Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 108, NWS Philadelphia/Mount Holly

November 2, 2018New Castle County, Delaware; Chester County, Delaware County, Montgomery County, Pennsylvania; Cecil County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Nov 2, 2018, 10:09 PM EDT for New Castle County, Delaware; Chester County, Delaware County, Montgomery County, Pennsylvania; Cecil County, Maryland. It was in force for 51 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: Nov 2, 2018, 10:09 PM EDT (02:09 UTC)
Expired: Nov 2, 2018, 11:00 PM EDT
In force: 51 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Tornado: Possible
Hail: 0.75 in
Wind: 60.0 mph

Counties New Castle County, DE, Cecil County, MD, Chester County, PA, Delaware County, PA, Montgomery County, PA

The radar

The Dover AFB radar (KDOX), 122 km from the middle of the area, began a volume at 02:09 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

Time	Report	Where	Remark
Nov 2, 10:37 PM EDT	TSTM WND DMG	1 Nne West Pottsgrove T, PA	DOWNED TREE IN WIRES NEAR INTERSECTION OF MANATAWNY STREET AND SELL ROAD. TIME ESTIMATED FROM RADAR.
Nov 2, 10:39 PM EDT	TSTM WND DMG	1 Ene Pottstown, PA	SEVERAL LARGE TREES DOWN AT BROOKSIDE COUNTRY CLUB. TIME ESTIMATED FROM RADAR.
Nov 2, 10:39 PM EDT	TSTM WND DMG	1 E Pottstown, PA	PHOTOS SHOWING TWO HARDWOOD TREES DOWN IN A RESIDENTIAL AREA.
Nov 2, 10:39 PM EDT	TSTM WND DMG	Pottstown, PA	LARGE TREE DOWN BLOCKING THE ROADWAY NEAR N WARREN ST AND VIRGINIA AVE.
Nov 2, 10:39 PM EDT	TSTM WND DMG	Pottstown, PA	A ROOF WAS TORN OFF AT THE YORKSHIRE APARTMENTS IN POTTSTOWN.
Nov 2, 10:42 PM EDT	TSTM WND DMG	1 Ese Lower Pottsgrove, PA	DOWNED TREE SEVERELY DAMAGED A HOME ON WOODMERE ROAD.
Nov 2, 10:42 PM EDT	TSTM WND DMG	1 S Lower Pottsgrove Tw, PA	DOWNED TREES ON CARS ON WELSH DRIVE. PORCH ROOF BLEW OFF A HOME ON NORTH PLEASANTVIEW ROAD. TIME ESTIMATED FROM RADAR.
Nov 2, 10:42 PM EDT	TSTM WND DMG	1 S Lower Pottsgrove Tw, PA	DOWNED TREES ON CARS ON WELSH DRIVE. TIME ESTIMATED FROM RADAR.
Nov 2, 10:44 PM EDT	TSTM WND DMG	1 Se Lower Pottsgrove T, PA	DONWED TREE IN WIRES ON SANATOGA ROAD BETWEEN CROWNVIEW ROAD AND SNELL ROAD. ALL LANES CLOSED. TIME ESTIMATED FROM RADAR.
Nov 2, 10:45 PM EDT	HAIL 1	2 W Pottstown, PA
Nov 2, 10:46 PM EDT	TSTM WND GST 54	Pottstown Limerick Airp, PA
Nov 2, 10:59 PM EDT	TSTM WND DMG	Charlestown Twp, PA	WIRES DOWN NEAR VALLEY HILL ROAD AND VALLEY BEECH LANE.
Nov 2, 11:09 PM EDT	TSTM WND DMG	East Whiteland Twp, PA	8 RESIDENCES SUSTAINED DAMAGE FROM DOWNED TREES.
Nov 2, 11:09 PM EDT	TSTM WND DMG	East Whiteland Twp, PA	SEVERAL RESIDENCES, INCLUDING A GROUP HOME, SUSTAINED DAMAGE FROM DOWNED TREES.

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, 2.2 hours before the alert went out and 162 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 34 J/kg
Mixed-layer CIN: -22 J/kg
Mixed-layer LCL: 557 m above ground
0-6 km bulk shear: 70 kt
0-1 km storm-relative helicity: 381 m²/s²
0-3 km storm-relative helicity: 603 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

374 
WUUS51 KPHI 030209
SVRPHI
DEC003-MDC015-PAC029-045-091-030300-
/O.NEW.KPHI.SV.W.0108.181103T0209Z-181103T0300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
1009 PM EDT FRI NOV 2 2018

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northern New Castle County in northern Delaware...
  Cecil County in northeastern Maryland...
  Northwestern Montgomery County in southeastern Pennsylvania...
  Chester County in southeastern Pennsylvania...
  Southwestern Delaware County in southeastern Pennsylvania...

* Until 1100 PM EDT.

* At 1008 PM EDT, severe thunderstorms were located along a line 
  extending from near Wakefield to Perryman, 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...
  Wilmington, Newark, West Chester, Elkton, Calvert, Pottstown,
  Phoenixville, Coatesville, Westtown, Carneys Point, Downingtown,
  Elsmere, Kennett Square, New Castle, Oxford, Royersford,
  Parkesburg, North East, East Greenville and West Grove.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. These storms may cause serious injury and significant
property damage.

