Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 11, NWS Philadelphia/Mount Holly

March 3, 20209 counties in Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Mar 3, 2020, 8:39 PM EST for 9 counties in Pennsylvania; New Castle County, Delaware. It was in force for 51 min. 10 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
Mar 3, 2020, 8:39 PM EST (01:39 UTC)
Expired
Mar 3, 2020, 9:30 PM EST
In force
51 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties New Castle County, DE, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 103 km from the middle of the area, began a volume at 01:42 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
Mar 3, 8:45 PM ESTTSTM WND DMGWest Nantmeal Twp., PACORRECTS PREVIOUS TSTM WND DMG REPORT FROM WEST NANTMEAL TWP.. TREE DOWN. TIME CORRECTED FROM RADAR.
Mar 3, 8:50 PM ESTTSTM WND DMGGlenmoore, PACORRECTS PREVIOUS TSTM WND DMG REPORT FROM GLENMOORE. AT LEAST TWO EMERGENCY CALLS FOR DOWNED TREES IN THE AREA. TIME CORRECTED FROM RADAR.
Mar 3, 8:55 PM ESTTSTM WND GST 60Center Valley, PAESTIMATED GUST UP TO 60 MPH. TIME ESTIMATED FROM RADAR.
Mar 3, 8:55 PM ESTHAIL 0.25Center Valley, PAPEA SIZE HAIL. TIME ESTIMATED FROM RADAR.
Mar 3, 9:00 PM ESTTSTM WND DMGDownington, PALARGE TREE DOWN. TIME ESTIMATED FROM RADAR.
Mar 3, 9:05 PM ESTTSTM WND DMGDistrict Twp, PA*** 1 INJ *** TWO SEPARATE INCIDENTS OF TREES DOWN ON CARS ON HUFFS CHURCH RD. ONE INJURY REPORTED OF UNKNOWN SEVERITY. TIME ESTIMATED FROM RADAR.
Mar 3, 9:05 PM ESTTSTM WND GST 53West Grove, PADEOS STATION.
Mar 3, 9:08 PM ESTTSTM WND DMG1 Nnw Hanover Twp, PAPOWER LINES DOWN. TIME ESTIMATED FROM RADAR.
Mar 3, 9:22 PM ESTTSTM WND GST 60Thornbury Twp, PAESTIMATED WIND GUST OF 60MPH OR HIGHER WITH A LARGE TREE LIMB DOWN.
Mar 3, 9:30 PM ESTTSTM WND GST 621 Sse Fort Washington, PAPA DOT GAUGE.

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

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 1.7 hours before the alert went out and 221 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 00:00Z on 2020-03-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 30 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 00:00Z on 2020-03-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 206 square meters per square second.1939587897117136156Sfc1 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
30 J/kg
Mixed-layer CIN
-105 J/kg
Mixed-layer LCL
1207 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
206 m²/s²
0-3 km storm-relative helicity
275 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

764 
WUUS51 KPHI 040139
SVRPHI
DEC003-PAC011-017-025-029-045-077-089-091-095-040230-
/O.NEW.KPHI.SV.W.0011.200304T0139Z-200304T0230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
839 PM EST Tue Mar 3 2020

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  North central New Castle County in northern Delaware...
  Eastern Berks County in eastern Pennsylvania...
  Lehigh County in eastern Pennsylvania...
  Montgomery County in southeastern Pennsylvania...
  Southeastern Carbon County in northeastern Pennsylvania...
  Bucks County in southeastern Pennsylvania...
  Chester County in southeastern Pennsylvania...
  South central Monroe County in northeastern Pennsylvania...
  Northwestern Delaware County in southeastern Pennsylvania...
  Northampton County in eastern Pennsylvania...

* Until 930 PM EST.

* At 838 PM EST, severe thunderstorms were located along a line
  extending from near Schnecksville to near Elverson to Quarryville,
  moving east at 45 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  Allentown, Easton, West Chester, Bethlehem, Norristown, Pottstown,
  Phoenixville, Lansdale, West Norriton, Forks, East Norriton,
  Coatesville, Emmaus, Westtown, Northampton, Quakertown, Perkasie,
  Doylestown, Byram and Wilson.

This includes the following highways...
 Interstate 78 in Pennsylvania between mile markers 43 and 76.
 Interstate 476 in Pennsylvania between mile markers 10 and 19.
 Pennsylvania Turnpike between exits 298 and 343.
 Northeast Extension between exits A20 and A56.
 Interstate 76 in Pennsylvania between mile markers 327 and 335.

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.

