Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 21, NWS Philadelphia/Mount Holly

April 26, 2019Delaware County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 26, 2019, 4:53 PM EDT for Delaware County, Pennsylvania. It was in force for 52 min. 1 report 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 26, 2019, 4:53 PM EDT (20:53 UTC)
Expired: Apr 26, 2019, 5:45 PM EDT
In force: 52 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County Delaware County, PA

The radar

The Philadelphia radar (KDIX), 84 km from the middle of the area, began a volume at 20:55 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
Apr 26, 5:14 PM EDT	TSTM WND DMG	1 Nnw Lima, PA	DOWNED TREE ON WIRES NEAR THE INTERSECTION OF MIDDLETOWN ROAD AND FORGE ROAD IN MIDDLETOWN TWP. 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.

Issued	Product	Office	Lasted
Apr 26, 1:33 PM EDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.9 hours before the alert went out and 204 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: 49 J/kg
Mixed-layer CIN: -221 J/kg
Mixed-layer LCL: 715 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 293 m²/s²
0-3 km storm-relative helicity: 355 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

As transmitted.

879 
WUUS51 KPHI 262053
SVRPHI
PAC045-262145-
/O.NEW.KPHI.SV.W.0021.190426T2053Z-190426T2145Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
453 PM EDT FRI APR 26 2019

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Delaware County in southeastern Pennsylvania...

* Until 545 PM EDT.

* At 452 PM EDT, a severe thunderstorm was located near Ashland, or 7
  miles south of West Chester, moving northeast at 40 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Chester, Yeadon, Folcroft, Swarthmore, Paulsboro, East Lansdowne,
  Darby Township, Cheyney, Elam, Trout Lake, Chelsea, Radnor
  Township, Gradyville, Broomall, Newtown Square, Chester Township,
  Drexel Hill, Lima, Nether Providence Township and Philadelphia
  International Arpt.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

A tornado watch remains in effect until 900 PM EDT for northern
Delaware...southern New Jersey...and southeastern Pennsylvania.

LAT...LON 3993 7554 3998 7544 4000 7545 4003 7540
      4004 7541 4006 7536 3997 7528 3996 7525
      3994 7524 3988 7526 3987 7521 3985 7525
      3985 7533 3980 7541 3984 7550 3984 7559
      3986 7560
TIME...MOT...LOC 2052Z 247DEG 36KT 3985 7562 

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

jjm

1 follow-up statement

580 
WWUS51 KPHI 262112
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
512 PM EDT FRI APR 26 2019

PAC045-262145-
/O.CON.KPHI.SV.W.0021.000000T0000Z-190426T2145Z/
Delaware PA-
512 PM EDT FRI APR 26 2019

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 545 PM EDT
FOR DELAWARE COUNTY...

At 511 PM EDT, a severe thunderstorm was located over Lima, or 9
miles east of West Chester, moving east 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...
Chester, Yeadon, Folcroft, Swarthmore, Paulsboro, East Lansdowne,
Darby Township, Cheyney, Trout Lake, Chelsea, Radnor Township,
Gradyville, Broomall, Newtown Square, Chester Township, Drexel Hill, 
Lima, and Nether Providence Township.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

A tornado watch remains in effect until 900 PM EDT for northern
Delaware...southern New Jersey...and southeastern Pennsylvania.

LAT...LON 3983 7548 3994 7553 3998 7544 4000 7545
      4003 7540 4004 7541 4006 7536 3997 7528
      3996 7525 3994 7524 3988 7526 3987 7521
      3985 7525 3985 7533 3980 7541
TIME...MOT...LOC 2111Z 255DEG 44KT 3992 7543 

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

jjm

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 26, 11:45 AM EDT	Special Weather Statement	PHI	Philadelphia	45 min
Apr 26, 3:51 PM EDT	Special Weather Statement	PHI	Berks, Chester	69 min
Apr 26, 4:19 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester	56 min
Apr 26, 4:28 PM EDT	Severe Thunderstorm Warning	PHI	Chester	47 min
Apr 26, 4:59 PM EDT	Areal Flood Advisory	PHI	Berks, Chester, Delaware, Montgomery	4 hr
Apr 26, 5:07 PM EDT	Special Weather Statement	PHI	Bucks, Montgomery, Philadelphia	53 min
Apr 26, 5:15 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	4 hr
Apr 26, 5:17 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery	43 min
Apr 26, 5:28 PM EDT	Severe Thunderstorm Warning	PHI	Montgomery, Philadelphia	47 min
Apr 26, 5:44 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	61 min
Apr 26, 5:57 PM EDT	Areal Flood Advisory	PHI	Bucks	4 hr
Apr 26, 6:34 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Carbon, Lehigh, Monroe, Montgomery and 1 more	2 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2019 Every 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.