Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 402, NWS Philadelphia/Mount Holly

October 31, 2019Bucks County, Chester County, Montgomery County, Pennsylvania; Cecil County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Oct 31, 2019, 10:23 PM EDT for Bucks County, Chester County, Montgomery County, Pennsylvania; Cecil County, Maryland. It was in force for 67 min. 11 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
Oct 31, 2019, 10:23 PM EDT (02:23 UTC)
Expired
Oct 31, 2019, 11:30 PM EDT
In force
67 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Cecil County, MD, Bucks County, PA, Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 101 km from the middle of the area, began a volume at 02:25 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
Oct 31, 10:23 PM EDTTSTM WND DMG2 Sw East Brandywine Tw, PALARGE TREE DOWN NEAR THE INTERSECTION OF REECEVILLE ROAD AND CALN MEETINGHOUSE ROAD. TIME ESTIMATED FROM RADAR.
Oct 31, 11:09 PM EDTTSTM WND DMG1 Ne Uwchlan Twp, PAREPORT FROM MPING: 1-INCH TREE LIMBS BROKEN; SHINGLES BLOWN OFF. TIME ESTIMATED FROM RADAR.
Oct 31, 11:16 PM EDTTSTM WND DMG2 Ne Kennett Square, PADOWNED TREE ON U.S. HIGHWAY 1 NEAR SCHOOL HOUSE ROAD. TIME ESTIMATED FROM RADAR.
Oct 31, 11:21 PM EDTTSTM WND DMG2 S Westtown, PADOWNED TREE ON DILWORTHTOWN ROAD NEAR BINTON LAKE ROAD. TIME ESTIMATED FROM RADAR.
Oct 31, 11:24 PM EDTTSTM WND DMG1 Ene Westtown, PADOWNED TREE NEAR THE INTERSECTION OF ROUTE 926 AND WESTTOWN ROAD. TIME ESTIMATED FROM RADAR.
Oct 31, 11:24 PM EDTTSTM WND DMG1 Nnw West Goshen, PADOWNED TREE ON FERN HILL ROAD. TIME ESTIMATED FROM RADAR.
Oct 31, 11:25 PM EDTTORNADOGlen Mills, PA*** 2 INJ *** A TORNADO EMBEDDED IN A LARGER AREA OF STRAIGHT LINE WINDS TOUCHED DOWN JUST SOUTHWEST OF THE COBBLESTONE AT THORNBURY SUBDIVISION IN THE TOWN OF GLEN MILLS, DELAWARE COUNTY AT 11:25 PM EDT, THURSDAY, OCTOBER 31, 2019. DAMAGE NEAR THE BEGINNING O
Oct 31, 11:29 PM EDTTSTM WND DMGKintnersville, PADOWNED TREE ON STATE HIGHWAY 611 NEAR KINTNER ROAD. TIME ESTIMATED FROM RADAR.
Oct 31, 11:32 PM EDTTSTM WND DMG1 Se Berwyn, PADOWNED TREE AND WIRES NEAR THE INTERSECTION OF SUGARTOWN ROAD AND FAIRFIELD ROAD. TIME ESTIMATED FROM RADAR.
Oct 31, 11:34 PM EDTTSTM WND DMG1 Nw Wayne, PAMULTIPLE TREES SNAPPED WITH LARGE LIMBS DOWN AT ST. DAVIDS GOLF CLUB IN WAYNE. TIME ESTIMATED FROM RADAR.
Oct 31, 11:37 PM EDTTSTM WND DMG1 Wsw West Conshohocken, PADOWNED TREE NEAR THE INTERSTATE 76 AND 476 INTERCHANGE. 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
Oct 31, 7:56 PM EDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 2.4 hours before the alert went out and 201 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 2019-11-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 529 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 2019-11-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 623 square meters per square second.1939587897Sfc1 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
529 J/kg
Mixed-layer CIN
-20 J/kg
Mixed-layer LCL
827 m above ground
0-6 km bulk shear
72 kt
0-1 km storm-relative helicity
623 m²/s²
0-3 km storm-relative helicity
752 m²/s²
Significant tornado parameter
2.5
Supercell composite
9.8

Open this sounding in Storm Lab

The text

As transmitted.

188 
WUUS51 KPHI 010223
SVRPHI
MDC015-PAC017-029-091-010330-
/O.NEW.KPHI.SV.W.0402.191101T0223Z-191101T0330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
1023 PM EDT Thu Oct 31 2019

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Cecil County in northeastern Maryland...
  Montgomery County in southeastern Pennsylvania...
  Northwestern Bucks County in southeastern Pennsylvania...
  Chester County in southeastern Pennsylvania...

* Until 1130 PM EDT.

* At 1023 PM EDT, severe thunderstorms were located along a line
  extending from East Greenville to near Aberdeen, moving northeast
  at 65 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  West Chester, Elkton, Calvert, Norristown, Pottstown, Phoenixville,
  Lansdale, West Norriton, East Norriton, Coatesville, Westtown,
  Quakertown, Perkasie, Doylestown, Downingtown, Conshohocken,
  Souderton, Bedminster, Ambler and Kennett Square.

