Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 300, NWS Philadelphia/Mount Holly

September 13, 2021Hunterdon County, Warren County, New Jersey; 4 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 13, 2021, 8:41 PM EDT for Hunterdon County, Warren County, New Jersey; 4 counties in Pennsylvania. It was in force for 49 min. 3 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: Sep 13, 2021, 8:41 PM EDT (00:41 UTC)
Expired: Sep 13, 2021, 9:30 PM EDT
In force: 49 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

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

The radar

The Philadelphia radar (KDIX), 117 km from the middle of the area, began a volume at 00:41 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
Sep 13, 9:00 PM EDT	TSTM WND DMG	Bangor, PA	WIRES DOWN. TIMES ESTIMATED FROM RADAR.
Sep 13, 9:06 PM EDT	TSTM WND GST 48	Whitehall Twp, PA
Sep 13, 9:10 PM EDT	TSTM WND GST 58	North Catasauqua, PA	58 MPH GUST RECORDED IN NORTH CATASAUQUA.

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
Sep 13, 7:44 PM EDT	Severe Thunderstorm Watch	SPC	4 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 0.7 hours before the alert went out and 209 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: 90 J/kg
Mixed-layer CIN: -236 J/kg
Mixed-layer LCL: 1411 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 82 m²/s²
0-3 km storm-relative helicity: 139 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

304 
WUUS51 KPHI 140041
SVRPHI
NJC019-041-PAC025-077-089-095-140130-
/O.NEW.KPHI.SV.W.0300.210914T0041Z-210914T0130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
841 PM EDT Mon Sep 13 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northwestern Hunterdon County in northwestern New Jersey...
  Central Warren County in northwestern New Jersey...
  Lehigh County in eastern Pennsylvania...
  Southeastern Carbon County in northeastern Pennsylvania...
  South central Monroe County in northeastern Pennsylvania...
  Northampton County in eastern Pennsylvania...

* Until 930 PM EDT.

* At 840 PM EDT, severe thunderstorms were located along a line
  extending from Stormville to Kresgeville to Nesquehoning to
  Tuscarora, moving east at 40 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, Slatington, Pen Argyl, Wind Gap, Bath, Belvidere, Harmony
  and Oxford.

This includes the following highways...
 Northeast Extension between mile markers 47 and 75.
 Interstate 78 in Pennsylvania between mile markers 45 and 76.
 Interstate 78 in New Jersey between mile markers 0 and 9.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to large hail and damaging winds, frequent cloud to
ground lightning is occurring with these storms. Move indoors
immediately. Remember, if you can hear thunder, you are close enough
to be struck by lightning.

&&

LAT...LON 4087 7485 4067 7501 4059 7519 4061 7520
      4044 7552 4068 7589 4074 7576 4078 7583
      4097 7526
TIME...MOT...LOC 0040Z 287DEG 36KT 4094 7526 4088 7548 4086 7580 4075
7605

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Gorse

2 follow-up statements

913 
WWUS51 KPHI 140104
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
904 PM EDT Mon Sep 13 2021

NJC019-041-PAC025-077-089-095-140130-
/O.CON.KPHI.SV.W.0300.000000T0000Z-210914T0130Z/
Hunterdon NJ-Warren NJ-Lehigh PA-Carbon PA-Monroe PA-Northampton PA-
904 PM EDT Mon Sep 13 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 PM EDT
FOR NORTHWESTERN HUNTERDON...CENTRAL WARREN...LEHIGH...SOUTHEASTERN
CARBON...SOUTH CENTRAL MONROE AND NORTHAMPTON COUNTIES...

At 904 PM EDT, severe thunderstorms were located along a line
extending from near Oxford to near Harmony to Beersville to near New
Tripoli, moving east at 50 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,
Slatington, Pen Argyl, Wind Gap, Bath, Belvidere, Harmony and Oxford.

This includes the following highways...
 Northeast Extension between mile markers 47 and 75.
 Interstate 78 in Pennsylvania between mile markers 45 and 76.
 Interstate 78 in New Jersey between mile markers 0 and 9.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Frequent cloud to ground lightning is occurring with these storms.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

&&

LAT...LON 4087 7485 4067 7501 4059 7519 4061 7520
      4044 7552 4068 7589 4074 7576 4078 7583
      4097 7526
TIME...MOT...LOC 0104Z 291DEG 42KT 4083 7493 4077 7515 4075 7547 4065
7572

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Gorse

333 
WWUS51 KPHI 140118
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
918 PM EDT Mon Sep 13 2021

PAC025-089-140128-
/O.CAN.KPHI.SV.W.0300.000000T0000Z-210914T0130Z/
Carbon PA-Monroe PA-
918 PM EDT Mon Sep 13 2021

...THE SEVERE THUNDERSTORM WARNING FOR 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.

A Severe Thunderstorm Watch remains in effect until 100 AM EDT for
northwestern New Jersey...and eastern and southeastern Pennsylvania.

LAT...LON 4087 7485 4067 7501 4059 7519 4061 7520
      4044 7552 4063 7582 4091 7504
TIME...MOT...LOC 0118Z 297DEG 37KT 4074 7489 4068 7502 4061 7535 4051
7560

$$

NJC019-041-PAC077-095-140130-
/O.CON.KPHI.SV.W.0300.000000T0000Z-210914T0130Z/
Hunterdon NJ-Warren NJ-Lehigh PA-Northampton PA-
918 PM EDT Mon Sep 13 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 PM EDT
FOR NORTHWESTERN HUNTERDON...CENTRAL WARREN...LEHIGH AND NORTHAMPTON
COUNTIES...

At 918 PM EDT, severe thunderstorms were located along a line
extending from near Califon to near Hampton to Bethlehem to Ancient
Oaks, moving southeast at 40 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Allentown, Easton, Bethlehem, Forks, Emmaus, Northampton, Wilson,
Washington, Hellertown, Nazareth, Bath, Belvidere, Harmony, Oxford,
Alpha, Belfast, Hampton, West Easton, Tatamy and Bloomsbury.

This includes the following highways...
 Northeast Extension between mile markers 47 and 65.
 Interstate 78 in Pennsylvania between mile markers 45 and 76.
 Interstate 78 in New Jersey between mile markers 0 and 9.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Frequent cloud to ground lightning is occurring with these storms.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

&&

LAT...LON 4087 7485 4067 7501 4059 7519 4061 7520
      4044 7552 4063 7582 4091 7504
TIME...MOT...LOC 0118Z 297DEG 37KT 4074 7489 4068 7502 4061 7535 4051
7560

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Gorse

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 13, 9:03 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Morris, Somerset, Sussex, Warren	109 min
Sep 13, 9:03 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Somerset, Warren	57 min
Sep 13, 9:12 PM EDT	Flash Flood Warning	PHI	Hunterdon, Morris, Warren	114 min
Sep 13, 9:21 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Somerset, Warren	38 min
Sep 13, 9:34 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Morris, Somerset	38 min
Sep 13, 9:53 PM EDT	Severe Thunderstorm Warning	PHI	Mercer, Middlesex, Monmouth, Somerset	52 min
Sep 13, 10:03 PM EDT	Special Marine Warning	PHI		57 min
Sep 13, 8:16 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	44 min
Sep 13, 8:51 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	108 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2021 Severe Thunderstorm Warnings in New Jersey, 2021 Every severe thunderstorm warning in 2021

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.