&&

LAT...LON 3973 7610 3976 7606 3983 7604 3987 7599
      3995 7600 4004 7593 4011 7594 4025 7569
      4045 7553 4043 7551 3971 7548 3945 7601
      3952 7598 3955 7603 3955 7608 3972 7623
TIME...MOT...LOC 0208Z 220DEG 53KT 3980 7621 3945 7622 

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

SFJ

1 follow-up statement

617 
WWUS51 KPHI 030233
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1033 PM EDT FRI NOV 2 2018

DEC003-MDC015-PAC029-045-091-030300-
/O.CON.KPHI.SV.W.0108.000000T0000Z-181103T0300Z/
New Castle DE-Cecil MD-Montgomery PA-Chester PA-Delaware PA-
1033 PM EDT FRI NOV 2 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1100 PM EDT
FOR NORTHERN NEW CASTLE...CECIL...NORTHWESTERN MONTGOMERY...CHESTER
AND SOUTHWESTERN DELAWARE COUNTIES...

At 1033 PM EDT, severe thunderstorms were located along a line
extending from near Cochranville to near Woodlawn, moving northeast
at 35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Wilmington, Newark, West Chester, Elkton, Calvert, Pottstown,
Phoenixville, Coatesville, Westtown, Carneys Point, Downingtown,
Elsmere, Kennett Square, New Castle, Oxford, Royersford, Parkesburg,
North East, East Greenville and West Grove.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Intense thunderstorm lines can produce brief tornadoes and widespread
significant wind damage. Although a tornado is not immediately
likely, it is best to move to an interior room on the lowest floor of
a building. These storms may cause serious injury and significant
property damage.

&&

LAT...LON 3973 7610 3976 7606 3983 7604 3987 7599
      3995 7600 4004 7593 4011 7594 4025 7569
      4045 7553 4043 7551 3971 7548 3945 7601
      3952 7598 3955 7603 3955 7608 3972 7623
TIME...MOT...LOC 0233Z 233DEG 30KT 3993 7593 3959 7606 

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

SFJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Nov 2, 10:53 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	67 min
Nov 2, 11:25 PM EDT	Areal Flood Advisory	PHI	New Castle	4 hr
Nov 2, 11:43 PM EDT	Special Weather Statement	PHI	Kent	32 min
Nov 3, 12:50 AM EDT	Special Weather Statement	PHI	Sussex	25 min
Nov 2, 8:22 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh, Northampton	4 hr
Nov 2, 9:28 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Chester, Lehigh, Montgomery, Northampton	4 hr
Nov 2, 9:48 PM EDT	Special Weather Statement	PHI	Berks, Chester	27 min
Nov 2, 10:32 PM EDT	Tornado Warning	PHI	Berks, Chester, Montgomery	28 min
Nov 2, 10:36 PM EDT	Special Weather Statement	PHI	Northampton	24 min
Nov 2, 10:45 PM EDT	Areal Flood Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery, Northampton	13 hr
Nov 2, 10:47 PM EDT	Tornado Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery, Northampton	43 min
Nov 2, 10:53 PM EDT	Flash Flood Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery, Northampton	4 hr
Nov 2, 11:23 PM EDT	Tornado Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	24 min
Nov 2, 11:49 PM EDT	Tornado Warning	PHI	Bucks	26 min
Nov 2, 11:53 PM EDT	Areal Flood Advisory	PHI	Bucks	4 hr
Nov 2, 11:53 PM EDT	Special Weather Statement	PHI	Delaware, Philadelphia	37 min
Nov 3, 12:20 AM EDT	Areal Flood Advisory	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	4 hr
Nov 3, 1:03 AM EDT	River Flood Warning	PHI	Lehigh	5 hr
Nov 3, 1:29 AM EDT	Areal Flood Advisory	PHI	Monroe, Northampton	4 hr
Nov 3, 1:41 AM EDT	Areal Flood Advisory	PHI	Bucks	4 hr
Nov 3, 2:03 AM EDT	River Flood Warning	PHI	Chester	6 hr
Nov 3, 2:34 AM EDT	Areal Flood Warning	PHI	Bucks, Northampton	15 hr
Nov 3, 2:40 AM EDT	River Flood Warning	PHI	Montgomery	10 hr
Nov 3, 2:40 AM EDT	River Flood Warning	PHI	Chester, Montgomery, Philadelphia	15 hr
Nov 3, 3:21 AM EDT	Areal Flood Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	4 hr
Nov 3, 5:00 AM EDT	River Flood Warning	PHI	Chester, Delaware	6 hr
Nov 3, 7:01 AM EDT	Areal Flood Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	5 hr
Nov 3, 11:44 AM EDT	Areal Flood Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery, Northampton	8 hr
Nov 3, 5:19 PM EDT	Areal Flood Warning	PHI	Northampton	22 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2018 Severe Thunderstorm Warnings in Delaware, 2018 Severe Thunderstorm Warnings in Maryland, 2018 Every 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.