Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 284, NWS Philadelphia/Mount Holly

August 29, 20204 counties in Pennsylvania; Warren County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 29, 2020, 6:26 PM EDT for 4 counties in Pennsylvania; Warren County, New Jersey. It was in force for 64 min. 8 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: Aug 29, 2020, 6:26 PM EDT (22:26 UTC)
Expired: Aug 29, 2020, 7:30 PM EDT
In force: 64 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Warren County, NJ, Carbon County, PA, Lehigh County, PA, Monroe County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 116 km from the middle of the area, began a volume at 22:27 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
Aug 29, 6:35 PM EDT	TSTM WND DMG	East Penn Twp, PA	TREE DOWN ON WIRES ALONG BERGER CREEK ROAD.
Aug 29, 6:40 PM EDT	TSTM WND DMG	2 W East Penn Twp, PA	DOWNED TREES AND WIRES NEAR PICNIC WOODS ROAD. TIME ESTIMATED FROM RADAR.
Aug 29, 6:49 PM EDT	TSTM WND DMG	1 Sse Jackson Twp, PA	DOWNED TREES AND WIRES NEAR DOE LANE AND BUCK LANE. TIME ESTIMATED FROM RADAR.
Aug 29, 7:10 PM EDT	TSTM WND DMG	Betlehem, PA	TREES DOWN.
Aug 29, 7:13 PM EDT	HAIL 0.25	Allentown, PA
Aug 29, 7:15 PM EDT	TSTM WND DMG	Wilson, PA	TREES DOWN.
Aug 29, 7:17 PM EDT	TSTM WND DMG	1 Wnw Salisbury Twp, PA	DOWNED POWER LINES NEAR BRADFORD STREET. TIME ESTIMATED FROM RADAR.
Aug 29, 7:20 PM EDT	TSTM WND DMG	Alburtis, PA	DOWNED TREES AND WIRES NEAR RIDGEVIEW DRIVE. TIME ESTIMATED FROM RADAR.

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 10.4 hours before the alert went out and 210 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: 348 J/kg
Mixed-layer CIN: -47 J/kg
Mixed-layer LCL: 705 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 119 m²/s²
0-3 km storm-relative helicity: 132 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.0

Open this sounding in Storm Lab

The text

As transmitted.

560 
WUUS51 KPHI 292226
SVRPHI
NJC041-PAC025-077-089-095-292330-
/O.NEW.KPHI.SV.W.0284.200829T2226Z-200829T2330Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
626 PM EDT Sat Aug 29 2020

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southwestern Warren County in northwestern New Jersey...
  Lehigh County in eastern Pennsylvania...
  Carbon County in northeastern Pennsylvania...
  Southwestern Monroe County in northeastern Pennsylvania...
  Northampton County in eastern Pennsylvania...

* Until 730 PM EDT.

* At 625 PM EDT, severe thunderstorms were located along a line
  extending from Meckesville to Tamaqua, moving east at 35 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Minor damage to vehicles is possible. Wind damage to 
           roofs, siding, trees, and power lines is possible.

* Locations impacted include...
  Allentown, Easton, Lehighton, Bethlehem, Forks, Emmaus,
  Northampton, Wilson, Washington, Hellertown, Nazareth, Palmerton,
  Bangor, Jim Thorpe, Slatington, Pen Argyl, Nesquehoning, Wind Gap,
  Bath and Belvidere.

This includes the following highways...
 Northeast Extension between mile markers 46 and 90.
 Interstate 78 in Pennsylvania between mile markers 45 and 76.
 Interstate 78 in New Jersey between mile markers 0 and 7.
 Interstate 80 in Pennsylvania near mile marker 289.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

&&

LAT...LON 4080 7486 4069 7500 4063 7515 4059 7518
      4061 7520 4056 7530 4042 7549 4068 7589
      4074 7576 4086 7593 4108 7555
TIME...MOT...LOC 2225Z 292DEG 32KT 4102 7555 4078 7595 

HAIL...1.00IN
WIND...60MPH
 
$$

Iovino

1 follow-up statement

945 
WWUS51 KPHI 292307
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
707 PM EDT Sat Aug 29 2020

PAC025-089-292316-
/O.CAN.KPHI.SV.W.0284.000000T0000Z-200829T2330Z/
Carbon PA-Monroe PA-
707 PM EDT Sat Aug 29 2020

...THE SEVERE THUNDERSTORM WARNING FOR CARBON AND SOUTHWESTERN 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 4068 7589 4078 7567 4083 7538 4086 7529
      4094 7520 4080 7486 4078 7490 4069 7500
      4063 7515 4059 7518 4061 7520 4056 7530
      4042 7549
TIME...MOT...LOC 2306Z 292DEG 32KT 4088 7511 4064 7551 

$$

NJC041-PAC077-095-292330-
/O.CON.KPHI.SV.W.0284.000000T0000Z-200829T2330Z/
Warren NJ-Lehigh PA-Northampton PA-
707 PM EDT Sat Aug 29 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM EDT
FOR SOUTHWESTERN WARREN...LEHIGH AND NORTHAMPTON COUNTIES...

At 706 PM EDT, severe thunderstorms were located along a line
extending from near Columbia to near Northampton, moving east at 35
mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible. Wind damage to roofs, 
         siding, trees, and power lines is possible.

Locations impacted include...
Allentown, Easton, Bethlehem, Forks, Emmaus, Northampton, Wilson,
Washington, Hellertown, Nazareth, Bangor, Slatington, Pen Argyl, Wind
Gap, Bath, Belvidere, Harmony, Oxford, Alpha and Walnutport.

This includes the following highways...
 Northeast Extension between mile markers 46 and 71.
 Interstate 78 in Pennsylvania between mile markers 45 and 76.
 Interstate 78 in New Jersey between mile markers 0 and 7.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

&&

LAT...LON 4068 7589 4078 7567 4083 7538 4086 7529
      4094 7520 4080 7486 4078 7490 4069 7500
      4063 7515 4059 7518 4061 7520 4056 7530
      4042 7549
TIME...MOT...LOC 2306Z 292DEG 32KT 4088 7511 4064 7551 

HAIL...1.00IN
WIND...60MPH
 
$$

Iovino

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 29, 5:34 PM EDT	Special Weather Statement	PHI	Carbon, Monroe	56 min
Aug 29, 6:08 PM EDT	Special Weather Statement	PHI	Berks, Carbon, Lehigh, Northampton	67 min
Aug 29, 6:50 PM EDT	Special Weather Statement	PHI	Berks	55 min
Aug 29, 7:16 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Lehigh, Montgomery, Northampton	59 min
Aug 29, 9:59 AM EDT	Areal Flood Advisory	PHI	Camden, Gloucester, Salem	4 hr
Aug 29, 11:58 AM EDT	Flash Flood Warning	PHI	Camden, Gloucester, Salem	4 hr
Aug 29, 12:15 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden	4 hr
Aug 29, 12:36 PM EDT	Areal Flood Advisory	PHI	Monmouth, Ocean	4 hr
Aug 29, 2:27 PM EDT	Areal Flood Advisory	PHI	Ocean	3 hr
Aug 29, 2:46 PM EDT	Areal Flood Advisory	PHI	Atlantic, Cape May, Cumberland	3 hr
Aug 29, 3:04 PM EDT	Small Craft Advisory	PHI		15 hr
Aug 29, 3:53 PM EDT	Areal Flood Warning	PHI	Gloucester, Salem	4 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2020 Severe Thunderstorm Warnings in New Jersey, 2020 Every 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.