This includes the following highways...
 Interstate 95 in Maryland between mile markers 91 and 109.
 Interstate 95 in Delaware near mile marker 0.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3976 7606 3987 7599 4011 7594 4023 7571
      4037 7559 4058 7527 4061 7520 4057 7518
      4057 7511 4042 7506 4041 7499 4003 7532
      4006 7535 4006 7536 3984 7559 3972 7579
      3952 7578 3955 7608 3972 7623
TIME...MOT...LOC 0223Z 237DEG 55KT 4039 7553 3958 7622 

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

Iovino
1 follow-up statement
306 
WWUS51 KPHI 010301
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1101 PM EDT Thu Oct 31 2019

MDC015-PAC017-029-091-010330-
/O.CON.KPHI.SV.W.0402.000000T0000Z-191101T0330Z/
Cecil MD-Montgomery PA-Bucks PA-Chester PA-
1101 PM EDT Thu Oct 31 2019

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1130 PM EDT
FOR CECIL...MONTGOMERY...NORTHWESTERN BUCKS AND CHESTER COUNTIES...

At 1101 PM EDT, severe thunderstorms were located along a line
extending from near Quakertown to West Nottingham, moving northeast
at 50 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
West Chester, Elkton, Calvert, Norristown, Pottstown, Phoenixville,
Lansdale, West Norriton, East Norriton, Coatesville, Westtown,
Quakertown, Perkasie, Doylestown, Downingtown, Conshohocken,
Souderton, Bedminster, Ambler and Kennett Square.

This includes the following highways...
 Interstate 95 in Maryland between mile markers 91 and 109.
 Interstate 95 in Delaware near mile marker 0.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3976 7606 3987 7599 4011 7594 4023 7571
      4037 7559 4058 7527 4061 7520 4057 7518
      4057 7511 4042 7506 4041 7499 4003 7532
      4006 7535 4006 7536 3984 7559 3972 7579
      3952 7578 3955 7608 3972 7623
TIME...MOT...LOC 0301Z 214DEG 44KT 4047 7538 3966 7607 

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

Iovino

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 31, 8:11 PM EDTSevere Thunderstorm WarningPHIBerks, Carbon, Lehigh64 min
Oct 31, 8:58 PM EDTSevere Thunderstorm WarningPHIBerks, Carbon, Lehigh, Monroe, Northampton62 min
Oct 31, 9:35 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Montgomery55 min
Oct 31, 9:41 PM EDTFlash Flood WarningPHIBerks4 hr
Oct 31, 9:56 PM EDTAreal Flood AdvisoryPHICarbon, Monroe4 hr
Oct 31, 9:56 PM EDTSevere Thunderstorm WarningPHICarbon, Lehigh, Monroe, Northampton64 min
Oct 31, 10:43 PM EDTSevere Thunderstorm WarningPHIMonroe, Northampton77 min
Oct 31, 10:45 PM EDTAreal Flood AdvisoryPHIBerks, Bucks, Chester, Lehigh, Montgomery, Northampton4 hr
Oct 31, 11:08 PM EDTFlash Flood WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery, Northampton4 hr
Oct 31, 11:14 PM EDTFlash Flood WarningPHICarbon, Monroe, Northampton4 hr
Oct 31, 11:15 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia60 min
Oct 31, 11:32 PM EDTTornado WarningPHIChester, Delaware, Montgomery, Philadelphia14 min
Oct 31, 11:54 PM EDTSevere Thunderstorm WarningPHIBucks66 min
Oct 31, 11:54 PM EDTTornado WarningPHIBucks36 min
Nov 1, 1:43 AM EDTAreal Flood WarningPHIBerks4 hr
Nov 1, 2:28 AM EDTRiver Flood WarningPHIChester4 hr
Nov 1, 3:02 AM EDTAreal Flood WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery, Northampton5 hr
Nov 1, 3:06 AM EDTAreal Flood WarningPHICarbon, Monroe, Northampton4 hr
Nov 1, 3:31 AM EDTFreeze WatchPHIBerks, Bucks, Chester, Lehigh, Montgomery, Northampton6 hr
Nov 1, 9:12 AM EDTFreeze WarningPHIBerks, Bucks, Chester, Delaware, Lehigh, Montgomery and 1 more25 hr
Nov 1, 3:16 PM EDTFrost AdvisoryPHIPhiladelphia19 hr
Oct 31, 10:47 PM EDTSevere Thunderstorm WarningPHICaroline, Cecil, Kent, Queen Anne's, Talbot73 min
Oct 31, 11:10 PM EDTTornado WarningPHICaroline, Kent, Queen Anne's, Talbot35 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2019Severe Thunderstorm Warnings in Maryland, 2019Every severe thunderstorm warning in 2019

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.