This severe thunderstorm may contain little or no lightning. Do not
wait until you hear thunder before taking cover.

&&

LAT...LON 3987 7599 3995 7600 4004 7593 4011 7594
      4014 7588 4016 7590 4019 7586 4078 7573
      4091 7508 4086 7505 4075 7519 4061 7520
      4057 7518 4058 7512 4054 7507 4045 7507
      4040 7503 4020 7506 3977 7565 3982 7603
TIME...MOT...LOC 0138Z 267DEG 41KT 4066 7566 4020 7577 3991 7614 

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

MPS
2 follow-up statements
555 
WWUS51 KPHI 040212
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
912 PM EST Tue Mar 3 2020

PAC011-025-089-040221-
/O.CAN.KPHI.SV.W.0011.000000T0000Z-200304T0230Z/
Berks PA-Carbon PA-Monroe PA-
912 PM EST Tue Mar 3 2020

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN BERKS...SOUTHEASTERN
CARBON AND SOUTH CENTRAL MONROE COUNTIES IS CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

LAT...LON 3981 7595 4071 7530 4091 7508 4086 7505
      4075 7519 4061 7520 4057 7518 4058 7512
      4054 7507 4045 7507 4040 7503 4020 7506
      3977 7565
TIME...MOT...LOC 0211Z 267DEG 41KT 4068 7516 4022 7528 3993 7565 

$$

DEC003-PAC017-029-045-077-091-095-040230-
/O.CON.KPHI.SV.W.0011.000000T0000Z-200304T0230Z/
New Castle DE-Lehigh PA-Montgomery PA-Bucks PA-Chester PA-
Delaware PA-Northampton PA-
912 PM EST Tue Mar 3 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 PM EST
FOR NORTH CENTRAL NEW CASTLE...SOUTHEASTERN LEHIGH...MONTGOMERY...
BUCKS...CHESTER...NORTHWESTERN DELAWARE AND SOUTHEASTERN NORTHAMPTON
COUNTIES...

At 911 PM EST, severe thunderstorms were located along a line
extending from Alpha to Lansdale to near Marshallton, moving east at
45 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

Locations impacted include...
Easton, West Chester, Bethlehem, Norristown, Pottstown, Phoenixville,
Lansdale, West Norriton, Forks, East Norriton, Coatesville, Westtown,
Quakertown, Perkasie, Doylestown, Byram, Wilson, Downingtown,
Conshohocken and Hatboro.

This includes the following highways...
 Interstate 78 in Pennsylvania between mile markers 64 and 76.
 Interstate 476 in Pennsylvania between mile markers 10 and 19.
 Pennsylvania Turnpike between exits 312 and 343.
 Northeast Extension between exits A20 and A44.
 Interstate 76 in Pennsylvania between mile markers 327 and 335.

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.

This severe thunderstorm may contain little or no lightning. Do not
wait until you hear thunder before taking cover.

&&

LAT...LON 3981 7595 4071 7530 4091 7508 4086 7505
      4075 7519 4061 7520 4057 7518 4058 7512
      4054 7507 4045 7507 4040 7503 4020 7506
      3977 7565
TIME...MOT...LOC 0211Z 267DEG 41KT 4068 7516 4022 7528 3993 7565 

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

MPS
258 
WWUS51 KPHI 040220
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
920 PM EST Tue Mar 3 2020

DEC003-PAC017-029-045-077-091-095-040230-
/O.EXP.KPHI.SV.W.0011.000000T0000Z-200304T0230Z/
New Castle DE-Lehigh PA-Montgomery PA-Bucks PA-Chester PA-
Delaware PA-Northampton PA-
920 PM EST Tue Mar 3 2020

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL NEW CASTLE...
SOUTHEASTERN LEHIGH...MONTGOMERY...BUCKS...CHESTER...NORTHWESTERN
DELAWARE AND SOUTHEASTERN NORTHAMPTON COUNTIES WILL EXPIRE AT 930 PM
EST...
    
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.

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 3981 7595 4071 7530 4091 7508 4086 7505
      4075 7519 4061 7520 4057 7518 4058 7512
      4054 7507 4045 7507 4040 7503 4020 7506
      3977 7565
TIME...MOT...LOC 0220Z 267DEG 41KT 4069 7503 4023 7515 3994 7552 

$$

MPS

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 3, 8:09 PM ESTSpecial Weather StatementPHIBerks, Carbon, Chester, Delaware, Lehigh, Monroe and 2 more51 min
Mar 3, 9:09 PM ESTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia51 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2020Severe Thunderstorm Warnings in Delaware, 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.