIBucks52 min
Apr 9, 1:26 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Chester, Delaware, Montgomery, Philadelphia49 min
Apr 9, 1:33 PM EDTSevere Thunderstorm WarningPHIBucks, Delaware, Philadelphia42 min
Apr 9, 3:32 PM EDTWind AdvisoryPHIBerks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more27 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2020Every severe thunderstorm warning in 2020

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.